Biology guide - IB Documents SUBJECT GUIDES/Group 4... · 2019-06-11 · Biology guide 5...

Biology guideFirst assessment 2016

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Diploma ProgrammeBiology guide

IB mission statementThe International Baccalaureate aims to develop inquiring, knowledgeable and caring young people who help to create a better and more peaceful world through intercultural understanding and respect.

To this end the organization works with schools, governments and international organizations to develop challenging programmes of international education and rigorous assessment.

These programmes encourage students across the world to become active, compassionate and lifelong learners who understand that other people, with their differences, can also be right.

Biology guide

Contents

Introduction 1

Purpose of this document 1

The Diploma Programme 2

Nature of science 6

Nature of biology 13

Aims 18

Assessment objectives 19

Syllabus 20

Syllabus outline 20

Approaches to the teaching and learning of biology 21

Syllabus content 25

Assessment 142

Assessment in the Diploma Programme 142

Assessment outline—SL 144

Assessment outline—HL 145

External assessment 146

Internal assessment 148

The group 4 project 161

Appendices 166

Glossary of command terms 166

Bibliography 168

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Introduction

Purpose of this document

This publication is intended to guide the planning, teaching and assessment of the subject in schools. Subject teachers are the primary audience, although it is expected that teachers will use the guide to inform students and parents about the subject.

This guide can be found on the subject page of the online curriculum centre (OCC) at http://occ.ibo.org, a password-protected IB website designed to support IB teachers. It can also be purchased from the IB store at http://store.ibo.org.

Additional resourcesAdditional publications such as teacher support materials, subject reports, internal assessment guidance and grade descriptors can also be found on the OCC. Past examination papers as well as markschemes can be purchased from the IB store.

Teachers are encouraged to check the OCC for additional resources created or used by other teachers. Teachers can provide details of useful resources, for example: websites, books, videos, journals or teaching ideas.

AcknowledgmentThe IB wishes to thank the educators and associated schools for generously contributing time and resources to the production of this guide.

First assessment 2016

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Introduction

The Diploma Programme

The Diploma Programme is a rigorous pre-university course of study designed for students in the 16 to 19 age range. It is a broad-based two-year course that aims to encourage students to be knowledgeable and inquiring, but also caring and compassionate. There is a strong emphasis on encouraging students to develop intercultural understanding, open-mindedness, and the attitudes necessary for them to respect and evaluate a range of points of view.

The Diploma Programme modelThe course is presented as six academic areas enclosing a central core (see figure 1). It encourages the concurrent study of a broad range of academic areas. Students study: two modern languages (or a modern language and a classical language); a humanities or social science subject; a science; mathematics and one of the creative arts. It is this comprehensive range of subjects that makes the Diploma Programme a demanding course of study designed to prepare students effectively for university entrance. In each of the academic areas students have flexibility in making their choices, which means they can choose subjects that particularly interest them and that they may wish to study further at university.

Figure 1Diploma Programme model


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Choosing the right combinationStudents are required to choose one subject from each of the six academic areas, although they can, instead of an arts subject, choose two subjects from another area. Normally, three subjects (and not more than four) are taken at higher level (HL), and the others are taken at standard level (SL). The IB recommends 240 teaching hours for HL subjects and 150 hours for SL. Subjects at HL are studied in greater depth and breadth than at SL.

At both levels, many skills are developed, especially those of critical thinking and analysis. At the end of the course, students’ abilities are measured by means of external assessment. Many subjects contain some element of coursework assessed by teachers.

The core of the Diploma Programme modelAll Diploma Programme students participate in the three course elements that make up the core of the model.

Theory of knowledge (TOK) is a course that is fundamentally about critical thinking and inquiry into the process of knowing rather than about learning a specific body of knowledge. The TOK course examines the nature of knowledge and how we know what we claim to know. It does this by encouraging students to analyse knowledge claims and explore questions about the construction of knowledge. The task of TOK is to emphasize connections between areas of shared knowledge and link them to personal knowledge in such a way that an individual becomes more aware of his or her own perspectives and how they might differ from others.

Creativity, action, service (CAS) is at the heart of the Diploma Programme. The emphasis in CAS is on helping students to develop their own identities, in accordance with the ethical principles embodied in the IB mission statement and the IB learner profile. It involves students in a range of activities alongside their academic studies throughout the Diploma Programme. The three strands of CAS are Creativity (arts, and other experiences that involve creative thinking), Action (physical exertion contributing to a healthy lifestyle) and Service (an unpaid and voluntary exchange that has a learning benefit for the student). Possibly, more than any other component in the Diploma Programme, CAS contributes to the IB’s mission to create a better and more peaceful world through intercultural understanding and respect.

The extended essay, including the world studies extended essay, offers the opportunity for IB students to investigate a topic of special interest, in the form of a 4,000-word piece of independent research. The area of research undertaken is chosen from one of the students’ Diploma Programme subjects, or in the case of the interdisciplinary world studies essay, two subjects, and acquaints them with the independent research and writing skills expected at university. This leads to a major piece of formally presented, structured writing, in which ideas and findings are communicated in a reasoned and coherent manner, appropriate to the subject or subjects chosen. It is intended to promote high-level research and writing skills, intellectual discovery and creativity. As an authentic learning experience it provides students with an opportunity to engage in personal research on a topic of choice, under the guidance of a supervisor.


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Approaches to teaching and approaches to learningApproaches to teaching and learning across the Diploma Programme refers to deliberate strategies, skills and attitudes which permeate the teaching and learning environment. These approaches and tools, intrinsically linked with the learner profile attributes, enhance student learning and assist student preparation for the Diploma Programme assessment and beyond. The aims of approaches to teaching and learning in the Diploma Programme are to:

• empower teachers as teachers of learners as well as teachers of content

• empower teachers to create clearer strategies for facilitating learning experiences in which students are more meaningfully engaged in structured inquiry and greater critical and creative thinking

• promote both the aims of individual subjects (making them more than course aspirations) and linking previously isolated knowledge (concurrency of learning)

• encourage students to develop an explicit variety of skills that will equip them to continue to be actively engaged in learning after they leave school, and to help them not only obtain university admission through better grades but also prepare for success during tertiary education and beyond

• enhance further the coherence and relevance of the students’ Diploma Programme experience

• allow schools to identify the distinctive nature of an IB Diploma Programme education, with its blend of idealism and practicality.

The five approaches to learning (developing thinking skills, social skills, communication skills, self-management skills and research skills) along with the six approaches to teaching (teaching that is inquiry-based, conceptually focused, contextualized, collaborative, differentiated and informed by assessment) encompass the key values and principles that underpin IB pedagogy.

The IB mission statement and the IB learner profileThe Diploma Programme aims to develop in students the knowledge, skills and attitudes they will need to fulfill the aims of the IB, as expressed in the organization’s mission statement and the learner profile. Teaching and learning in the Diploma Programme represent the reality in daily practice of the organization’s educational philosophy.

Academic honestyAcademic honesty in the Diploma Programme is a set of values and behaviours informed by the attributes of the learner profile. In teaching, learning and assessment, academic honesty serves to promote personal integrity, engender respect for the integrity of others and their work, and ensure that all students have an equal opportunity to demonstrate the knowledge and skills they acquire during their studies.

All coursework—including work submitted for assessment—is to be authentic, based on the student’s individual and original ideas with the ideas and work of others fully acknowledged. Assessment tasks that require teachers to provide guidance to students or that require students to work collaboratively must be completed in full compliance with the detailed guidelines provided by the IB for the relevant subjects.

For further information on academic honesty in the IB and the Diploma Programme, please consult the IB publications Academic honesty, The Diploma Programme: From principles into practice and General regulations: Diploma Programme. Specific information regarding academic honesty as it pertains to external and internal assessment components of this Diploma Programme subject can be found in this guide.


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Acknowledging the ideas or work of another personCoordinators and teachers are reminded that candidates must acknowledge all sources used in work submitted for assessment. The following is intended as a clarification of this requirement.

Diploma Programme candidates submit work for assessment in a variety of media that may include audio-visual material, text, graphs, images and/or data published in print or electronic sources. If a candidate uses the work or ideas of another person, the candidate must acknowledge the source using a standard style of referencing in a consistent manner. A candidate’s failure to acknowledge a source will be investigated by the IB as a potential breach of regulations that may result in a penalty imposed by the IB final award committee.

The IB does not prescribe which style(s) of referencing or in-text citation should be used by candidates; this is left to the discretion of appropriate faculty/staff in the candidate’s school. The wide range of subjects, three response languages and the diversity of referencing styles make it impractical and restrictive to insist on particular styles. In practice, certain styles may prove most commonly used, but schools are free to choose a style that is appropriate for the subject concerned and the language in which candidates’ work is written. Regardless of the reference style adopted by the school for a given subject, it is expected that the minimum information given includes: name of author, date of publication, title of source, and page numbers as applicable.

Candidates are expected to use a standard style and use it consistently so that credit is given to all sources used, including sources that have been paraphrased or summarized. When writing text candidates must clearly distinguish between their words and those of others by the use of quotation marks (or other method, such as indentation) followed by an appropriate citation that denotes an entry in the bibliography. If an electronic source is cited, the date of access must be indicated. Candidates are not expected to show faultless expertise in referencing, but are expected to demonstrate that all sources have been acknowledged. Candidates must be advised that audio-visual material, text, graphs, images and/or data published in print or in electronic sources that is not their own must also attribute the source. Again, an appropriate style of referencing/citation must be used.

Learning diversity and learning support requirementsSchools must ensure that equal access arrangements and reasonable adjustments are provided to candidates with learning support requirements that are in line with the IB documents Candidates with assessment access requirements and Learning diversity within the International Baccalaureate programmes/Special educational needs within the International Baccalaureate programmes.

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Introduction

Nature of science

The Nature of science (NOS) is an overarching theme in the biology, chemistry and physics courses. This section, titled Nature of science, is in the biology, chemistry and physics guides to support teachers in their understanding of what is meant by the nature of science. The “Nature of science” section of the guide provides a comprehensive account of the nature of science in the 21st century. It will not be possible to cover in this document all the themes in detail in the three science courses, either for teaching or assessment.

It has a paragraph structure (1.1, 1.2, etc.) to link the significant points made to the syllabus (landscape pages) references on the NOS. The NOS parts in the subject-specific sections of the guide are examples of a particular understanding. The NOS statement(s) above every sub-topic outline how one or more of the NOS themes can be exemplified through the understandings, applications and skills in that sub-topic. These are not a repeat of the NOS statements found below but an elaboration of them in a specific context. See the section on “Format of the syllabus”.

Technology

Although this section is about the nature of science, the interpretation of the word technology is important, and the role of technology emerging from and contributing to science needs to be clarified. In today’s world, the words science and technology are often used interchangeably, however historically this is not the case. Technology emerged before science, and materials were used to produce useful and decorative artefacts long before there was an understanding of why materials had different properties that could be used for different purposes. In the modern world the reverse is the case: an understanding of the underlying science is the basis for technological developments. These new technologies in their turn drive developments in science.

Despite their mutual dependence they are based on different values: science on evidence, rationality and the quest for deeper understanding; technology on the practical, the appropriate and the useful with an increasingly important emphasis on sustainability.

1. What is science and what is the scientific endeavour? 1.1. The underlying assumption of science is that the universe has an independent, external reality

accessible to human senses and amenable to human reason.

1.2. Pure science aims to come to a common understanding of this external universe; applied science and engineering develop technologies that result in new processes and products. However, the boundaries between these fields are fuzzy.

1.3. Scientists use a wide variety of methodologies which taken together, make up the process of science. There is no single “scientific method”. Scientists have used, and do use, different methods at different times to build up their knowledge and ideas but they have a common understanding about what makes them all scientifically valid.

1.4. This is an exciting and challenging adventure involving much creativity and imagination as well as exacting and detailed thinking and application. Scientists also have to be ready for unplanned, surprising, accidental discoveries. The history of science shows this is a very common occurrence.

Nature of science

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1.5. Many scientific discoveries have involved flashes of intuition and many have come from speculation or simple curiosity about particular phenomena.

1.6. Scientists have a common terminology and a common reasoning process, which involves using deductive and inductive logic through analogies and generalizations. They share mathematics, the language of science, as a powerful tool. Indeed, some scientific explanations only exist in mathematical form.

1.7. Scientists must adopt a skeptical attitude to claims. This does not mean that they disbelieve everything, but rather that they suspend judgment until they have a good reason to believe a claim to be true or false. Such reasons are based on evidence and argument.

1.8. The importance of evidence is a fundamental common understanding. Evidence can be obtained by observation or experiment. It can be gathered by human senses, primarily sight, but much modern science is carried out using instrumentation and sensors that can gather information remotely and automatically in areas that are too small, or too far away, or otherwise beyond human sense perception. Improved instrumentation and new technology have often been the drivers for new discoveries. Observations followed by analysis and deduction led to the Big Bang theory of the origin of the universe and to the theory of evolution by natural selection. In these cases, no controlled experiments were possible. Disciplines such as geology and astronomy rely strongly on collecting data in the field, but all disciplines use observation to collect evidence to some extent. Experimentation in a controlled environment, generally in laboratories, is the other way of obtaining evidence in the form of data, and there are many conventions and understandings as to how this is to be achieved.

1.9. This evidence is used to develop theories, generalize from data to form laws and propose hypotheses. These theories and hypotheses are used to make predictions that can be tested. In this way theories can be supported or opposed and can be modified or replaced by new theories.

1.10. Models, some simple, some very complex, based on theoretical understanding, are developed to explain processes that may not be observable. Computer-based mathematical models are used to make testable predictions, which can be especially useful when experimentation is not possible. Models tested against experiments or data from observations may prove inadequate, in which case they may be modified or replaced by new models.

1.11. The outcomes of experiments, the insights provided by modelling and observations of the natural world may be used as further evidence for a claim.

1.12. The growth in computing power has made modelling much more powerful. Models, usually mathematical, are now used to derive new understandings when no experiments are possible (and sometimes when they are). This dynamic modelling of complex situations involving large amounts of data, a large number of variables and complex and lengthy calculations is only possible as a result of increased computing power. Modelling of the Earth’s climate, for example, is used to predict or make a range of projections of future climatic conditions. A range of different models have been developed in this field and results from different models have been compared to see which models are most accurate. Models can sometimes be tested by using data from the past and used to see if they can predict the present situation. If a model passes this test, we gain confidence in its accuracy.

1.13. Both the ideas and the processes of science can only occur in a human context. Science is carried out by a community of people from a wide variety of backgrounds and traditions, and this has clearly influenced the way science has proceeded at different times. It is important to understand, however, that to do science is to be involved in a community of inquiry with certain common principles, methodologies, understandings and processes.

Nature of science

Biology guide8

2. The understanding of science2.1. Theories, laws and hypotheses are concepts used by scientists. Though these concepts are connected,

there is no progression from one to the other. These words have a special meaning in science and it is important to distinguish these from their everyday use.

2.2. Theories are themselves integrated, comprehensive models of how the universe, or parts of it, work. A theory can incorporate facts and laws and tested hypotheses. Predictions can be made from the theories and these can be tested in experiments or by careful observations. Examples are the germ theory of disease or atomic theory.

2.3. Theories generally accommodate the assumptions and premises of other theories, creating a consistent understanding across a range of phenomena and disciplines. Occasionally, however, a new theory will radically change how essential concepts are understood or framed, impacting other theories and causing what is sometimes called a “paradigm shift” in science. One of the most famous paradigm shifts in science occurred when our idea of time changed from an absolute frame of reference to an observer-dependent frame of reference within Einstein’s theory of relativity. Darwin’s theory of evolution by natural selection also changed our understanding of life on Earth.

2.4. Laws are descriptive, normative statements derived from observations of regular patterns of behaviour. They are generally mathematical in form and can be used to calculate outcomes and to make predictions. Like theories and hypotheses, laws cannot be proven. Scientific laws may have exceptions and may be modified or rejected based on new evidence. Laws do not necessarily explain a phenomenon. For example, Newton’s law of universal gravitation tells us that the force between two masses is inversely proportional to the square of the distance between them, and allows us to calculate the force between masses at any distance apart, but it does not explain why masses attract each other. Also, note that the term law has been used in different ways in science, and whether a particular idea is called a law may be partly a result of the discipline and time period at which it was developed.

2.5. Scientists sometimes form hypotheses—explanatory statements about the world that could be true or false, and which often suggest a causal relationship or a correlation between factors. Hypotheses can be tested by both experiments and observations of the natural world and can be supported or opposed.

2.6. To be scientific, an idea (for example, a theory or hypothesis) must focus on the natural world and natural explanations and must be testable. Scientists strive to develop hypotheses and theories that are compatible with accepted principles and that simplify and unify existing ideas.

2.7. The principle of Occam’s razor is used as a guide to developing a theory. The theory should be as simple as possible while maximizing explanatory power.

2.8. The ideas of correlation and cause are very important in science. A correlation is a statistical link or association between one variable and another. A correlation can be positive or negative and a correlation coefficient can be calculated that will have a value between +1, 0 and -1. A strong correlation (positive or negative) between one factor and another suggests some sort of causal relationship between the two factors but more evidence is usually required before scientists accept the idea of a causal relationship. To establish a causal relationship, ie one factor causing another, scientists need to have a plausible scientific mechanism linking the factors. This strengthens the case that one causes the other, for example smoking and lung cancer. This mechanism can be tested in experiments.

2.9. The ideal situation is to investigate the relationship between one factor and another while controlling all other factors in an experimental setting; however this is often impossible and scientists, especially in biology and medicine, use sampling, cohort studies and case control studies to strengthen their understanding of causation when experiments (such as double blind tests and clinical trials) are not possible. Epidemiology in the field of medicine involves the statistical analysis of data to discover possible correlations when little established scientific knowledge is available or the circumstances are too difficult to control entirely. Here, as in other fields, mathematical analysis of probability also plays a role.

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3. The objectivity of science3.1. Data is the lifeblood of scientists and may be qualitative or quantitative. It can be obtained purely from

observations or from specifically designed experiments, remotely using electronic sensors or by direct measurement. The best data for making accurate and precise descriptions and predictions is often quantitative and amenable to mathematical analysis. Scientists analyse data and look for patterns, trends and discrepancies, attempting to discover relationships and establish causal links. This is not always possible, so identifying and classifying observations and artefacts (eg types of galaxies or fossils) is still an important aspect of scientific work.

3.2. Taking repeated measurements and large numbers of readings can improve reliability in data collection. Data can be presented in a variety of formats such as linear and logarithmic graphs that can be analysed for, say, direct or inverse proportion or for power relationships.

3.3. Scientists need to be aware of random errors and systematic errors, and use techniques such as error bars and lines of best fit on graphs to portray the data as realistically and honestly as possible. There is a need to consider whether outlying data points should be discarded or not.

3.4. Scientists need to understand the difference between errors and uncertainties, accuracy and precision, and need to understand and use the mathematical ideas of average, mean, mode, median, etc. Statistical methods such as standard deviation and chi-squared tests are often used. It is important to be able to assess how accurate a result is. A key part of the training and skill of scientists is in being able to decide which technique is appropriate in different circumstances.

3.5. It is also very important for scientists to be aware of the cognitive biases that may impact experimental design and interpretation. The confirmation bias, for example, is a well-documented cognitive bias that urges us to find reasons to reject data that is unexpected or does not conform to our expectations or desires, and to perhaps too readily accept data that agrees with these expectations or desires. The processes and methodologies of science are largely designed to account for these biases. However care must always be taken to avoid succumbing to them.

3.6. Although scientists cannot ever be certain that a result or finding is correct, we know that some scientific results are very close to certainty. Scientists often speak of “levels of confidence” when discussing outcomes. The discovery of the existence of a Higgs boson is such an example of a “level of confidence”. This particle may never be directly observable, but to establish its “existence” particle physicists had to pass the self-imposed definition of what can be regarded as a discovery—the 5-sigma “level of certainty”—or about a 0.00003% chance that the effect is not real based on experimental evidence.

3.7. In recent decades, the growth in computing power, sensor technology and networks has allowed scientists to collect large amounts of data. Streams of data are downloaded continuously from many sources such as remote sensing satellites and space probes and large amounts of data are generated in gene sequencing machines. Experiments in CERN’s Large Hadron Collider regularly produce 23 petabytes of data per second, which is equivalent to 13.3 years of high definition TV content per second.

3.8. Research involves analysing large amounts of this data, stored in databases, looking for patterns and unique events. This has to be done using software which is generally written by the scientists involved. The data and the software may not be published with the scientific results but would be made generally available to other researchers.

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4. The human face of science4.1. Science is highly collaborative and the scientific community is composed of people working in science,

engineering and technology. It is common to work in teams from many disciplines so that different areas of expertise and specializations can contribute to a common goal that is beyond one scientific field. It is also the case that how a problem is framed in the paradigm of one discipline might limit possible solutions, so framing problems using a variety of perspectives, in which new solutions are possible, can be extremely useful.

4.2. Teamwork of this sort takes place with the common understanding that science should be open-minded and independent of religion, culture, politics, nationality, age and gender. Science involves the free global interchange of information and ideas. Of course, individual scientists are human and may have biases and prejudices, but the institutions, practices and methodologies of science help keep the scientific endeavour as a whole unbiased.

4.3. As well as collaborating on the exchange of results, scientists work on a daily basis in collaborative groups on a small and large scale within and between disciplines, laboratories, organizations and countries, facilitated even more by virtual communication. Examples of large-scale collaboration include:

– The Manhattan project, the aim of which was to build and test an atomic bomb. It eventually employed more than 130,000 people and resulted in the creation of multiple production and research sites that operated in secret, culminating in the dropping of two atomic bombs on Hiroshima and Nagasaki.

– The Human Genome Project (HGP), which was an international scientific research project set up to map the human genome. The $3-billion project beginning in 1990 produced a draft of the genome in 2000. The sequence of the DNA is stored in databases available to anyone on the internet.

– The IPCC (Intergovernmental Panel on Climate Change), organized under the auspices of The United Nations, is officially composed of about 2,500 scientists. They produce reports summarizing the work of many more scientists from all around the world.

– CERN, the European Organization for Nuclear Research, an international organization set up in 1954, is the world’s largest particle physics laboratory. The laboratory, situated in Geneva, employs about 2,400 people and shares results with 10,000 scientists and engineers covering over 100 nationalities from 600 or more universities and research facilities.

All the above examples are controversial to some degree and have aroused emotions among scientists and the public.

4.4. Scientists spend a considerable amount of time reading the published results of other scientists. They publish their own results in scientific journals after a process called peer review. This is when the work of a scientist or, more usually, a team of scientists is anonymously and independently reviewed by several scientists working in the same field who decide if the research methodologies are sound and if the work represents a new contribution to knowledge in that field. They also attend conferences to make presentations and display posters of their work. Publication of peer-reviewed journals on the internet has increased the efficiency with which the scientific literature can be searched and accessed. There are a large number of national and international organizations for scientists working in specialized areas within subjects.

4.5. Scientists often work in areas, or produce findings, that have significant ethical and political implications. These areas include cloning, genetic engineering of food and organisms, stem cell and reproductive technologies, nuclear power, weapons development (nuclear, chemical and biological), transplantation of tissue and organs and in areas that involve testing on animals (see IB animal experimentation policy). There are also questions involving intellectual property rights and

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the free exchange of information that may impact significantly on a society. Science is undertaken in universities, commercial companies, government organizations, defence agencies and international organizations. Questions of patents and intellectual property rights arise when work is done in a protected environment.

4.6. The integrity and honest representation of data is paramount in science—results should not be fixed or manipulated or doctored. To help ensure academic honesty and guard against plagiarism, all sources are quoted and appropriate acknowledgment made of help or support. Peer review and the scrutiny and skepticism of the scientific community also help achieve these goals.

4.7. All science has to be funded and the source of the funding is crucial in decisions regarding the type of research to be conducted. Funding from governments and charitable foundations is sometimes for pure research with no obvious direct benefit to anyone whereas funding from private companies is often for applied research to produce a particular product or technology. Political and economic factors often determine the nature and extent of the funding. Scientists often have to spend time applying for research grants and have to make a case for what they want to research.

4.8. Science has been used to solve many problems and improve man’s lot, but it has also been used in morally questionable ways and in ways that inadvertently caused problems. Advances in sanitation, clean water supplies and hygiene led to significant decreases in death rates but without compensating decreases in birth rates this led to huge population increases with all the problems of resources, energy and food supplies that entails. Ethical discussions, risk-benefit analyses, risk assessment and the precautionary principle are all parts of the scientific way of addressing the common good.

5. Scientific literacy and the public understanding of science 5.1. An understanding of the nature of science is vital when society needs to make decisions involving

scientific findings and issues. How does the public judge? It may not be possible to make judgments based on the public’s direct understanding of a science, but important questions can be asked about whether scientific processes were followed and scientists have a role in answering such questions.

5.2. As experts in their particular fields, scientists are well placed to explain to the public their issues and findings. Outside their specializations, they may be no more qualified than ordinary citizens to advise others on scientific issues, although their understanding of the processes of science can help them to make personal decisions and to educate the public as to whether claims are scientifically credible.

5.3. As well as comprising knowledge of how scientists work and think, scientific literacy involves being aware of faulty reasoning. There are many cognitive biases/fallacies of reasoning to which people are susceptible (including scientists) and these need to be corrected whenever possible. Examples of these are the confirmation bias, hasty generalizations, post hoc ergo propter hoc (false cause), the straw man fallacy, redefinition (moving the goal posts), the appeal to tradition, false authority and the accumulation of anecdotes being regarded as evidence.

5.4. When such biases and fallacies are not properly managed or corrected, or when the processes and checks and balances of science are ignored or misapplied, the result is pseudoscience. Pseudoscience is the term applied to those beliefs and practices which claim to be scientific but do not meet or follow the standards of proper scientific methodologies, ie they lack supporting evidence or a theoretical framework, are not always testable and hence falsifiable, are expressed in a non-rigorous or unclear manner and often fail to be supported by scientific testing.

5.5. Another key issue is the use of appropriate terminology. Words that scientists agree on as being scientific terms will often have a different meaning in everyday life and scientific discourse with the public needs to take this into account. For example, a theory in everyday use means a hunch or

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speculation, but in science an accepted theory is a scientific idea that has produced predictions that have been thoroughly tested in many different ways. An aerosol is just a spray can to the general public, but in science it is a suspension of solid or liquid particles in a gas.

5.6. Whatever the field of science—whether it is in pure research, applied research or in engineering new technology—there is boundless scope for creative and imaginative thinking. Science has achieved a great deal but there are many, many unanswered questions to challenge future scientists.

The flow chart below is part of an interactive flow chart showing the scientific process of inquiry in practice. The interactive version can be found at “How science works: The flowchart”. Understanding Science. University of California Museum of Paleontology. 1 February 2013 <http://undsci.berkeley.edu/article/scienceflowchart>.

Figure 2Pathways to scientific discovery

Supportive, contradictory, surprisingor inconclusive data may...

Developtechnology

Addresssocietal issues

Satisfycuriosity

Solve everydayproblems

Buildknowledge

Informpolicy

Makingobservations

Askingquestions

Findinginspiration

Exploring theliterature

Sharing dataand ideas

...oppose ahypothesis.

Discussion withcolleagues

Feedback andpeer review

Coming upwith new

questions/ideas

Publication

Replication

Theorybuilding

EXPLORATIONAND DISCOVERY

COMMUNITYANALYSIS AND

FEEDBACK

BENEFITS ANDOUTCOMES

TESTINGIDEAS

Gathering data

Interpreting data

New technology

Curiosity

Practical problem

Personal motivation

Surprising observation

Serendipity

Hypotheses Expectedresults/observations

Actualresults/observations

...support ahypothesis.

... inspirerevised/newhypothesis.

... inspirerevised

assumptions.

How science works

www.understandingscience.org© 2008 The University of California Museum of Paleontology, Berkeley, and the Regents of the University of California

Biology guide 1313

Introduction

Nature of biology

Biology is the study of life. The first organisms appeared on the planet over 3 billion years ago and, through reproduction and natural selection, have given rise to the 8 million or so different species alive today. Estimates vary, but over the course of evolution 4 billion species could have been produced. Most of these flourished for a period of time and then became extinct as new, better adapted species took their place. There have been at least five periods when very large numbers of species became extinct and biologists are concerned that another mass extinction is under way, caused this time by human activity. Nonetheless, there are more species alive on Earth today than ever before. This diversity makes biology both an endless source of fascination and a considerable challenge.

An interest in life is natural for humans; not only are we living organisms ourselves, but we depend on many species for our survival, are threatened by some and co-exist with many more. From the earliest cave paintings to the modern wildlife documentary, this interest is as obvious as it is ubiquitous, as biology continues to fascinate young and old all over the world.

The word “biology” was coined by German naturalist Gottfried Reinhold in 1802 but our understanding of living organisms only started to grow rapidly with the advent of techniques and technologies developed in the 18th and 19th centuries, not least the invention of the microscope and the realization that natural selection is the process that has driven the evolution of life.

Biologists attempt to understand the living world at all levels using many different approaches and techniques. At one end of the scale is the cell, its molecular construction and complex metabolic reactions. At the other end of the scale biologists investigate the interactions that make whole ecosystems function.

Many areas of research in biology are extremely challenging and many discoveries remain to be made. Biology is still a young science and great progress is expected in the 21st century. This progress is sorely needed at a time when the growing human population is placing ever greater pressure on food supplies and on the habitats of other species, and is threatening the very planet we occupy.

Teaching approachThere are a variety of approaches to the teaching of biology. By its very nature, biology lends itself to an experimental approach, and it is expected that this will be reflected throughout the course.

The order in which the syllabus is arranged is not the order in which it should be taught, and it is up to individual teachers to decide on an arrangement that suits their circumstances. Sections of the option material may be taught within the core or the additional higher level (AHL) material if desired or the option material can be taught as a separate unit.

Nature of biology

Biology guide14

Science and the international dimensionScience itself is an international endeavour—the exchange of information and ideas across national boundaries has been essential to the progress of science. This exchange is not a new phenomenon but it has accelerated in recent times with the development of information and communication technologies. Indeed, the idea that science is a Western invention is a myth—many of the foundations of modern-day science were laid many centuries before by Arabic, Indian and Chinese civilizations, among others. Teachers are encouraged to emphasize this contribution in their teaching of various topics, perhaps through the use of timeline websites. The scientific method in its widest sense, with its emphasis on peer review, open-mindedness and freedom of thought, transcends politics, religion, gender and nationality. Where appropriate within certain topics, the syllabus details sections in the group 4 guides contain links illustrating the international aspects of science.

On an organizational level, many international bodies now exist to promote science. United Nations bodies such as UNESCO, UNEP and WMO, where science plays a prominent part, are well known, but in addition there are hundreds of international bodies representing every branch of science. The facilities for large-scale research in, for example, particle physics and the Human Genome Project are expensive, and only joint ventures involving funding from many countries allow this to take place. The data from such research is shared by scientists worldwide. Group 4 teachers and students are encouraged to access the extensive websites and databases of these international scientific organizations to enhance their appreciation of the international dimension.

Increasingly there is a recognition that many scientific problems are international in nature and this has led to a global approach to research in many areas. The reports of the Intergovernmental Panel on Climate Change are a prime example of this. On a practical level, the group 4 project (which all science students must undertake) mirrors the work of real scientists by encouraging collaboration between schools across the regions.

The power of scientific knowledge to transform societies is unparalleled. It has the potential to produce great universal benefits, or to reinforce inequalities and cause harm to people and the environment. In line with the IB mission statement, group 4 students need to be aware of the moral responsibility of scientists to ensure that scientific knowledge and data are available to all countries on an equitable basis and that they have the scientific capacity to use this for developing sustainable societies.

Students’ attention should be drawn to sections of the syllabus with links to international-mindedness. Examples of issues relating to international-mindedness are given within sub-topics in the syllabus content. Teachers could also use resources found on the Global Engage website (http://globalengage. ibo.org).

Distinction between SL and HLGroup 4 students at standard level (SL) and higher level (HL) undertake a common core syllabus, a common internal assessment (IA) scheme and have some overlapping elements in the option studied. They are presented with a syllabus that encourages the development of certain skills, attributes and attitudes, as described in the “Assessment objectives” section of the guide.

While the skills and activities of group 4 science subjects are common to students at both SL and HL, students at HL are required to study some topics in greater depth, in the additional higher level (AHL) material and in the common options. The distinction between SL and HL is one of breadth and depth.

Nature of biology

Biology guide 15

Prior learningPast experience shows that students will be able to study a group 4 science subject at SL successfully with no background in, or previous knowledge of, science. Their approach to learning, characterized by the IB learner profile attributes, will be significant here.

However, for most students considering the study of a group 4 subject at HL, while there is no intention to restrict access to group 4 subjects, some previous exposure to formal science education would be necessary. Specific topic details are not specified but students who have undertaken the IB Middle Years Programme (MYP) or studied an equivalent national science qualification or a school-based science course would be well prepared for an HL subject.

Links to the Middle Years ProgrammeStudents who have undertaken the MYP science, design and mathematics courses will be well prepared for group 4 subjects. The alignment between MYP science and the Diploma Programme group 4 courses allows for a smooth transition for students between programmes. The concurrent planning of the new group 4 courses and MYP: Next Chapter (both launched in 2014) has helped develop a closer alignment.

Scientific inquiry is central to teaching and learning science in the MYP. It enables students to develop a way of thinking and a set of skills and processes that, while allowing them to acquire and use knowledge, equip them with the capabilities to tackle, with confidence, the internal assessment component of group 4 subjects. The vision of MYP sciences is to contribute to the development of students as 21st century learners. A holistic sciences programme allows students to develop and utilize a mixture of cognitive abilities, social skills, personal motivation, conceptual knowledge and problem-solving competencies within an inquiry-based learning environment (Rhoton 2010). Inquiry aims to support students’ understanding by providing them with opportunities to independently and collaboratively investigate relevant issues through both research and experimentation. This forms a firm base of scientific understanding with deep conceptual roots for students entering group 4 courses.

In the MYP, teachers make decisions about student achievement using their professional judgment, guided by criteria that are public, precise and known in advance, ensuring that assessment is transparent. The IB describes this approach as “criterion-related”—a philosophy of assessment that is neither “norm-referenced” (where students must be compared to each other and to an expected distribution of achievement) nor “criterion-referenced” (where students must master all strands of specific criteria at lower achievement levels before they can be considered to have achieved the next level). It is important to emphasize that the single most important aim of MYP assessment (consistent with the PYP and DP) is to support curricular goals and encourage appropriate student learning. Assessments are based upon evaluating course aims and objectives and, therefore, effective teaching to the course requirements also ensures effective teaching for formal assessment requirements. Students need to understand what the assessment expectations, standards and practices are and these should all be introduced early and naturally in teaching, as well as in class and homework activities. Experience with criterion-related assessment greatly assists students entering group 4 courses with understanding internal assessment requirements.

MYP science is a concept-driven curriculum, aimed at helping the learner construct meaning through improved critical thinking and the transfer of knowledge. At the top level are key concepts which are broad, organizing, powerful ideas that have relevance within the science course but also transcend it, having relevance in other subject groups. These key concepts facilitate both disciplinary and interdisciplinary learning as well as making connections with other subjects. While the key concepts provide breadth, the related concepts in MYP science add depth to the programme. The related concept can be considered to be the big idea of the unit which brings focus and depth and leads students towards the conceptual understanding.

Nature of biology

Biology guide16

Across the MYP there are 16 key concepts with the three highlighted below the focus for MYP science.

The key concepts across the MYP curriculum

Aesthetics Change Communication Communities

Connections Creativity Culture Development

Form Global interactions Identity Logic

Perspective Relationships SystemsTime, place and space

MYP students may in addition undertake an optional onscreen concept-based assessment as further preparation for Diploma Programme science courses.

Science and theory of knowledgeThe theory of knowledge (TOK) course (first assessment 2015) engages students in reflection on the nature of knowledge and on how we know what we claim to know. The course identifies eight ways of knowing: reason, emotion, language, sense perception, intuition, imagination, faith and memory. Students explore these means of producing knowledge within the context of various areas of knowledge: the natural sciences, the social sciences, the arts, ethics, history, mathematics, religious knowledge systems and indigenous knowledge systems. The course also requires students to make comparisons between the different areas of knowledge, reflecting on how knowledge is arrived at in the various disciplines, what the disciplines have in common, and the differences between them.

TOK lessons can support students in their study of science, just as the study of science can support students in their TOK course. TOK provides a space for students to engage in stimulating wider discussions about questions such as what it means for a discipline to be a science, or whether there should be ethical constraints on the pursuit of scientific knowledge. It also provides an opportunity for students to reflect on the methodologies of science, and how these compare to the methodologies of other areas of knowledge. It is now widely accepted that there is no one scientific method, in the strict Popperian sense. Instead, the sciences utilize a variety of approaches in order to produce explanations for the behaviour of the natural world. The different scientific disciplines share a common focus on utilizing inductive and deductive reasoning, on the importance of evidence, and so on. Students are encouraged to compare and contrast these methods with the methods found in, for example, the arts or in history.

In this way there are rich opportunities for students to make links between their science and TOK courses. One way in which science teachers can help students to make these links to TOK is by drawing students’ attention to knowledge questions which arise from their subject content. Knowledge questions are open-ended questions about knowledge, and include questions such as:

• How do we distinguish science from pseudoscience?

• When performing experiments, what is the relationship between a scientist’s expectation and their perception?

• How does scientific knowledge progress?

• What is the role of imagination and intuition in the sciences?

• What are the similarities and differences in methods in the natural sciences and the human sciences?

Nature of biology

Biology guide 17

Examples of relevant knowledge questions are provided throughout this guide within the sub-topics in the syllabus content. Teachers can also find suggestions of interesting knowledge questions for discussion in the “Areas of knowledge” and “Knowledge frameworks” sections of the TOK guide. Students should be encouraged to raise and discuss such knowledge questions in both their science and TOK classes.

Biology guide1818

Introduction

Aims

Group 4 aimsThrough studying biology, chemistry or physics, students should become aware of how scientists work and communicate with each other. While the scientific method may take on a wide variety of forms, it is the emphasis on a practical approach through experimental work that characterizes these subjects.

The aims enable students, through the overarching theme of the Nature of science, to:

1. appreciate scientific study and creativity within a global context through stimulating and challenging opportunities

2. acquire a body of knowledge, methods and techniques that characterize science and technology

3. apply and use a body of knowledge, methods and techniques that characterize science and technology

4. develop an ability to analyse, evaluate and synthesize scientific information

5. develop a critical awareness of the need for, and the value of, effective collaboration and communication during scientific activities

6. develop experimental and investigative scientific skills including the use of current technologies

7. develop and apply 21st century communication skills in the study of science

8. become critically aware, as global citizens, of the ethical implications of using science and technology

9. develop an appreciation of the possibilities and limitations of science and technology

10. develop an understanding of the relationships between scientific disciplines and their influence on other areas of knowledge.

Biology guide 1919

Introduction

Assessment objectives

The assessment objectives for biology, chemistry and physics reflect those parts of the aims that will be formally assessed either internally or externally. These assessments will centre upon the nature of science. It is the intention of these courses that students are able to fulfill the following assessment objectives:

1. Demonstrate knowledge and understanding of:

a. facts, concepts and terminology

b. methodologies and techniques

c. communicating scientific information.

2. Apply:

a. facts, concepts and terminology


c. methods of communicating scientific information.

3. Formulate, analyse and evaluate:

a. hypotheses, research questions and predictions


c. primary and secondary data

d. scientific explanations.

4. Demonstrate the appropriate research, experimental, and personal skills necessary to carry out insightful and ethical investigations.

Biology guide2020

Syllabus

Syllabus outline

Syllabus componentTeaching hours

SL HL

Core1. Cell biology

2. Molecular biology

3. Genetics

4. Ecology

5. Evolution and biodiversity

6. Human physiology

9515

21

15

12

12

20

Additional higher level (AHL)7. Nucleic acids

8. Metabolism, cell respiration and photosynthesis

9. Plant biology

10. Genetics and evolution

11. Animal physiology

609

14

13

8

16

OptionA. Neurobiology and behaviour

B. Biotechnology and bioinformatics

C. Ecology and conservation

D. Human physiology

1515

15

15

15

2525

25

25

25

Practical scheme of workPractical activities

Individual investigation (internal assessment–IA)

Group 4 project

4020

10

10

6040

10

10

Total teaching hours 150 240

The recommended teaching time is 240 hours to complete HL and 150 hours to complete SL courses as stated in the document General regulations: Diploma Programme for students and their legal guardians (2011) (page 4, Article 8.2).

Biology guide 2121

Syllabus

Approaches to the teaching and learning of biology

Format of the syllabusThe format of the syllabus section of the group 4 guides is the same for physics, chemistry and biology. This new structure gives prominence and focus to the teaching and learning aspects.

Topics or optionsTopics are numbered and options are indicated by a letter. For example, “Topic 4: Ecology”, or “Option D: Human Physiology”.

Sub-topicsSub-topics are numbered as follows, “4.1: Species, communities and ecosystems”. Further information and guidance about possible teaching times are contained in the teacher support materials.

Each sub-topic begins with an essential idea. The essential idea is an enduring interpretation that is considered part of the public understanding of science. This is followed by a section on the “Nature of science”. This gives specific examples in context illustrating some aspects of the nature of science. These are linked directly to specific references in the “Nature of science” section of the guide to support teachers in their understanding of the general theme to be addressed.

Under the overarching Nature of science theme there are two columns. The f irst column lists “Understandings”, which are the main general ideas to be taught. There follows an “Applications and skills” section that outlines the specific applications and skills to be developed from the understandings. A “Guidance” section gives information about the limits and constraints and the depth of treatment required for teachers and examiners. The contents of the “Nature of science” section above the two columns and contents of the first column are all legitimate items for assessment. In addition, some assessment of international-mindedness in science, from the content of the second column, will take place as in the previous course.

The second column gives suggestion to teachers about relevant references to international-mindedness. It also gives examples of TOK knowledge questions (see Theory of knowledge guide published 2013) that can be used to focus students’ thoughts on the preparation of the TOK prescribed essay. The “Utilization” section may link the sub-topic to other parts of the subject syllabus, to other Diploma Programme subject guides or to real-world applications. Finally, the “Aims” section refers to how specific group 4 aims are being addressed in the sub-topic.


Biology guide22

Format of the guideTopic 1: <Title>

Essential idea: This lists the essential idea for each sub-topic.

1.1 Sub-topic

Nature of science: Relates the sub-topic to the overarching theme of Nature of science.

Understandings:

• This section will provide specifics of the content requirements for each sub-topic.

Applications and skills:

• The content of this section gives details of how students are to apply the understandings. For example, these applications could involve demonstrating mathematical calculations or practical skills.

Guidance:

• This section will provide specifics and give constraints to the requirements for the understandings and applications and skills.

International-mindedness:

• Ideas that teachers can easily integrate into the delivery of their lessons.

Theory of knowledge:

• Examples of TOK knowledge questions.

Utilization:

• Links to other topics within the Biology guide, to a variety of real-world applications and to other Diploma Programme courses.

Aims:

• Links to the group 4 subject aims.

Group 4 experimental skillsI hear and I forget. I see and I remember. I do and I understand.

Confucius

Integral to the experience of students in any of the group 4 courses is their experience in the classroom, laboratory or in the field. Practical activities allow students to interact directly with natural phenomena and secondary data sources. These experiences provide the students with the opportunity to design investigations, collect data, develop manipulative skills, analyse results, collaborate with peers and evaluate and communicate their findings. Experiments can be used to introduce a topic, investigate a phenomenon or allow students to consider and examine questions and curiosities.

By providing students with the opportunity for hands-on experimentation, they are carrying out some of the same processes that scientists undertake. Experimentation allows students to experience the nature of scientific thought and investigation. All scientific theories and laws begin with observations.

It is important that students are involved in an inquiry-based practical programme that allows for the development of scientific inquiry. It is not enough for students just to be able to follow directions and to simply replicate a given experimental procedure; they must be provided with the opportunities for genuine inquiry. Developing scientific inquiry skills will give students the ability to construct an explanation based on reliable evidence and logical reasoning. Once developed, these higher-order thinking skills will enable students to be lifelong learners and scientifically literate.

A school’s practical scheme of work should allow students to experience the full breadth and depth of the course including the option. This practical scheme of work must also prepare students to undertake


Biology guide 23

the independent investigation that is required for the internal assessment. The development of students’ manipulative skills should involve them being able to follow instructions accurately and demonstrate the safe, competent and methodical use of a range of techniques and equipment.

The “Applications and skills” section of the syllabus lists specific lab skills, techniques and experiments that students must experience at some point during their study of their group 4 course. Other recommended lab skills, techniques and experiments are listed in the “Aims” section of the subject-specific syllabus pages. Aim 6 of the group 4 subjects directly relates to the development of experimental and investigative skills.

Mathematical requirementsAll Diploma Programme biology students should be able to:

• perform the basic arithmetic functions: addition, subtraction, multiplication and division

• carry out calculations involving means, decimals, fractions, percentages and ratios

• represent and interpret frequency data in the form of bar charts, graphs and histograms, including direct and inverse proportion

• plot graphs (with suitable scales and axes) involving two variables that show linear or non-linear relationships

• plot and interpret scattergraphs to identify a correlation between two variables, and appreciate that the existence of a correlation does not establish a causal relationship

• determine the mode and median of a set of data, calculate and analyse standard deviation

• select statistical tests appropriate for the analysis of particular data and interpret the results.

Use of information communication technology The use of information communication technology (ICT) is encouraged throughout all aspects of the course in relation to both the practical programme and day-to-day classroom activities. Teachers should make use of the ICT pages of the teacher support materials.

Planning your courseThe syllabus as provided in the subject guide is not intended to be a teaching order. Instead it provides detail of what must be covered by the end of the course. A school should develop a scheme of work that best works for its students. For example, the scheme of work could be developed to match available resources, to take into account student prior learning and experience, or in conjunction with other local requirements.

HL teachers may choose to teach the core and AHL topics at the same time or teach them in a spiral fashion, by teaching the core topics in year one of the course and revisiting the core topics through the delivery of the AHL topics in year two of the course. The option topic could be taught as a stand-alone topic or could be integrated into the teaching of the core and/or AHL topics.

However the course is planned, adequate time must be provided for examination revision. Time must also be given for students to reflect on their learning experience and their growth as learners.


Biology guide24

The IB learner profile The biology course is closely linked to the IB learner profile. By following the course, students will have engaged with the attributes of the IB learner profile. For example, the requirements of the internal assessment provide opportunities for students to develop every aspect of the profile. For each attribute of the learner profile, a number of references from the Group 4 courses are given below.

Learner profile attribute

Biology, chemistry and physics

Inquirers Aims 2 and 6

Practical work and internal assessment

Knowledgeable Aims 1 and 10, international-mindedness links


Thinkers Aims 3 and 4, theory of knowledge links


Communicators Aims 5 and 7, external assessment


Principled Aims 8 and 9

Practical work and internal assessment. Ethical behaviour/practice (Ethical practice in the Diploma Programme poster, IB animal experimentation policy), academic honesty

Open-minded Aims 8 and 9, international-mindedness links

Practical work and internal assessment, the group 4 project

Caring Aims 8 and 9

Practical work and internal assessment, the group 4 project, ethical behaviour/practice (Ethical practice in the Diploma Programme poster, IB animal experimentation policy)

Risk-takers Aims 1 and 6


Balanced Aims 8 and 10

Practical work and internal assessment, the group 4 project and field work

Reflective Aims 5 and 9


Biology guide 2525

Syllabus

Syllabus content

Recommended teaching hours

Core 95 hours

Topic 1: Cell biology 15

1.1 Introduction to cells

1.2 Ultrastructure of cells

1.3 Membrane structure

1.4 Membrane transport

1.5 The origin of cells

1.6 Cell division

Topic 2: Molecular biology 21

2.1 Molecules to metabolism

2.2 Water

2.3 Carbohydrates and lipids

2.4 Proteins

2.5 Enzymes

2.6 Structure of DNA and RNA

2.7 DNA replication, transcription and translation

2.8 Cell respiration

2.9 Photosynthesis

Topic 3: Genetics 15

3.1 Genes

3.2 Chromosomes

3.3 Meiosis

3.4 Inheritance

3.5 Genetic modification and biotechnology

Syllabus content

Biology guide26


Topic 4: Ecology 12

4.1 Species, communities and ecosystems

4.2 Energy flow

4.3 Carbon cycling

4.4 Climate change

Topic 5: Evolution and biodiversity 12

5.1 Evidence for evolution

5.2 Natural selection

5.3 Classification of biodiversity

5.4 Cladistics

Topic 6: Human physiology 20

6.1 Digestion and absorption

6.2 The blood system

6.3 Defence against infectious disease

6.4 Gas exchange

6.5 Neurons and synapses

6.6 Hormones, homeostasis and reproduction

Additional higher level (AHL) 60 hours

Topic 7: Nucleic acids 9

7.1 DNA structure and replication

7.2 Transcription and gene expression

7.3 Translation

Topic 8: Metabolism, cell respiration and photosynthesis 14

8.1 Metabolism

8.2 Cell respiration

8.3 Photosynthesis

Topic 9: Plant biology 13

9.1 Transport in the xylem of plants

9.2 Transport in the phloem of plants

Syllabus content

Biology guide 27


9.3 Growth in plants

9.4 Reproduction in plants

Topic 10: Genetics and evolution 8

10.1 Meiosis

10.2 Inheritance

10.3 Gene pools and speciation

Topic 11: Animal physiology 16

11.1 Antibody production and vaccination

11.2 Movement

11.3 The kidney and osmoregulation

11.4 Sexual reproduction

Options 15 hours (SL)/25 hours (HL)

A: Neurobiology and behaviour

Core topics

A.1 Neural development

A.2 The human brain

A.3 Perception of stimuli

Additional higher level topics

A.4 Innate and learned behaviour

A.5 Neuropharmacology

A.6 Ethology

B: Biotechnology and bioinformatics

Core topics

B.1 Microbiology: organisms in industry

B.2 Biotechnology in agriculture

B.3 Environmental protection


B.4 Medicine

B.5 Bioinformatics

Syllabus content

Biology guide28

C: Ecology and conservation

Core topics

C.1 Species and communities

C.2 Communities and ecosystems

C.3 Impacts of humans on ecosystems

C.4 Conservation of biodiversity


C.5 Population ecology

C.6 Nitrogen and phosphorus cycles

D: Human physiology

Core topics

D.1 Human nutrition

D.2 Digestion

D.3 Functions of the liver

D.4 The heart


D.5 Hormones and metabolism

D.6 Transport of respiratory gases

29Biology guide 29

Core Topi

c 1:

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Topic 1: Cell biology

Biology guide30

1.1

Intr

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to c

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App

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gia

nt a

lgae

and

ase

ptat

e fu

ngal

hyp

hae.

• A

pplic

atio

n: In

vest

igat

ion

of fu

nctio

ns o

f life

in P

aram

eciu

m a

nd o

ne n

amed

ph

otos

ynth

etic

uni

cellu

lar o

rgan

ism

.

• A

pplic

atio

n: U

se o

f ste

m c

ells

to tr

eat S

targ

ardt

’s di

seas

e an

d on

e ot

her

nam

ed c

ondi

tion.

• A

pplic

atio

n: E

thic

s of

the

ther

apeu

tic u

se o

f ste

m c

ells

from

spe

cial

ly c

reat

ed

embr

yos,

from

the

umbi

lical

cor

d bl

ood

of a

new

-bor

n ba

by a

nd fr

om a

n ad

ult’s

ow

n tis

sues

.

• Sk

ill: U

se o

f a li

ght m

icro

scop

e to

inve

stig

ate

the

stru

ctur

e of

cel

ls a

nd

tissu

es, w

ith d

raw

ing

of c

ells

. Cal

cula

tion

of th

e m

agni

ficat

ion

of d

raw

ings

an

d th

e ac

tual

siz

e of

str

uctu

res

and

ultr

astr

uctu

res

show

n in

dra

win

gs o

r m

icro

grap

hs. (

Prac

tical

1)

Gui

danc

e:

• St

uden

ts a

re e

xpec

ted

to b

e ab

le to

nam

e an

d br

iefly

exp

lain

thes

e fu

nctio

ns

of li

fe: n

utrit

ion,

met

abol

ism

, gro

wth

, res

pons

e, e

xcre

tion,

hom

eost

asis

and

re

prod

uctio

n.

• Ch

lore

lla o

r Sce

nede

smus

are

sui

tabl

e ph

otos

ynth

etic

uni

cells

, but

Eug

lena

sh

ould

be

avoi

ded

as it

can

feed

het

erot

roph

ical

ly.

• Sc

ale

bars

are

use

ful a

s a

way

of i

ndic

atin

g ac

tual

siz

es in

dra

win

gs a

nd

mic

rogr

aphs

.

Aim

s:

• A

im 8

: The

re a

re e

thic

al is

sues

invo

lved

in s

tem

cel

l res

earc

h, w

heth

er

hum

ans

or o

ther

ani

mal

s ar

e us

ed. U

se o

f em

bryo

nic

stem

cel

ls in

volv

es

the

deat

h of

ear

ly-s

tage

em

bryo

s, b

ut if

ther

apeu

tic c

loni

ng is

suc

cess

fully

de

velo

ped

the

suff

erin

g of

pat

ient

s w

ith a

wid

e va

riety

of c

ondi

tions

cou

ld

be re

duce

d.


Biology guide 31

Esse

ntia

l ide

a: E

ukar

yote

s ha

ve a

muc

h m

ore

com

plex

cel

l str

uctu

re th

an p

roka

ryot

es.

1.2

Ult

rast

ruct

ure

of c

ells

Nat

ure

of s

cien

ce:

Dev

elop

men

ts in

sci

entif

ic re

sear

ch fo

llow

impr

ovem

ents

in a

ppar

atus

—th

e in

vent

ion

of e

lect

ron

mic

rosc

opes

led

to g

reat

er u

nder

stan

ding

of c

ell s

truc

ture

. (1.

8)

Und

erst

andi

ngs:

• Pr

okar

yote

s ha

ve a

sim

ple

cell

stru

ctur

e w

ithou

t com

part

men

taliz

atio

n.

• Eu

kary

otes

hav

e a

com

part

men

taliz

ed c

ell s

truc

ture

.

• El

ectr

on m

icro

scop

es h

ave

a m

uch

high

er re

solu

tion

than

ligh

t mic

rosc

opes

.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: S

truc

ture

and

func

tion

of o

rgan

elle

s w

ithin

exo

crin

e gl

and

cells

of

the

panc

reas

and

with

in p

alis

ade

mes

ophy

ll ce

lls o

f the

leaf

.

• A

pplic

atio

n: P

roka

ryot

es d

ivid

e by

bin

ary

fissi

on.

• Sk

ill: D

raw

ing

of th

e ul

tras

truc

ture

of p

roka

ryot

ic c

ells

bas

ed o

n el

ectr

on

mic

rogr

aphs

.

• Sk

ill: D

raw

ing

of th

e ul

tras

truc

ture

of e

ukar

yotic

cel

ls b

ased

on

elec

tron

m

icro

grap

hs.

• Sk

ill: I

nter

pret

atio

n of

ele

ctro

n m

icro

grap

hs to

iden

tify

orga

nelle

s an

d de

duce

the

func

tion

of s

peci

aliz

ed c

ells

.

Gui

danc

e:

• D

raw

ings

of p

roka

ryot

ic c

ells

sho

uld

show

the

cell

wal

l, pi

li an

d fla

gella

, and

pl

asm

a m

embr

ane

encl

osin

g cy

topl

asm

that

con

tain

s 70

S rib

osom

es a

nd a

nu

cleo

id w

ith n

aked

DN

A.

• D

raw

ings

of e

ukar

yotic

cel

ls s

houl

d sh

ow a

pla

sma

mem

bran

e en

clos

ing

cyto

plas

m th

at c

onta

ins

80S

ribos

omes

and

a n

ucle

us, m

itoch

ondr

ia a

nd

othe

r mem

bran

e-bo

und

orga

nelle

s ar

e pr

esen

t in

the

cyto

plas

m. S

ome

euka

ryot

ic c

ells

hav

e a

cell

wal

l.

Inte

rnat

iona

l-m

inde

dnes

s:

• M

icro

scop

es w

ere

inve

nted

sim

ulta

neou

sly

in d

iffer

ent p

arts

of t

he w

orld

at

a tim

e w

hen

info

rmat

ion

trav

elle

d sl

owly

. Mod

ern-

day

com

mun

icat

ions

hav

e al

low

ed fo

r im

prov

emen

ts in

the

abili

ty to

col

labo

rate

, enr

ichi

ng s

cien

tific

en

deav

our.

Theo

ry o

f kno

wle

dge:

• Th

e w

orld

that

we

inha

bit i

s lim

ited

by th

e w

orld

that

we

see.

Is th

ere

any

dist

inct

ion

to b

e dr

awn

betw

een

know

ledg

e cl

aim

s de

pend

ent u

pon

obse

rvat

ions

mad

e by

sen

se p

erce

ptio

n an

d kn

owle

dge

clai

ms

depe

nden

t up

on o

bser

vatio

ns a

ssis

ted

by te

chno

logy

?

Uti

lizat

ion:

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Ph

ysic

s To

pic

4.4

Wav

e be

havi

our

Topi

c C

.1 In

trod

uctio

n to

imag

ing

Topi

c C

.3 F

ibre

optic

s

Aim

s:

• A

im 8

: Dev

elop

men

ts in

sci

ence

, suc

h as

ele

ctro

n m

icro

scop

y, c

an h

ave

econ

omic

ben

efits

as

they

giv

e co

mm

erci

al c

ompa

nies

opp

ortu

nitie

s to

m

ake

prof

its, b

ut th

is c

an a

ffec

t coo

pera

tion

betw

een

scie

ntis

ts.


Biology guide32

Esse

ntia

l ide

a: T

he s

truc

ture

of b

iolo

gica

l mem

bran

es m

akes

them

flui

d an

d dy

nam

ic.

1.3

Mem

bran

e st

ruct

ure

Nat

ure

of s

cien

ce:

Usi

ng m

odel

s as

repr

esen

tatio

ns o

f the

real

wor

ld—

ther

e ar

e al

tern

ativ

e m

odel

s of

mem

bran

e st

ruct

ure.

(1.11

)

Fals

ifica

tion

of th

eorie

s w

ith o

ne th

eory

bei

ng s

uper

sede

d by

ano

ther

—ev

iden

ce fa

lsifi

ed th

e D

avso

n-D

anie

lli m

odel

. (1.

9)

Und

erst

andi

ngs:

• Ph

osph

olip

ids

form

bila

yers

in w

ater

due

to th

e am

phip

athi

c pr

oper

ties

of

phos

phol

ipid

mol

ecul

es.

• M

embr

ane

prot

eins

are

div

erse

in te

rms

of s

truc

ture

, pos

ition

in th

e m

embr

ane

and

func

tion.

• Ch

oles

tero

l is

a co

mpo

nent

of a

nim

al c

ell m

embr

anes

.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: C

hole

ster

ol in

mam

mal

ian

mem

bran

es re

duce

s m

embr

ane

fluid

ity a

nd p

erm

eabi

lity

to s

ome

solu

tes.

• Sk

ill: D

raw

ing

of th

e flu

id m

osai

c m

odel

.

• Sk

ill: A

naly

sis

of e

vide

nce

from

ele

ctro

n m

icro

scop

y th

at le

d to

the

prop

osal

of

the

Dav

son-

Dan

ielli

mod

el.

• Sk

ill: A

naly

sis

of th

e fa

lsifi

catio

n of

the

Dav

son-

Dan

ielli

mod

el th

at le

d to

the

Sing

er-N

icol

son

mod

el.

Gui

danc

e:

• A

mph

ipat

hic

phos

phol

ipid

s ha

ve h

ydro

phili

c an

d hy

drop

hobi

c pr

oper

ties.

• D

raw

ings

of t

he fl

uid

mos

aic

mod

el o

f mem

bran

e st

ruct

ure

can

be tw

o di

men

sion

al ra

ther

than

thre

e di

men

sion

al. I

ndiv

idua

l pho

spho

lipid

m

olec

ules

sho

uld

be s

how

n us

ing

the

sym

bol o

f a c

ircle

with

two

para

llel

lines

att

ache

d. A

rang

e of

mem

bran

e pr

otei

ns s

houl

d be

sho

wn

incl

udin

g gl

ycop

rote

ins.

Theo

ry o

f kno

wle

dge:

• Th

e ex

plan

atio

n of

the

stru

ctur

e of

the

plas

ma

mem

bran

e ha

s ch

ange

d ov

er

the

year

s as

new

evi

denc

e an

d w

ays

of a

naly

sis

have

com

e to

ligh

t. U

nder

w

hat c

ircum

stan

ces

is it

impo

rtan

t to

lear

n ab

out t

heor

ies

that

wer

e la

ter

disc

redi

ted?

Uti

lizat

ion:

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Bi

olog

yTo

pic

2.3

Carb

ohyd

rate

s an

d lip

ids

Topi

c 2.

6 St

ruct

ure

of D

NA

and

RN

A


Biology guide 33

Esse

ntia

l ide

a: M

embr

anes

con

trol

the

com

posi

tion

of c

ells

by

activ

e an

d pa

ssiv

e tr

ansp

ort.

1.4

Mem

bran

e tr

ansp

ort

Nat

ure

of s

cien

ce:

Expe

rimen

tal d

esig

n—ac

cura

te q

uant

itativ

e m

easu

rem

ent i

n os

mos

is e

xper

imen

ts a

re e

ssen

tial.

(3.1)

Und

erst

andi

ngs:

• Pa

rtic

les

mov

e ac

ross

mem

bran

es b

y si

mpl

e di

ffus

ion,

faci

litat

ed d

iffus

ion,

os

mos

is a

nd a

ctiv

e tr

ansp

ort.

• Th

e flu

idity

of m

embr

anes

allo

ws

mat

eria

ls to

be

take

n in

to c

ells

by

endo

cyto

sis

or re

leas

ed b

y ex

ocyt

osis

. Ves

icle

s m

ove

mat

eria

ls w

ithin

cel

ls.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: S

truc

ture

and

func

tion

of s

odiu

m–p

otas

sium

pum

ps fo

r act

ive

tran

spor

t and

pot

assi

um c

hann

els

for f

acili

tate

d di

ffus

ion

in a

xons

.

• A

pplic

atio

n: T

issu

es o

r org

ans

to b

e us

ed in

med

ical

pro

cedu

res

mus

t be

bath

ed in

a s

olut

ion

with

the

sam

e os

mol

arity

as

the

cyto

plas

m to

pre

vent

os

mos

is.

• Sk

ill: E

stim

atio

n of

osm

olar

ity in

tiss

ues

by b

athi

ng s

ampl

es in

hyp

oton

ic a

nd

hype

rton

ic s

olut

ions

. (Pr

actic

al 2

)

Gui

danc

e:

• O

smos

is e

xper

imen

ts a

re a

use

ful o

ppor

tuni

ty to

str

ess

the

need

for a

ccur

ate

mas

s an

d vo

lum

e m

easu

rem

ents

in s

cien

tific

exp

erim

ents

.

Uti

lizat

ion:

• Ki

dney

dia

lysi

s ar

tific

ially

mim

ics

the

func

tion

of th

e hu

man

kid

ney

by u

sing

ap

prop

riate

mem

bran

es a

nd d

iffus

ion

grad

ient

s.

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Bi

olog

yTo

pic

6.5

Neu

rons

and

syn

apse

s

Aim

s:

• A

im 8

: Org

an d

onat

ion

rais

es s

ome

inte

rest

ing

ethi

cal i

ssue

s, in

clud

ing

the

altr

uist

ic n

atur

e of

org

an d

onat

ion

and

conc

erns

abo

ut s

ale

of h

uman

org

ans.

• A

im 6

: Dia

lysi

s tu

bing

exp

erim

ents

can

act

as

a m

odel

of m

embr

ane

actio

n.

Expe

rimen

ts w

ith p

otat

o, b

eetr

oot o

r sin

gle-

celle

d al

gae

can

be u

sed

to

inve

stig

ate

real

mem

bran

es.


Biology guide34

Esse

ntia

l ide

a: T

here

is a

n un

brok

en c

hain

of l

ife fr

om th

e fir

st c

ells

on

Eart

h to

all

cells

in o

rgan

ism

s al

ive

toda

y.

1.5

The

orig

in o

f cel

ls

Nat

ure

of s

cien

ce:

Test

ing

the

gene

ral p

rinci

ples

that

und

erlie

the

natu

ral w

orld

—th

e pr

inci

ple

that

cel

ls o

nly

com

e fr

om p

re-e

xist

ing

cells

nee

ds to

be

verif

ied.

(1.9

)

Und

erst

andi

ngs:

• Ce

lls c

an o

nly

be fo

rmed

by

divi

sion

of p

re-e

xist

ing

cells

.

• Th

e fir

st c

ells

mus

t hav

e ar

isen

from

non

-livi

ng m

ater

ial.

• Th

e or

igin

of e

ukar

yotic

cel

ls c

an b

e ex

plai

ned

by th

e en

dosy

mbi

otic

theo

ry.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: E

vide

nce

from

Pas

teur

’s ex

perim

ents

that

spo

ntan

eous

ge

nera

tion

of c

ells

and

org

anis

ms

does

not

now

occ

ur o

n Ea

rth.

Gui

danc

e:

• Ev

iden

ce fo

r the

end

osym

biot

ic th

eory

is e

xpec

ted.

The

orig

in o

f euk

aryo

te

cilia

and

flag

ella

doe

s no

t nee

d to

be

incl

uded

.

• St

uden

ts s

houl

d be

aw

are

that

the

64 c

odon

s in

the

gene

tic c

ode

have

th

e sa

me

mea

ning

s in

nea

rly a

ll or

gani

sms,

but

that

ther

e ar

e so

me

min

or

varia

tions

that

are

like

ly to

hav

e ac

crue

d si

nce

the

com

mon

orig

in o

f life

on

Eart

h.

Theo

ry o

f kno

wle

dge:

• Bi

olog

y is

the

stud

y of

life

, yet

life

is a

n em

erge

nt p

rope

rty.

Und

er w

hat

circ

umst

ance

s is

a s

yste

ms

appr

oach

pro

duct

ive

in b

iolo

gy a

nd u

nder

w

hat c

ircum

stan

ces

is a

redu

ctio

nist

app

roac

h m

ore

appr

opria

te?

How

do

scie

ntis

ts d

ecid

e be

twee

n co

mpe

ting

appr

oach

es?

Uti

lizat

ion:

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Bi

olog

y To

pic

5.1

Evid

ence

for e

volu

tion

Aim

s:

• A

im 6

: Pas

teur

’s ex

perim

ent c

an b

e re

peat

ed u

sing

mod

ern

appa

ratu

s.


Biology guide 35

Esse

ntia

l ide

a: C

ell d

ivis

ion

is e

ssen

tial b

ut m

ust b

e co

ntro

lled.

1.6

Cell

divi

sion

Nat

ure

of s

cien

ce:

Sere

ndip

ity a

nd s

cien

tific

dis

cove

ries—

the

disc

over

y of

cyc

lins

was

acc

iden

tal.

(1.4

)

Und

erst

andi

ngs:

• M

itosi

s is d

ivis

ion

of th

e nu

cleu

s int

o tw

o ge

netic

ally

iden

tical

dau

ghte

r nuc

lei.

• Ch

rom

osom

es c

onde

nse

by s

uper

coili

ng d

urin

g m

itosi

s.

• Cy

toki

nesi

s oc

curs

aft

er m

itosi

s an

d is

diff

eren

t in

plan

t and

ani

mal

cel

ls.

• In

terp

hase

is a

ver

y ac

tive

phas

e of

the

cell

cycl

e w

ith m

any

proc

esse

s oc

curr

ing

in th

e nu

cleu

s an

d cy

topl

asm

.

• Cy

clin

s ar

e in

volv

ed in

the

cont

rol o

f the

cel

l cyc

le.

• M

utag

ens,

onc

ogen

es a

nd m

etas

tasi

s ar

e in

volv

ed in

the

deve

lopm

ent o

f pr

imar

y an

d se

cond

ary

tum

ours

.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: T

he c

orre

latio

n be

twee

n sm

okin

g an

d in

cide

nce

of c

ance

rs.

• Sk

ill: I

dent

ifica

tion

of p

hase

s of

mito

sis

in c

ells

vie

wed

with

a m

icro

scop

e or

in

a m

icro

grap

h.

• Sk

ill: D

eter

min

atio

n of

a m

itotic

inde

x fr

om a

mic

rogr

aph.

Gui

danc

e:

• Th

e se

quen

ce o

f eve

nts

in th

e fo

ur p

hase

s of

mito

sis

shou

ld b

e kn

own.

• Pr

epar

atio

n of

tem

pora

ry m

ount

s of

root

squ

ashe

s is

reco

mm

ende

d bu

t ph

ases

in m

itosi

s ca

n al

so b

e vi

ewed

usi

ng p

erm

anen

t slid

es.

• To

avo

id c

onfu

sion

in te

rmin

olog

y, te

ache

rs a

re e

ncou

rage

d to

refe

r to

the

two

part

s of

a c

hrom

osom

e as

sis

ter c

hrom

atid

s, w

hile

they

are

att

ache

d to

ea

ch o

ther

by

a ce

ntro

mer

e in

the

early

sta

ges

of m

itosi

s. F

rom

ana

phas

e on

war

ds, w

hen

sist

er c

hrom

atid

s ha

ve s

epar

ated

to fo

rm in

divi

dual

st

ruct

ures

, the

y sh

ould

be

refe

rred

to a

s ch

rom

osom

es.

Inte

rnat

iona

l-m

inde

dnes

s:

• Bi

olog

ists

in la

bora

torie

s th

roug

hout

the

wor

ld a

re re

sear

chin

g in

to th

e ca

uses

and

trea

tmen

t of c

ance

r.

Theo

ry o

f kno

wle

dge:

• A

num

ber o

f sci

entif

ic d

isco

verie

s ar

e cl

aim

ed to

be

inci

dent

al o

r se

rend

ipito

us. T

o w

hat e

xten

t mig

ht s

ome

of th

ese

scie

ntifi

c di

scov

erie

s be

th

e re

sult

of in

tuiti

on ra

ther

than

luck

?

Uti

lizat

ion:

• Th

e m

itotic

inde

x is

an

impo

rtan

t pro

gnos

tic to

ol fo

r pre

dict

ing

the

resp

onse

of

can

cer c

ells

to c

hem

othe

rapy

.

Aim

s:

• A

im 8

: The

toba

cco

indu

stry

cou

ld b

e di

scus

sed.

Sup

pres

sion

of t

he re

sults

of

rese

arch

by

toba

cco

com

pani

es in

to th

e he

alth

eff

ects

of s

mok

ing

toba

cco

was

une

thic

al. S

mok

ing

caus

es c

onsi

dera

ble

soci

al h

arm

, but

, with

the

exce

ptio

n of

law

s on

pro

duct

ion

and

supp

ly in

Bhu

tan,

has

nev

er b

een

mad

e ill

egal

.

Biology guide36

Core Topi

c 2:

Mol

ecul

ar b

iolo

gy

21 h

ours

Esse

ntia

l ide

a: L

ivin

g or

gani

sms

cont

rol t

heir

com

posi

tion

by a

com

plex

web

of c

hem

ical

reac

tions

.

2.1

Mol

ecul

es to

met

abol

ism

Nat

ure

of s

cien

ce:

Fals

ifica

tion

of th

eorie

s—th

e ar

tific

ial s

ynth

esis

of u

rea

help

ed to

fals

ify v

italis

m. (

1.9)

Und

erst

andi

ngs:

• M

olec

ular

bio

logy

exp

lain

s liv

ing

proc

esse

s in

term

s of

the

chem

ical

su

bsta

nces

invo

lved

.

• Ca

rbon

ato

ms

can

form

four

cov

alen

t bon

ds a

llow

ing

a di

vers

ity o

f sta

ble

com

poun

ds to

exi

st.

• Li

fe is

bas

ed o

n ca

rbon

com

poun

ds in

clud

ing

carb

ohyd

rate

s, li

pids

, pro

tein

s an

d nu

clei

c ac

ids.

• M

etab

olis

m is

the

web

of a

ll th

e en

zym

e-ca

taly

sed

reac

tions

in a

cel

l or

orga

nism

.

• A

nabo

lism

is th

e sy

nthe

sis

of c

ompl

ex m

olec

ules

from

sim

pler

mol

ecul

es

incl

udin

g th

e fo

rmat

ion

of m

acro

mol

ecul

es fr

om m

onom

ers

by c

onde

nsat

ion

reac

tions

.

• Ca

tabo

lism

is th

e br

eakd

own

of c

ompl

ex m

olec

ules

into

sim

pler

mol

ecul

es

incl

udin

g th

e hy

drol

ysis

of m

acro

mol

ecul

es in

to m

onom

ers.

Uti

lizat

ion:

Sylla

bus

and

cros

s-cu

rric

ular

link

s: Ch

emis

try

To

pic

4 Ch

emic

al b

ondi

ng a

nd s

truc

ture

O

ptio

n B

Bioc

hem

istr

y

Aim

s:

• A

im 7

: IC

T ca

n be

use

d fo

r mol

ecul

ar v

isua

lizat

ion

of c

arbo

hydr

ates

, lip

ids

and

prot

eins

in th

is s

ub-t

opic

and

in 2

.3 a

nd 2

.4.

• A

im 6

: Foo

d te

sts

such

as

the

use

of io

dine

to id

entif

y st

arch

or B

ened

ict’s

re

agen

t to

iden

tify

redu

cing

sug

ars

coul

d be

car

ried

out.

Topic 2: Molecular biology

Biology guide 37

2.1

Mol

ecul

es to

met

abol

ism

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: U

rea

as a

n ex

ampl

e of

a c

ompo

und

that

is p

rodu

ced

by li

ving

or

gani

sms

but c

an a

lso

be a

rtifi

cial

ly s

ynth

esiz

ed.

• Sk

ill: D

raw

ing

mol

ecul

ar d

iagr

ams

of g

luco

se, r

ibos

e, a

sat

urat

ed fa

tty

acid

an

d a

gene

raliz

ed a

min

o ac

id.

• Sk

ill: I

dent

ifica

tion

of b

ioch

emic

als

such

as

suga

rs, l

ipid

s or

am

ino

acid

s fr

om

mol

ecul

ar d

iagr

ams.

Gui

danc

e:

• O

nly

the

ring

form

s of

D-r

ibos

e, a

lpha

–D-g

luco

se a

nd b

eta-

D-g

luco

se a

re

expe

cted

in d

raw

ings

.

• Su

gars

incl

ude

mon

osac

char

ides

and

dis

acch

arid

es.

• O

nly

one

satu

rate

d fa

t is

expe

cted

and

its

spec

ific

nam

e is

not

nec

essa

ry.

• Th

e va

riabl

e ra

dica

l of a

min

o ac

ids

can

be s

how

n as

R. T

he s

truc

ture

of

indi

vidu

al R

-gro

ups

does

not

nee

d to

be

mem

oriz

ed.

• St

uden

ts s

houl

d be

abl

e to

reco

gniz

e fr

om m

olec

ular

dia

gram

s th

at

trig

lyce

rides

, pho

spho

lipid

s an

d st

eroi

ds a

re li

pids

. Dra

win

gs o

f ste

roid

s ar

e no

t exp

ecte

d.

• Pr

otei

ns o

r par

ts o

f pol

ypep

tides

sho

uld

be re

cogn

ized

from

mol

ecul

ar

diag

ram

s sh

owin

g am

ino

acid

s lin

ked

by p

eptid

e bo

nds.


Biology guide38

Esse

ntia

l ide

a: W

ater

is th

e m

ediu

m o

f life

.

2.2

Wat

er

Nat

ure

of s

cien

ce:

Use

theo

ries

to e

xpla

in n

atur

al p

heno

men

a—th

e th

eory

that

hyd

roge

n bo

nds

form

bet

wee

n w

ater

mol

ecul

es e

xpla

ins

the

prop

ertie

s of

wat

er. (

2.2)

Und

erst

andi

ngs:

• W

ater

mol

ecul

es a

re p

olar

and

hyd

roge

n bo

nds

form

bet

wee

n th

em.

• H

ydro

gen

bond

ing

and

dipo

larit

y ex

plai

n th

e co

hesi

ve, a

dhes

ive,

ther

mal

an

d so

lven

t pro

pert

ies

of w

ater

.

• Su

bsta

nces

can

be

hydr

ophi

lic o

r hyd

roph

obic

.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: C

ompa

rison

of t

he th

erm

al p

rope

rtie

s of

wat

er w

ith th

ose

of

met

hane

.

• A

pplic

atio

n: U

se o

f wat

er a

s a

cool

ant i

n sw

eat.

• A

pplic

atio

n: M

odes

of t

rans

port

of g

luco

se, a

min

o ac

ids,

cho

lest

erol

, fat

s,

oxyg

en a

nd s

odiu

m c

hlor

ide

in b

lood

in re

latio

n to

thei

r sol

ubili

ty in

wat

er.

Gui

danc

e:

• St

uden

ts s

houl

d kn

ow a

t lea

st o

ne e

xam

ple

of a

ben

efit

to li

ving

org

anis

ms

of e

ach

prop

erty

of w

ater

.

• Tr

ansp

aren

cy o

f wat

er a

nd m

axim

um d

ensi

ty a

t 4°C

do

not n

eed

to b

e in

clud

ed.

• Co

mpa

rison

of t

he th

erm

al p

rope

rtie

s of

wat

er a

nd m

etha

ne a

ssis

ts in

the

unde

rsta

ndin

g of

the

sign

ifica

nce

of h

ydro

gen

bond

ing

in w

ater

.

Inte

rnat

iona

l-m

inde

dnes

s:

• Th

ere

are

chal

leng

es fo

r the

incr

easi

ng h

uman

pop

ulat

ion

in s

harin

g w

ater

re

sour

ces

equi

tabl

y fo

r drin

king

and

irrig

atio

n, e

lect

ricity

gen

erat

ion

and

a ra

nge

of in

dust

rial a

nd d

omes

tic p

roce

sses

.

Theo

ry o

f kno

wle

dge:

• Cl

aim

s ab

out t

he “m

emor

y of

wat

er” h

ave

been

cat

egor

ized

as

pseu

dosc

ient

ific.

Wha

t are

the

crite

ria th

at c

an b

e us

ed to

dis

tingu

ish

scie

ntifi

c cl

aim

s fr

om p

seud

osci

entif

ic c

laim

s?

Uti

lizat

ion:

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Bi

olog

y To

pic

4.3

Carb

on c

yclin

gTo

pic

4.4

Clim

ate

chan

gePh

ysic

s To

pic

3.1

Ther

mal

con

cept

s

Aim

s:

• A

im 6

: Pro

bes

can

be u

sed

to d

eter

min

e th

e ef

fect

of d

iffer

ent f

acto

rs li

kely

to

influ

ence

coo

ling

with

wat

er.


Biology guide 39

Esse

ntia

l ide

a: C

ompo

unds

of c

arbo

n, h

ydro

gen

and

oxyg

en a

re u

sed

to s

uppl

y an

d st

ore

ener

gy.

2.3

Carb

ohyd

rate

s an

d lip

ids

Nat

ure

of s

cien

ce:

Eval

uatin

g cl

aim

s—he

alth

cla

ims

mad

e ab

out l

ipid

s in

die

ts n

eed

to b

e as

sess

ed. (

5.2)

Und

erst

andi

ngs:

• M

onos

acch

arid

e m

onom

ers

are

linke

d to

geth

er b

y co

nden

satio

n re

actio

ns to

fo

rm d

isac

char

ides

and

pol

ysac

char

ide

poly

mer

s.

• Fa

tty

acid

s ca

n be

sat

urat

ed, m

onou

nsat

urat

ed o

r pol

yuns

atur

ated

.

• U

nsat

urat

ed fa

tty

acid

s ca

n be

cis

or t

rans

isom

ers.

• Tr

igly

cerid

es a

re fo

rmed

by

cond

ensa

tion

from

thre

e fa

tty

acid

s and

one

gly

cero

l.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: S

truc

ture

and

func

tion

of c

ellu

lose

and

sta

rch

in p

lant

s an

d gl

ycog

en in

hum

ans.

• A

pplic

atio

n: S

cien

tific

evi

denc

e fo

r hea

lth ri

sks

of tr

ans

fats

and

sat

urat

ed

fatt

y ac

ids.

• A

pplic

atio

n: L

ipid

s ar

e m

ore

suita

ble

for l

ong-

term

ene

rgy

stor

age

in h

uman

s th

an c

arbo

hydr

ates

.

• A

pplic

atio

n: E

valu

atio

n of

evi

denc

e an

d th

e m

etho

ds u

sed

to o

btai

n th

e ev

iden

ce fo

r hea

lth c

laim

s m

ade

abou

t lip

ids.

• Sk

ill: U

se o

f mol

ecul

ar v

isua

lizat

ion

soft

war

e to

com

pare

cel

lulo

se, s

tarc

h an

d gl

ycog

en.

• Sk

ill: D

eter

min

atio

n of

bod

y m

ass

inde

x by

cal

cula

tion

or u

se o

f a n

omog

ram

.

Gui

danc

e:

• Th

e st

ruct

ure

of s

tarc

h sh

ould

incl

ude

amyl

ose

and

amyl

opec

tin.

• N

amed

exa

mpl

es o

f fat

ty a

cids

are

not

requ

ired.

• Su

cros

e, la

ctos

e an

d m

alto

se s

houl

d be

incl

uded

as

exam

ples

of

disa

ccha

rides

pro

duce

d by

com

bini

ng m

onos

acch

arid

es.

Inte

rnat

iona

l-m

inde

dnes

s:

• Va

riatio

n in

the

prev

alen

ce o

f diff

eren

t hea

lth p

robl

ems

arou

nd th

e w

orld

co

uld

be d

iscu

ssed

incl

udin

g ob

esity

, die

tary

ene

rgy

defic

ienc

y, k

was

hior

kor,

anor

exia

ner

vosa

and

cor

onar

y he

art d

isea

se.

Theo

ry o

f kno

wle

dge:

• Th

ere

are

conf

lictin

g vi

ews

as to

the

harm

s an

d be

nefit

s of

fats

in d

iets

. How

do

we

deci

de b

etw

een

com

petin

g vi

ews?

Uti

lizat

ion:

• Po

tato

es h

ave

been

gen

etic

ally

mod

ified

to re

duce

the

leve

l of a

myl

ose

to

prod

uce

a m

ore

effe

ctiv

e ad

hesi

ve.

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Bi

olog

yO

ptio

n B:

Bio

tech

nolo

gy a

nd b

ioin

form

atic

s

Aim

s:

• A

im 8

: The

re a

re s

ocia

l im

plic

atio

ns o

f obe

sity

.


Biology guide40

Esse

ntia

l ide

a: P

rote

ins

have

a v

ery

wid

e ra

nge

of fu

nctio

ns in

livi

ng o

rgan

ism

s.

2.4

Prot

eins

Nat

ure

of s

cien

ce:

Look

ing

for p

atte

rns,

tren

ds a

nd d

iscr

epan

cies

—m

ost b

ut n

ot a

ll or

gani

sms

asse

mbl

e pr

otei

ns fr

om th

e sa

me

amin

o ac

ids.

(3.1)

Und

erst

andi

ngs:

• A

min

o ac

ids

are

linke

d to

geth

er b

y co

nden

satio

n to

form

pol

ypep

tides

.

• Th

ere

are

20 d

iffer

ent a

min

o ac

ids

in p

olyp

eptid

es s

ynth

esiz

ed o

n rib

osom

es.

• A

min

o ac

ids

can

be li

nked

toge

ther

in a

ny s

eque

nce

givi

ng a

hug

e ra

nge

of

poss

ible

pol

ypep

tides

.

• Th

e am

ino

acid

seq

uenc

e of

pol

ypep

tides

is c

oded

for b

y ge

nes.

• A

pro

tein

may

con

sist

of a

sin

gle

poly

pept

ide

or m

ore

than

one

pol

ypep

tide

linke

d to

geth

er.

• Th

e am

ino

acid

seq

uenc

e de

term

ines

the

thre

e-di

men

sion

al c

onfo

rmat

ion

of

a pr

otei

n.

• Li

ving

org

anis

ms

synt

hesi

ze m

any

diff

eren

t pro

tein

s w

ith a

wid

e ra

nge

of

func

tions

.

• Ev

ery

indi

vidu

al h

as a

uni

que

prot

eom

e.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: R

ubis

co, i

nsul

in, i

mm

unog

lobu

lins,

rhod

opsi

n, c

olla

gen

and

spid

er s

ilk a

s ex

ampl

es o

f the

rang

e of

pro

tein

func

tions

.

• A

pplic

atio

n: D

enat

urat

ion

of p

rote

ins

by h

eat o

r by

devi

atio

n of

pH

from

the

optim

um.

• Sk

ill: D

raw

ing

mol

ecul

ar d

iagr

ams

to s

how

the

form

atio

n of

a p

eptid

e bo

nd.

Uti

lizat

ion:

• Pr

oteo

mic

s an

d th

e pr

oduc

tion

of p

rote

ins

by c

ells

cul

ture

d in

ferm

ente

rs

offe

r man

y op

port

uniti

es fo

r the

food

, pha

rmac

eutic

al a

nd o

ther

indu

strie

s.

Aim

s:

• A

im 7

: IC

T ca

n be

use

d fo

r mol

ecul

ar v

isua

lizat

ion

of th

e st

ruct

ure

of

prot

eins

.

• A

im 8

: Obt

aini

ng s

ampl

es o

f hum

an b

lood

for i

mm

unol

ogic

al,

phar

mac

eutic

al a

nd a

nthr

opol

ogic

al s

tudi

es is

an

inte

rnat

iona

l end

eavo

ur

with

man

y et

hica

l iss

ues.


Biology guide 41

2.4

Prot

eins

Gui

danc

e:

• Th

e de

taile

d st

ruct

ure

of th

e si

x pr

otei

ns s

elec

ted

to il

lust

rate

the

func

tions

of

pro

tein

s is

not

nee

ded.

• Eg

g w

hite

or a

lbum

in s

olut

ions

can

be

used

in d

enat

urat

ion

expe

rimen

ts.

• St

uden

ts s

houl

d kn

ow th

at m

ost o

rgan

ism

s us

e th

e sa

me

20 a

min

o ac

ids

in th

e sa

me

gene

tic c

ode

alth

ough

ther

e ar

e so

me

exce

ptio

ns. S

peci

fic

exam

ples

cou

ld b

e us

ed fo

r illu

stra

tion.


Biology guide42

Esse

ntia

l ide

a: E

nzym

es c

ontr

ol th

e m

etab

olis

m o

f the

cel

l.

2.5

Enzy

mes

Nat

ure

of s

cien

ce:

Expe

rimen

tal d

esig

n—ac

cura

te, q

uant

itativ

e m

easu

rem

ents

in e

nzym

e ex

perim

ents

requ

ire re

plic

ates

to e

nsur

e re

liabi

lity.

(3.2

)

Und

erst

andi

ngs:

• En

zym

es h

ave

an a

ctiv

e si

te to

whi

ch s

peci

fic s

ubst

rate

s bi

nd.

• En

zym

e ca

taly

sis

invo

lves

mol

ecul

ar m

otio

n an

d th

e co

llisi

on o

f sub

stra

tes

with

the

activ

e si

te.

• Te

mpe

ratu

re, p

H a

nd s

ubst

rate

con

cent

ratio

n af

fect

the

rate

of a

ctiv

ity o

f en

zym

es.

• En

zym

es c

an b

e de

natu

red.

• Im

mob

ilize

d en

zym

es a

re w

idel

y us

ed in

indu

stry

.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: M

etho

ds o

f pro

duct

ion

of la

ctos

e-fr

ee m

ilk a

nd it

s ad

vant

ages

.

• Sk

ill: D

esig

n of

exp

erim

ents

to te

st th

e ef

fect

of t

empe

ratu

re, p

H a

nd

subs

trat

e co

ncen

trat

ion

on th

e ac

tivity

of e

nzym

es.

• Sk

ill: E

xper

imen

tal i

nves

tigat

ion

of a

fact

or a

ffec

ting

enzy

me

activ

ity.

(Pra

ctic

al 3

)

Gui

danc

e:

• La

ctas

e ca

n be

imm

obili

zed

in a

lgin

ate

bead

s an

d ex

perim

ents

can

then

be

carr

ied

out i

n w

hich

the

lact

ose

in m

ilk is

hyd

roly

sed.

• St

uden

ts s

houl

d be

abl

e to

ske

tch

grap

hs to

sho

w th

e ex

pect

ed e

ffec

ts o

f te

mpe

ratu

re, p

H a

nd s

ubst

rate

con

cent

ratio

n on

the

activ

ity o

f enz

ymes

. Th

ey s

houl

d be

abl

e to

exp

lain

the

patt

erns

or t

rend

s ap

pare

nt in

thes

e gr

aphs

.

Theo

ry o

f kno

wle

dge:

• D

evel

opm

ent o

f som

e te

chni

ques

ben

efits

par

ticul

ar h

uman

pop

ulat

ions

m

ore

than

oth

ers.

For

exa

mpl

e, th

e de

velo

pmen

t of l

acto

se-f

ree

milk

av

aila

ble

in E

urop

e an

d N

orth

Am

eric

a w

ould

hav

e gr

eate

r ben

efit

in A

fric

a/A

sia

whe

re la

ctos

e in

tole

ranc

e is

mor

e pr

eval

ent.

The

deve

lopm

ent o

f te

chni

ques

requ

ires

finan

cial

inve

stm

ent.

Shou

ld k

now

ledg

e be

sha

red

whe

n te

chni

ques

dev

elop

ed in

one

par

t of t

he w

orld

are

mor

e ap

plic

able

in

anot

her?

Uti

lizat

ion:

• En

zym

es a

re e

xten

sive

ly u

sed

in in

dust

ry fo

r the

pro

duct

ion

of it

ems

from

fr

uit j

uice

to w

ashi

ng p

owde

r.

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Bi

olog

y To

pic

8 A

HL

Met

abol

ism

, cel

l res

pira

tion

and

phot

osyn

thes

is


Biology guide 43

Esse

ntia

l ide

a: T

he s

truc

ture

of D

NA

allo

ws

effic

ient

sto

rage

of g

enet

ic in

form

atio

n.

2.6

Stru

ctur

e of

DN

A a

nd R

NA

Nat

ure

of s

cien

ce:

Usi

ng m

odel

s as

repr

esen

tatio

n of

the

real

wor

ld—

Cric

k an

d W

atso

n us

ed m

odel

mak

ing

to d

isco

ver t

he s

truc

ture

of D

NA

. (1.

10)

Und

erst

andi

ngs:

• Th

e nu

clei

c ac

ids

DN

A a

nd R

NA

are

pol

ymer

s of

nuc

leot

ides

.

• D

NA

diff

ers

from

RN

A in

the

num

ber o

f str

ands

pre

sent

, the

bas

e co

mpo

sitio

n an

d th

e ty

pe o

f pen

tose

.

• D

NA

is a

dou

ble

helix

mad

e of

two

antip

aral

lel s

tran

ds o

f nuc

leot

ides

link

ed

by h

ydro

gen

bond

ing

betw

een

com

plem

enta

ry b

ase

pairs

.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: C

rick

and

Wat

son’

s el

ucid

atio

n of

the

stru

ctur

e of

DN

A u

sing

m

odel

mak

ing.

• Sk

ill: D

raw

ing

sim

ple

diag

ram

s of

the

stru

ctur

e of

sin

gle

nucl

eotid

es o

f DN

A

and

RNA

, usi

ng c

ircle

s, p

enta

gons

and

rect

angl

es to

repr

esen

t pho

spha

tes,

pe

ntos

es a

nd b

ases

.

Gui

danc

e:

• In

dia

gram

s of

DN

A s

truc

ture

, the

hel

ical

sha

pe d

oes

not n

eed

to b

e sh

own,

bu

t the

two

stra

nds

shou

ld b

e sh

own

antip

aral

lel.

Ade

nine

sho

uld

be s

how

n pa

ired

with

thym

ine

and

guan

ine

with

cyt

osin

e, b

ut th

e re

lativ

e le

ngth

s of

th

e pu

rine

and

pyrim

idin

e ba

ses

do n

ot n

eed

to b

e re

calle

d, n

or th

e nu

mbe

rs

of h

ydro

gen

bond

s be

twee

n th

e ba

se p

airs

.

Theo

ry o

f kno

wle

dge:

• Th

e st

ory

of th

e el

ucid

atio

n of

the

stru

ctur

e of

DN

A il

lust

rate

s th

at

coop

erat

ion

and

colla

bora

tion

amon

g sc

ient

ists

exi

sts

alon

gsid

e co

mpe

titio

n be

twee

n re

sear

ch g

roup

s. T

o w

hat e

xten

t is

rese

arch

in s

ecre

t ‘an

ti-sc

ient

ific’

? W

hat i

s th

e re

latio

nshi

p be

twee

n sh

ared

and

per

sona

l kno

wle

dge

in th

e na

tura

l sci

ence

s?

Uti

lizat

ion:

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Bi

olog

y To

pic

2.2

Wat

er

Topi

c 3.

5 G

enet

ic m

odifi

catio

n an

d bi

otec

hnol

ogy

Topi

c 7

Nuc

leic

aci

ds


Biology guide44

Esse

ntia

l Ide

a: G

enet

ic in

form

atio

n in

DN

A c

an b

e ac

cura

tely

cop

ied

and

can

be tr

ansl

ated

to m

ake

the

prot

eins

nee

ded

by th

e ce

ll.

2.7

DN

A re

plic

atio

n, tr

ansc

ript

ion

and

tran

slat

ion

Nat

ure

of s

cien

ce:

Obt

aini

ng e

vide

nce

for s

cien

tific

theo

ries—

Mes

elso

n an

d St

ahl o

btai

ned

evid

ence

for t

he s

emi-c

onse

rvat

ive

repl

icat

ion

of D

NA

. (1.

8)

Und

erst

andi

ngs:

• Th

e re

plic

atio

n of

DN

A is

sem

i-con

serv

ativ

e an

d de

pend

s on

com

plem

enta

ry

base

pai

ring.

• H

elic

ase

unw

inds

the

doub

le h

elix

and

sep

arat

es th

e tw

o st

rand

s by

bre

akin

g hy

drog

en b

onds

.

• D

NA

pol

ymer

ase

links

nuc

leot

ides

toge

ther

to fo

rm a

new

str

and,

usi

ng th

e pr

e-ex

istin

g st

rand

as

a te

mpl

ate.

• Tr

ansc

riptio

n is

the

synt

hesi

s of

mRN

A c

opie

d fr

om th

e D

NA

bas

e se

quen

ces

by R

NA

pol

ymer

ase.

• Tr

ansl

atio

n is

the

synt

hesi

s of

pol

ypep

tides

on

ribos

omes

.

• Th

e am

ino

acid

seq

uenc

e of

pol

ypep

tides

is d

eter

min

ed b

y m

RNA

acc

ordi

ng

to th

e ge

netic

cod

e.

• Co

dons

of t

hree

bas

es o

n m

RNA

cor

resp

ond

to o

ne a

min

o ac

id in

a

poly

pept

ide.

• Tr

ansl

atio

n de

pend

s on

com

plem

enta

ry b

ase

pairi

ng b

etw

een

codo

ns o

n m

RNA

and

ant

icod

ons

on tR

NA

.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: U

se o

f Taq

DN

A p

olym

eras

e to

pro

duce

mul

tiple

cop

ies

of D

NA

ra

pidl

y by

the

poly

mer

ase

chai

n re

actio

n (P

CR).

• A

pplic

atio

n: P

rodu

ctio

n of

hum

an in

sulin

in b

acte

ria a

s an

exa

mpl

e of

the

univ

ersa

lity

of th

e ge

netic

cod

e al

low

ing

gene

tran

sfer

bet

wee

n sp

ecie

s.

• Sk

ill: U

se a

tabl

e of

the

gene

tic c

ode

to d

educ

e w

hich

cod

on(s

) cor

resp

onds

to

whi

ch a

min

o ac

id.

Uti

lizat

ion:

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Bi

olog

y To

pic

3.5

Gen

etic

mod

ifica

tion

and

biot

echn

olog

yTo

pic

7.2

Tran

scrip

tion

and

gene

exp

ress

ion

Topi

c 7.

3 Tr

ansl

atio

n

Aim

s:

• A

im 8

: The

re a

re e

thic

al im

plic

atio

ns in

alte

ring

the

geno

me

of a

n or

gani

sm

in o

rder

to p

rodu

ce p

rote

ins

for m

edic

al u

se in

hum

ans.


Biology guide 45

2.7

DN

A re

plic

atio

n, tr

ansc

ript

ion

and

tran

slat

ion

• Sk

ill: A

naly

sis

of M

esel

son

and

Stah

l’s re

sults

to o

btai

n su

ppor

t for

the

theo

ry

of s

emi-c

onse

rvat

ive

repl

icat

ion

of D

NA

.

• Sk

ill: U

se a

tabl

e of

mRN

A c

odon

s an

d th

eir c

orre

spon

ding

am

ino

acid

s to

ded

uce

the

sequ

ence

of a

min

o ac

ids

code

d by

a s

hort

mRN

A s

tran

d of

kn

own

base

seq

uenc

e.

• Sk

ill: D

educ

ing

the

DN

A b

ase

sequ

ence

for t

he m

RNA

str

and.

Gui

danc

e:

• Th

e di

ffer

ent t

ypes

of D

NA

pol

ymer

ase

do n

ot n

eed

to b

e di

stin

guis

hed.


Biology guide46

Esse

ntia

l ide

a: C

ell r

espi

ratio

n su

pplie

s en

ergy

for t

he fu

nctio

ns o

f life

.

2.8

Cell

resp

irat

ion

Nat

ure

of s

cien

ce:

Ass

essi

ng th

e et

hics

of s

cien

tific

rese

arch

—th

e us

e of

inve

rteb

rate

s in

resp

irom

eter

exp

erim

ents

has

eth

ical

impl

icat

ions

. (4.

5)

Und

erst

andi

ngs:

• Ce

ll re

spira

tion

is th

e co

ntro

lled

rele

ase

of e

nerg

y fr

om o

rgan

ic c

ompo

unds

to

pro

duce

ATP

.

• AT

P fr

om c

ell r

espi

ratio

n is

imm

edia

tely

ava

ilabl

e as

a s

ourc

e of

ene

rgy

in th

e ce

ll.

• A

naer

obic

cel

l res

pira

tion

give

s a

smal

l yie

ld o

f ATP

from

glu

cose

.

• A

erob

ic c

ell r

espi

ratio

n re

quire

s ox

ygen

and

giv

es a

larg

e yi

eld

of A

TP fr

om

gluc

ose.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: U

se o

f ana

erob

ic c

ell r

espi

ratio

n in

yea

sts

to p

rodu

ce e

than

ol

and

carb

on d

ioxi

de in

bak

ing.

• A

pplic

atio

n: L

acta

te p

rodu

ctio

n in

hum

ans

whe

n an

aero

bic

resp

iratio

n is

us

ed to

max

imiz

e th

e po

wer

of m

uscl

e co

ntra

ctio

ns.

• Sk

ill: A

naly

sis

of re

sults

from

exp

erim

ents

invo

lvin

g m

easu

rem

ent o

f re

spira

tion

rate

s in

ger

min

atin

g se

eds

or in

vert

ebra

tes

usin

g a

resp

irom

eter

.

Gui

danc

e:

• D

etai

ls o

f the

met

abol

ic p

athw

ays

of c

ell r

espi

ratio

n ar

e no

t nee

ded

but t

he

subs

trat

es a

nd fi

nal w

aste

pro

duct

s sh

ould

be

know

n.

• Th

ere

are

man

y si

mpl

e re

spiro

met

ers

whi

ch c

ould

be

used

. Stu

dent

s ar

e ex

pect

ed to

kno

w th

at a

n al

kali

is u

sed

to a

bsor

b CO

2, so

redu

ctio

ns in

vo

lum

e ar

e du

e to

oxy

gen

use.

Tem

pera

ture

sho

uld

be k

ept c

onst

ant t

o av

oid

volu

me

chan

ges

due

to te

mpe

ratu

re fl

uctu

atio

ns.

Aim

s:

• A

im 8

: The

eth

ics

of th

e us

e of

ani

mal

s in

exp

erim

ents

cou

ld b

e di

scus

sed

in re

latio

n to

resp

irom

eter

exp

erim

ents

. Lar

ge-s

cale

use

of f

ood

plan

ts fo

r bi

ofue

ls a

nd th

e re

sulti

ng im

pact

on

food

pric

es h

as e

thic

al im

plic

atio

ns.


Biology guide 47

Esse

ntia

l ide

a: P

hoto

synt

hesi

s us

es th

e en

ergy

in s

unlig

ht to

pro

duce

the

chem

ical

ene

rgy

need

ed fo

r life

.

2.9

Phot

osyn

thes

is

Nat

ure

of s

cien

ce:

Expe

rimen

tal d

esig

n—co

ntro

lling

rele

vant

var

iabl

es in

pho

tosy

nthe

sis

expe

rimen

ts is

ess

entia

l. (3

.1)

Und

erst

andi

ngs:

• Ph

otos

ynth

esis

is th

e pr

oduc

tion

of c

arbo

n co

mpo

unds

in c

ells

usi

ng li

ght

ener

gy.

• Vi

sibl

e lig

ht h

as a

rang

e of

wav

elen

gths

with

vio

let t

he s

hort

est w

avel

engt

h an

d re

d th

e lo

nges

t.

• Ch

loro

phyl

l abs

orbs

red

and

blue

ligh

t mos

t eff

ectiv

ely

and

refle

cts

gree

n lig

ht m

ore

than

oth

er c

olou

rs.

• O

xyge

n is

pro

duce

d in

pho

tosy

nthe

sis

from

the

phot

olys

is o

f wat

er.

• En

ergy

is n

eede

d to

pro

duce

car

bohy

drat

es a

nd o

ther

car

bon

com

poun

ds

from

car

bon

diox

ide.

• Te

mpe

ratu

re, l

ight

inte

nsity

and

car

bon

diox

ide

conc

entr

atio

n ar

e po

ssib

le

limiti

ng fa

ctor

s on

the

rate

of p

hoto

synt

hesi

s.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: C

hang

es to

the

Eart

h’s

atm

osph

ere,

oce

ans

and

rock

dep

ositi

on

due

to p

hoto

synt

hesi

s.

• Sk

ill: D

raw

ing

an a

bsor

ptio

n sp

ectr

um fo

r chl

orop

hyll

and

an a

ctio

n sp

ectr

um fo

r pho

tosy

nthe

sis.

• Sk

ill: D

esig

n of

exp

erim

ents

to in

vest

igat

e th

e ef

fect

of l

imiti

ng fa

ctor

s on

ph

otos

ynth

esis

.

• Sk

ill: S

epar

atio

n of

pho

tosy

nthe

tic p

igm

ents

by

chro

mat

ogra

ph. (

Prac

tical

4)

Uti

lizat

ion:

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Bi

olog

y To

pic

2.5

Enzy

mes


Biology guide48

2.9

Phot

osyn

thes

is

Gui

danc

e:

• St

uden

ts s

houl

d kn

ow th

at v

isib

le li

ght h

as w

avel

engt

hs b

etw

een

400

and

700

nano

met

res,

but

they

are

not

exp

ecte

d to

reca

ll th

e w

avel

engt

hs o

f sp

ecifi

c co

lour

s of

ligh

t.

• W

ater

free

of d

isso

lved

car

bon

diox

ide

for p

hoto

synt

hesi

s ex

perim

ents

can

be

pro

duce

d by

boi

ling

and

cool

ing

wat

er.

• Pa

per c

hrom

atog

raph

y ca

n be

use

d to

sep

arat

e ph

otos

ynth

etic

pig

men

ts b

ut

thin

laye

r chr

omat

ogra

phy

give

s be

tter

resu

lts.

49Biology guide 49

Core Topi

c 3:

Gen

etic

s 15

hou

rs

Esse

ntia

l ide

a: E

very

livi

ng o

rgan

ism

inhe

rits

a bl

uepr

int f

or li

fe fr

om it

s pa

rent

s.

3.1

Gen

es

Nat

ure

of s

cien

ce:

Dev

elop

men

ts in

sci

entif

ic re

sear

ch fo

llow

impr

ovem

ents

in te

chno

logy

—ge

ne s

eque

ncer

s ar

e us

ed fo

r the

seq

uenc

ing

of g

enes

. (1.

8)

Und

erst

andi

ngs:

• A

gen

e is

a h

erita

ble

fact

or th

at c

onsi

sts

of a

leng

th o

f DN

A a

nd in

fluen

ces

a sp

ecifi

c ch

arac

teris

tic.

• A

gen

e oc

cupi

es a

spe

cific

pos

ition

on

a ch

rom

osom

e.

• Th

e va

rious

spe

cific

form

s of

a g

ene

are

alle

les.

• A

llele

s di

ffer

from

eac

h ot

her b

y on

e or

onl

y a

few

bas

es.

• N

ew a

llele

s ar

e fo

rmed

by

mut

atio

n.

• Th

e ge

nom

e is

the

who

le o

f the

gen

etic

info

rmat

ion

of a

n or

gani

sm.

• Th

e en

tire

base

seq

uenc

e of

hum

an g

enes

was

seq

uenc

ed in

the

Hum

an

Gen

ome

Proj

ect.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: T

he c

ause

s of

sic

kle

cell

anem

ia, i

nclu

ding

a b

ase

subs

titut

ion

mut

atio

n, a

cha

nge

to th

e ba

se s

eque

nce

of m

RNA

tran

scrib

ed fr

om it

and

a

chan

ge to

the

sequ

ence

of a

pol

ypep

tide

in h

emog

lobi

n.

• A

pplic

atio

n: C

ompa

rison

of t

he n

umbe

r of g

enes

in h

uman

s w

ith o

ther

sp

ecie

s.

• Sk

ill: U

se o

f a d

atab

ase

to d

eter

min

e di

ffer

ence

s in

the

base

seq

uenc

e of

a

gene

in tw

o sp

ecie

s.

Inte

rnat

iona

l-m

inde

dnes

s:

• Se

quen

cing

of t

he h

uman

gen

ome

show

s th

at a

ll hu

man

s sh

are

the

vast

m

ajor

ity o

f the

ir ba

se s

eque

nces

but

als

o th

at th

ere

are

man

y si

ngle

nu

cleo

tide

poly

mor

phis

ms

that

con

trib

ute

to h

uman

div

ersi

ty.

Theo

ry o

f kno

wle

dge:

• Th

ere

is a

link

bet

wee

n si

ckle

cel

l ane

mia

and

pre

vale

nce

of m

alar

ia. H

ow c

an

we

know

whe

ther

ther

e is

a c

ausa

l lin

k in

suc

h ca

ses

or s

impl

y a

corr

elat

ion?

Aim

s:

• A

im 7

: The

use

of a

dat

abas

e to

com

pare

DN

A b

ase

sequ

ence

s.

• A

im 8

: Eth

ics

of p

aten

ting

hum

an g

enes

.

Topic 3: Genetics

Biology guide50

3.1

Gen

es

Gui

danc

e:

• St

uden

ts s

houl

d be

abl

e to

reca

ll on

e sp

ecifi

c ba

se s

ubst

itutio

n th

at c

ause

s gl

utam

ic a

cid

to b

e su

bstit

uted

by

valin

e as

the

sixt

h am

ino

acid

in th

e he

mog

lobi

n po

lype

ptid

e.

• Th

e nu

mbe

r of g

enes

in a

spe

cies

sho

uld

not b

e re

ferr

ed to

as

geno

me

size

as

this

term

is u

sed

for t

he to

tal a

mou

nt o

f DN

A. A

t lea

st o

ne p

lant

and

one

ba

cter

ium

sho

uld

be in

clud

ed in

the

com

paris

on a

nd a

t lea

st o

ne s

peci

es

with

mor

e ge

nes

and

one

with

few

er g

enes

than

a h

uman

.

• Th

e G

enba

nk®

data

base

can

be

used

to s

earc

h fo

r DN

A b

ase

sequ

ence

s. T

he

cyto

chro

me

C ge

ne s

eque

nce

is a

vaila

ble

for m

any

diff

eren

t org

anis

ms

and

is o

f par

ticul

ar in

tere

st b

ecau

se o

f its

use

in re

clas

sify

ing

orga

nism

s in

to th

ree

dom

ains

.

• D

elet

ions

, ins

ertio

ns a

nd fr

ame

shift

mut

atio

ns d

o no

t nee

d to

be

incl

uded

.

Topic 3: Genetics

Biology guide 51

Esse

ntia

l ide

a: C

hrom

osom

es c

arry

gen

es in

a li

near

seq

uenc

e th

at is

sha

red

by m

embe

rs o

f a s

peci

es.

3.2

Chro

mos

omes

Nat

ure

of s

cien

ce:

Dev

elop

men

ts in

rese

arch

follo

w im

prov

emen

ts in

tech

niqu

es—

auto

radi

ogra

phy

was

use

d to

est

ablis

h th

e le

ngth

of D

NA

mol

ecul

es in

chr

omos

omes

. (1.

8)

Und

erst

andi

ngs:

• Pr

okar

yote

s ha

ve o

ne c

hrom

osom

e co

nsis

ting

of a

circ

ular

DN

A m

olec

ule.

• So

me

prok

aryo

tes

also

hav

e pl

asm

ids

but e

ukar

yote

s do

not

.

• Eu

kary

ote

chro

mos

omes

are

line

ar D

NA

mol

ecul

es a

ssoc

iate

d w

ith h

isto

ne

prot

eins

.

• In

a e

ukar

yote

spe

cies

ther

e ar

e di

ffer

ent c

hrom

osom

es th

at c

arry

diff

eren

t ge

nes.

• H

omol

ogou

s ch

rom

osom

es c

arry

the

sam

e se

quen

ce o

f gen

es b

ut n

ot

nece

ssar

ily th

e sa

me

alle

les

of th

ose

gene

s.

• D

iplo

id n

ucle

i hav

e pa

irs o

f hom

olog

ous

chro

mos

omes

.

• H

aplo

id n

ucle

i hav

e on

e ch

rom

osom

e of

eac

h pa

ir.

• Th

e nu

mbe

r of c

hrom

osom

es is

a c

hara

cter

istic

feat

ure

of m

embe

rs o

f a

spec

ies.

• A

kar

yogr

am s

how

s th

e ch

rom

osom

es o

f an

orga

nism

in h

omol

ogou

s pa

irs o

f de

crea

sing

leng

th.

• Se

x is

det

erm

ined

by

sex

chro

mos

omes

and

aut

osom

es a

re c

hrom

osom

es

that

do

not d

eter

min

e se

x.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: C

airn

s’ te

chni

que

for m

easu

ring

the

leng

th o

f DN

A m

olec

ules

by

auto

radi

ogra

phy.

• A

pplic

atio

n: C

ompa

rison

of g

enom

e si

ze in

T2

phag

e, E

sche

richi

a co

li,

Dro

soph

ila m

elan

ogas

ter,

Hom

o sa

pien

s and

Par

is ja

poni

ca.

Inte

rnat

iona

l-m

inde

dnes

s:

• Se

quen

cing

of t

he ri

ce g

enom

e in

volv

ed c

oope

ratio

n be

twee

n bi

olog

ists

in

10 c

ount

ries.

Uti

lizat

ion:

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Bi

olog

y To

pic

1.6

Cell

divi

sion

Aim

s:

• A

im 6

: Sta

inin

g ro

ot ti

p sq

uash

es a

nd m

icro

scop

e ex

amin

atio

n of

ch

rom

osom

es is

reco

mm

ende

d bu

t not

obl

igat

ory.

• A

im 7

: Use

of d

atab

ases

to id

entif

y ge

ne lo

ci a

nd p

rote

in p

rodu

cts

of g

enes

.

Topic 3: Genetics

Biology guide52

3.2

Chro

mos

omes

• A

pplic

atio

n: C

ompa

rison

of d

iplo

id c

hrom

osom

e nu

mbe

rs o

f Hom

o sa

pien

s, Pa

n tr

oglo

dyte

s, Ca

nis f

amili

aris,

Ory

za sa

tiva,

Par

asca

ris e

quor

um.

• A

pplic

atio

n: U

se o

f kar

yogr

ams

to d

educ

e se

x an

d di

agno

se D

own

synd

rom

e in

hum

ans.

• Sk

ill: U

se o

f dat

abas

es to

iden

tify

the

locu

s of

a h

uman

gen

e an

d its

po

lype

ptid

e pr

oduc

t.

Gui

danc

e:

• Th

e te

rms

kary

otyp

e an

d ka

ryog

ram

hav

e di

ffer

ent m

eani

ngs.

Kar

yoty

pe is

a

prop

erty

of a

cel

l—th

e nu

mbe

r and

type

of c

hrom

osom

es p

rese

nt in

the

nucl

eus,

not

a p

hoto

grap

h or

dia

gram

of t

hem

.

• G

enom

e si

ze is

the

tota

l len

gth

of D

NA

in a

n or

gani

sm. T

he e

xam

ples

of

geno

me

and

chro

mos

ome

num

ber h

ave

been

sel

ecte

d to

allo

w p

oint

s of

in

tere

st to

be

rais

ed.

• Th

e tw

o D

NA

mol

ecul

es fo

rmed

by

DN

A re

plic

atio

n pr

ior t

o ce

ll di

visi

on a

re

cons

ider

ed to

be

sist

er c

hrom

atid

s un

til th

e sp

littin

g of

the

cent

rom

ere

at th

e st

art o

f ana

phas

e. A

fter

this

, the

y ar

e in

divi

dual

chr

omos

omes

.

Topic 3: Genetics

Biology guide 53

Esse

ntia

l ide

a: A

llele

s se

greg

ate

durin

g m

eios

is a

llow

ing

new

com

bina

tions

to b

e fo

rmed

by

the

fusi

on o

f gam

etes

.

3.3

Mei

osis

Nat

ure

of s

cien

ce:

Mak

ing

care

ful o

bser

vatio

ns—

mei

osis

was

dis

cove

red

by m

icro

scop

e ex

amin

atio

n of

div

idin

g ge

rm-li

ne c

ells

. (1.

8)

Und

erst

andi

ngs:

• O

ne d

iplo

id n

ucle

us d

ivid

es b

y m

eios

is to

pro

duce

four

hap

loid

nuc

lei.

• Th

e ha

lvin

g of

the

chro

mos

ome

num

ber a

llow

s a

sexu

al li

fe c

ycle

with

fusi

on

of g

amet

es.

• D

NA

is re

plic

ated

bef

ore

mei

osis

so

that

all

chro

mos

omes

con

sist

of t

wo

sist

er c

hrom

atid

s.

• Th

e ea

rly s

tage

s of

mei

osis

invo

lve

pairi

ng o

f hom

olog

ous

chro

mos

omes

and

cr

ossi

ng o

ver f

ollo

wed

by

cond

ensa

tion.

• O

rient

atio

n of

pai

rs o

f hom

olog

ous

chro

mos

omes

prio

r to

sepa

ratio

n is

ra

ndom

.

• Se

para

tion

of p

airs

of h

omol

ogou

s ch

rom

osom

es in

the

first

div

isio

n of

m

eios

is h

alve

s th

e ch

rom

osom

e nu

mbe

r.

• Cr

ossi

ng o

ver a

nd ra

ndom

orie

ntat

ion

prom

otes

gen

etic

var

iatio

n.

• Fu

sion

of g

amet

es fr

om d

iffer

ent p

aren

ts p

rom

otes

gen

etic

var

iatio

n.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: N

on-d

isju

nctio

n ca

n ca

use

Dow

n sy

ndro

me

and

othe

r ch

rom

osom

e ab

norm

aliti

es.

• A

pplic

atio

n: S

tudi

es s

how

ing

age

of p

aren

ts in

fluen

ces

chan

ces

of n

on-

disj

unct

ion.

Theo

ry o

f kno

wle

dge:

• In

192

2 th

e nu

mbe

r of c

hrom

osom

es c

ount

ed in

a h

uman

cel

l was

48.

Thi

s re

mai

ned

the

esta

blis

hed

num

ber f

or 3

0 ye

ars,

eve

n th

ough

a re

view

of

phot

ogra

phic

evi

denc

e fr

om th

e tim

e cl

early

sho

wed

that

ther

e w

ere

46. F

or

wha

t rea

sons

do

exis

ting

belie

fs c

arry

a c

erta

in in

ertia

?

Uti

lizat

ion:

• A

n un

ders

tand

ing

of k

aryo

type

s ha

s al

low

ed d

iagn

oses

to b

e m

ade

for t

he

purp

oses

of g

enet

ic c

ouns

ellin

g.

Sylla

bus

and

cros

s-cu

rric

ular

link

s: Bi

olog

y

Topi

c 1.

6 Ce

ll di

visi

on

Topi

c 10

.1 M

eios

is

Topi

c 11

.4 S

exua

l rep

rodu

ctio

n

Aim

s:

• A

im 8

: Pre

-nat

al s

cree

ning

for c

hrom

osom

e ab

norm

aliti

es g

ives

an

indi

catio

n of

the

sex

of th

e fe

tus

and

rais

es e

thic

al is

sues

ove

r sel

ectiv

e ab

ortio

n of

fe

mal

e fe

tuse

s in

som

e co

untr

ies.

Topic 3: Genetics

Biology guide54

3.3

Mei

osis

• A

pplic

atio

n: D

escr

iptio

n of

met

hods

use

d to

obt

ain

cells

for k

aryo

type

an

alys

is e

.g. c

horio

nic

villu

s sa

mpl

ing

and

amni

ocen

tesi

s an

d th

e as

soci

ated

ris

ks.

• Sk

ill: D

raw

ing

diag

ram

s to

sho

w th

e st

ages

of m

eios

is re

sulti

ng in

the

form

atio

n of

four

hap

loid

cel

ls.

Gui

danc

e:

• Pr

epar

atio

n of

mic

rosc

ope

slid

es s

how

ing

mei

osis

is c

halle

ngin

g an

d pe

rman

ent s

lides

sho

uld

be a

vaila

ble

in c

ase

no c

ells

in m

eios

is a

re v

isib

le in

te

mpo

rary

mou

nts.

• D

raw

ings

of t

he s

tage

s of

mei

osis

do

not n

eed

to in

clud

e ch

iasm

ata.

• Th

e pr

oces

s of

chi

asm

ata

form

atio

n ne

ed n

ot b

e ex

plai

ned.

Topic 3: Genetics

Biology guide 55

Esse

ntia

l ide

a: T

he in

herit

ance

of g

enes

follo

ws

patt

erns

.

3.4

Inhe

rita

nce

Nat

ure

of s

cien

ce:

Mak

ing

quan

titat

ive

mea

sure

men

ts w

ith re

plic

ates

to e

nsur

e re

liabi

lity.

Men

del’s

gen

etic

cro

sses

with

pea

pla

nts

gene

rate

d nu

mer

ical

dat

a. (3

.2)

Und

erst

andi

ngs:

• M

ende

l dis

cove

red

the

prin

cipl

es o

f inh

erita

nce

with

exp

erim

ents

in w

hich

la

rge

num

bers

of p

ea p

lant

s w

ere

cros

sed.

• G

amet

es a

re h

aplo

id s

o co

ntai

n on

ly o

ne a

llele

of e

ach

gene

.

• Th

e tw

o al

lele

s of

eac

h ge

ne s

epar

ate

into

diff

eren

t hap

loid

dau

ghte

r nuc

lei

durin

g m

eios

is.

• Fu

sion

of g

amet

es re

sults

in d

iplo

id z

ygot

es w

ith tw

o al

lele

s of

eac

h ge

ne

that

may

be

the

sam

e al

lele

or d

iffer

ent a

llele

s.

• D

omin

ant a

llele

s m

ask

the

effe

cts

of re

cess

ive

alle

les

but c

o-do

min

ant a

llele

s ha

ve jo

int e

ffec

ts.

• M

any

gene

tic d

isea

ses

in h

uman

s ar

e du

e to

rece

ssiv

e al

lele

s of

aut

osom

al

gene

s, a

lthou

gh s

ome

gene

tic d

isea

ses

are

due

to d

omin

ant o

r co-

dom

inan

t al

lele

s.

• So

me

gene

tic d

isea

ses

are

sex-

linke

d. T

he p

atte

rn o

f inh

erita

nce

is d

iffer

ent

with

sex

-link

ed g

enes

due

to th

eir l

ocat

ion

on s

ex c

hrom

osom

es.

• M

any

gene

tic d

isea

ses

have

bee

n id

entif

ied

in h

uman

s bu

t mos

t are

ver

y ra

re.

• Ra

diat

ion

and

mut

agen

ic c

hem

ical

s in

crea

se th

e m

utat

ion

rate

and

can

cau

se

gene

tic d

isea

ses

and

canc

er.

Theo

ry o

f kno

wle

dge:

• M

ende

l’s th

eorie

s w

ere

not a

ccep

ted

by th

e sc

ient

ific

com

mun

ity fo

r a lo

ng

time.

Wha

t fac

tors

wou

ld e

ncou

rage

the

acce

ptan

ce o

f new

idea

s by

the

scie

ntifi

c co

mm

unity

?

Uti

lizat

ion:

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Bi

olog

y To

pic

1.6

Cell

divi

sion

Aim

s:

• A

im 8

: Soc

ial i

mpl

icat

ions

of d

iagn

osis

of m

utat

ions

, inc

ludi

ng th

e ef

fect

s on

th

e fa

mily

and

stig

mat

izat

ion.

Topic 3: Genetics

Biology guide56

3.4

Inhe

rita

nce

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: In

herit

ance

of A

BO b

lood

gro

ups.

• A

pplic

atio

n: R

ed-g

reen

col

our b

lindn

ess

and

hem

ophi

lia a

s ex

ampl

es o

f sex

-lin

ked

inhe

ritan

ce.

• A

pplic

atio

n: In

herit

ance

of c

ystic

fibr

osis

and

Hun

tingt

on’s

dise

ase.

• A

pplic

atio

n: C

onse

quen

ces

of ra

diat

ion

afte

r nuc

lear

bom

bing

of H

irosh

ima

and

acci

dent

at C

hern

obyl

.

• Sk

ill: C

onst

ruct

ion

of P

unne

tt g

rids

for p

redi

ctin

g th

e ou

tcom

es o

f m

onoh

ybrid

gen

etic

cro

sses

.

• Sk

ill: C

ompa

rison

of p

redi

cted

and

act

ual o

utco

mes

of g

enet

ic c

ross

es u

sing

re

al d

ata.

• Sk

ill: A

naly

sis

of p

edig

ree

char

ts to

ded

uce

the

patt

ern

of in

herit

ance

of

gene

tic d

isea

ses.

Gui

danc

e:

• A

llele

s ca

rrie

d on

X c

hrom

osom

es s

houl

d be

sho

wn

as s

uper

scrip

t let

ters

on

an u

pper

cas

e X,

suc

h as

Xh .

• Th

e ex

pect

ed n

otat

ion

for A

BO b

lood

gro

up a

llele

s is

:

Phen

otyp

eO A B A

B

Gen

otyp

eii IA

IA o

r IAi

IB IB or I

B iIA

IB

Topic 3: Genetics

Biology guide 57

Esse

ntia

l ide

a: B

iolo

gist

s ha

ve d

evel

oped

tech

niqu

es fo

r art

ifici

al m

anip

ulat

ion

of D

NA

, cel

ls a

nd o

rgan

ism

s.

3.5

Gen

etic

mod

ific

atio

n an

d bi

otec

hnol

ogy

Nat

ure

of s

cien

ce:

Ass

essi

ng ri

sks

asso

ciat

ed w

ith s

cien

tific

rese

arch

—sc

ient

ists

att

empt

to a

sses

s th

e ris

ks a

ssoc

iate

d w

ith g

enet

ical

ly m

odifi

ed c

rops

or l

ives

tock

. (4.

8)

Und

erst

andi

ngs:

• G

el e

lect

roph

ores

is is

use

d to

sep

arat

e pr

otei

ns o

r fra

gmen

ts o

f DN

A

acco

rdin

g to

siz

e.

• PC

R ca

n be

use

d to

am

plify

sm

all a

mou

nts

of D

NA

.

• D

NA

pro

filin

g in

volv

es c

ompa

rison

of D

NA

.

• G

enet

ic m

odifi

catio

n is

car

ried

out b

y ge

ne tr

ansf

er b

etw

een

spec

ies.

• Cl

ones

are

gro

ups

of g

enet

ical

ly id

entic

al o

rgan

ism

s, d

eriv

ed fr

om a

sin

gle

orig

inal

par

ent c

ell.

• M

any

plan

t spe

cies

and

som

e an

imal

spe

cies

hav

e na

tura

l met

hods

of

clon

ing.

• A

nim

als

can

be c

lone

d at

the

embr

yo s

tage

by

brea

king

up

the

embr

yo in

to

mor

e th

an o

ne g

roup

of c

ells

.

• M

etho

ds h

ave

been

dev

elop

ed fo

r clo

ning

adu

lt an

imal

s us

ing

diff

eren

tiate

d ce

lls.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: U

se o

f DN

A p

rofil

ing

in p

ater

nity

and

fore

nsic

inve

stig

atio

ns.

• A

pplic

atio

n: G

ene

tran

sfer

to b

acte

ria u

sing

pla

smid

s m

akes

use

of r

estr

ictio

n en

donu

clea

ses

and

DN

A li

gase

.

• A

pplic

atio

n: A

sses

smen

t of t

he p

oten

tial r

isks

and

ben

efits

ass

ocia

ted

with

ge

netic

mod

ifica

tion

of c

rops

.

• A

pplic

atio

n: P

rodu

ctio

n of

clo

ned

embr

yos

prod

uced

by

som

atic

-cel

l nuc

lear

tr

ansf

er.

Theo

ry o

f kno

wle

dge:

• Th

e us

e of

DN

A fo

r sec

urin

g co

nvic

tions

in le

gal c

ases

is w

ell e

stab

lishe

d,

yet e

ven

univ

ersa

lly a

ccep

ted

theo

ries

are

over

turn

ed in

the

light

of n

ew

evid

ence

in s

cien

ce. W

hat c

riter

ia a

re n

eces

sary

for a

sses

sing

the

relia

bilit

y of

ev

iden

ce?

Uti

lizat

ion:

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Bi

olog

yTo

pic

2.7

DN

A re

plic

atio

n, tr

ansc

riptio

n an

d tr

ansl

atio

n

Aim

s:

• A

im 6

: The

des

ign

of a

root

ing

expe

rimen

t sho

uld

idea

lly le

ad to

the

expe

rimen

t act

ually

bei

ng c

arrie

d ou

t by

stud

ents

.

• A

im 8

: The

eth

ics

of g

enet

ic m

odifi

catio

n co

uld

be d

iscu

ssed

.

Topic 3: Genetics

Biology guide58

3.5

Gen

etic

mod

ific

atio

n an

d bi

otec

hnol

ogy

• Sk

ill: D

esig

n of

an

expe

rimen

t to

asse

ss o

ne fa

ctor

aff

ectin

g th

e ro

otin

g of

st

em-c

uttin

gs.

• Sk

ill: A

naly

sis

of e

xam

ples

of D

NA

pro

files

.

• Sk

ill: A

naly

sis

of d

ata

on ri

sks

to m

onar

ch b

utte

rflie

s of

Bt c

rops

.

Gui

danc

e:

• St

uden

ts s

houl

d be

abl

e to

ded

uce

whe

ther

or n

ot a

man

cou

ld b

e th

e fa

ther

of

a c

hild

from

the

patt

ern

of b

ands

on

a D

NA

pro

file.

• D

olly

can

be

used

as

an e

xam

ple

of s

omat

ic-c

ell t

rans

fer.

• A

pla

nt s

peci

es s

houl

d be

cho

sen

for r

ootin

g ex

perim

ents

that

form

s ro

ots

read

ily in

wat

er o

r a s

olid

med

ium

.

59Biology guide 59

Core Topi

c 4:

Eco

logy

12

hou

rs

Esse

ntia

l ide

a: T

he c

ontin

ued

surv

ival

of l

ivin

g or

gani

sms

incl

udin

g hu

man

s de

pend

s on

sus

tain

able

com

mun

ities

.

4.1

Spec

ies,

com

mun

itie

s an

d ec

osys

tem

s

Nat

ure

of s

cien

ce:

Look

ing

for p

atte

rns,

tren

ds a

nd d

iscr

epan

cies

—pl

ants

and

alg

ae a

re m

ostly

aut

otro

phic

but

som

e ar

e no

t. (3

.1)

Und

erst

andi

ngs:

• Sp

ecie

s ar

e gr

oups

of o

rgan

ism

s th

at c

an p

oten

tially

inte

rbre

ed to

pro

duce

fe

rtile

off

sprin

g.

• M

embe

rs o

f a sp

ecie

s may

be

repr

oduc

tivel

y is

olat

ed in

sepa

rate

pop

ulat

ions

.

• Sp

ecie

s ha

ve e

ither

an

auto

trop

hic

or h

eter

otro

phic

met

hod

of n

utrit

ion

(a

few

spe

cies

hav

e bo

th m

etho

ds).

• Co

nsum

ers

are

hete

rotr

ophs

that

feed

on

livin

g or

gani

sms

by in

gest

ion.

• D

etrit

ivor

es a

re h

eter

otro

phs

that

obt

ain

orga

nic

nut

rient

s fr

om d

etrit

us b

y in

tern

al d

iges

tion.

• Sa

prot

roph

s ar

e he

tero

trop

hs th

at o

btai

n or

gani

c n

utrie

nts

from

dea

d or

gani

sms

by e

xter

nal d

iges

tion.

• A

com

mun

ity is

form

ed b

y po

pula

tions

of d

iffer

ent s

peci

es li

ving

toge

ther

an

d in

tera

ctin

g w

ith e

ach

othe

r.

• A

com

mun

ity fo

rms

an e

cosy

stem

by

its in

tera

ctio

ns w

ith th

e ab

iotic

en

viro

nmen

t.

• Au

totr

ophs

obt

ain

inor

gani

c n

utrie

nts

from

the

abio

tic e

nviro

nmen

t.

• Th

e su

pply

of i

norg

anic

nut

rient

s is

mai

ntai

ned

by n

utrie

nt c

yclin

g.

• Ec

osys

tem

s ha

ve th

e po

tent

ial t

o be

sus

tain

able

ove

r lon

g pe

riods

of t

ime.

Inte

rnat

iona

l-m

inde

dnes

s:

• Th

e ne

ed fo

r sus

tain

abili

ty in

hum

an a

ctiv

ities

cou

ld b

e di

scus

sed

and

the

met

hods

nee

ded

to p

rom

ote

this

.

Uti

lizat

ion:

Sylla

bus

and

cros

s-cu

rric

ular

link

s:G

eogr

aphy

Part

2A

: Fre

sh w

ater

-issu

es a

nd c

onfli

cts

Envi

ronm

enta

l sys

tem

s an

d so

ciet

ies

Topi

c 2.

1 Sp

ecie

s an

d po

pula

tions

Aim

s:

• A

im 6

: It w

ould

be

best

for s

tude

nts

to o

btai

n da

ta fo

r the

chi

-squ

ared

test

th

emse

lves

, to

give

firs

t-ha

nd e

xper

ienc

e of

fiel

d w

ork

tech

niqu

es.

Topic 4: Ecology

Biology guide60

4.1

Spec

ies,

com

mun

itie

s an

d ec

osys

tem

s

App

licat

ions

and

ski

lls:

• Sk

ill: C

lass

ifyin

g sp

ecie

s as

aut

otro

phs,

con

sum

ers,

det

ritiv

ores

or s

apro

trop

hs

from

a k

now

ledg

e of

thei

r mod

e of

nut

ritio

n.

• Sk

ill: S

ettin

g up

seal

ed m

esoc

osm

s to

try

to e

stab

lish

sust

aina

bilit

y. (P

ract

ical

5)

• Sk

ill: T

estin

g fo

r ass

ocia

tion

betw

een

two

spec

ies

usin

g th

e ch

i-squ

ared

test

w

ith d

ata

obta

ined

by

quad

rat s

ampl

ing.

• Sk

ill: R

ecog

nizi

ng a

nd in

terp

retin

g st

atis

tical

sig

nific

ance

.

Gui

danc

e:

• M

esoc

osm

s ca

n be

set

up

in o

pen

tank

s, b

ut s

eale

d gl

ass

vess

els

are

pref

erab

le b

ecau

se e

ntry

and

exi

t of m

atte

r can

be

prev

ente

d bu

t lig

ht c

an

ente

r and

hea

t can

leav

e. A

quat

ic s

yste

ms

are

likel

y to

be

mor

e su

cces

sful

th

an te

rres

tria

l one

s.

• To

obt

ain

data

for t

he c

hi-s

quar

ed te

st, a

n ec

osys

tem

sho

uld

be c

hose

n in

w

hich

one

or m

ore

fact

ors

affe

ctin

g th

e di

strib

utio

n of

the

chos

en s

peci

es

varie

s. S

ampl

ing

shou

ld b

e ba

sed

on ra

ndom

num

bers

. In

each

qua

drat

the

pres

ence

or a

bsen

ce o

f the

cho

sen

spec

ies

shou

ld b

e re

cord

ed.

Topic 4: Ecology

Biology guide 61

Esse

ntia

l ide

a: E

cosy

stem

s re

quire

a c

ontin

uous

sup

ply

of e

nerg

y to

fuel

life

pro

cess

es a

nd to

repl

ace

ener

gy lo

st a

s he

at.

4.2

Ener

gy fl

ow

Nat

ure

of s

cien

ce:

Use

theo

ries

to e

xpla

in n

atur

al p

heno

men

a—th

e co

ncep

t of e

nerg

y flo

w e

xpla

ins

the

limite

d le

ngth

of f

ood

chai

ns. (

2.2)

Und

erst

andi

ngs:

• M

ost e

cosy

stem

s re

ly o

n a

supp

ly o

f ene

rgy

from

sun

light

.

• Li

ght e

nerg

y is

con

vert

ed to

che

mic

al e

nerg

y in

car

bon

com

poun

ds b

y ph

otos

ynth

esis

.

• Ch

emic

al e

nerg

y in

car

bon

com

poun

ds fl

ows

thro

ugh

food

cha

ins

by m

eans

of

feed

ing.

• En

ergy

rele

ased

from

car

bon

com

poun

ds b

y re

spira

tion

is u

sed

in li

ving

or

gani

sms

and

conv

erte

d to

hea

t.

• Li

ving

org

anis

ms

cann

ot c

onve

rt h

eat t

o ot

her f

orm

s of

ene

rgy.

• H

eat i

s lo

st fr

om e

cosy

stem

s.

• En

ergy

loss

es b

etw

een

trop

hic

leve

ls re

stric

t the

leng

th o

f foo

d ch

ains

and

th

e bi

omas

s of

hig

her t

roph

ic le

vels

.

App

licat

ions

and

ski

lls:

• Sk

ill: Q

uant

itativ

e re

pres

enta

tions

of e

nerg

y flo

w u

sing

pyr

amid

s of

ene

rgy.

Gui

danc

e:

• Py

ram

ids

of n

umbe

r and

bio

mas

s ar

e no

t req

uire

d. S

tude

nts

shou

ld b

e cl

ear

that

bio

mas

s in

terr

estr

ial e

cosy

stem

s di

min

ishe

s w

ith e

nerg

y al

ong

food

ch

ains

due

to lo

ss o

f car

bon

diox

ide,

wat

er a

nd o

ther

was

te p

rodu

cts,

suc

h as

ur

ea.

Inte

rnat

iona

l-m

inde

dnes

s:

• Th

e en

erge

tics

of fo

od c

hain

s is

a fa

ctor

in th

e ef

ficie

ncy

of fo

od p

rodu

ctio

n fo

r the

alle

viat

ion

of w

orld

hun

ger.

Uti

lizat

ion:

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Bi

olog

y To

pic

2.8

Cell

resp

iratio

nTo

pic

2.9

Phot

osyn

thes

isPh

ysic

sTo

pic

2.3

Wor

k, e

nerg

y an

d po

wer

Topi

c B.

2 Th

erm

odyn

amic

sEn

viro

nmen

tal s

yste

ms

and

soci

etie

sTo

pic

2.3

Flow

s of

ene

rgy

and

mat

ter

Topic 4: Ecology

Biology guide62

4.2

Ener

gy fl

ow

• Py

ram

ids

of e

nerg

y sh

ould

be

draw

n to

sca

le a

nd s

houl

d be

ste

pped

, not

tr

iang

ular

. The

term

s pr

oduc

er, f

irst c

onsu

mer

and

sec

ond

cons

umer

and

so

on s

houl

d be

use

d, ra

ther

than

firs

t tro

phic

leve

l, se

cond

trop

hic

leve

l and

so

on.

• Th

e di

stin

ctio

n be

twee

n en

ergy

flow

in e

cosy

stem

s an

d cy

clin

g of

inor

gani

c nu

trie

nts

shou

ld b

e st

ress

ed. S

tude

nts

shou

ld u

nder

stan

d th

at th

ere

is a

co

ntin

uous

but

var

iabl

e su

pply

of e

nerg

y in

the

form

of s

unlig

ht b

ut th

at th

e su

pply

of n

utrie

nts

in a

n ec

osys

tem

is fi

nite

and

lim

ited.

Topic 4: Ecology

Biology guide 63

Esse

ntia

l ide

a: C

ontin

ued

avai

labi

lity

of c

arbo

n in

eco

syst

ems

depe

nds

on c

arbo

n cy

clin

g.

4.3

Carb

on c

yclin

g

Nat

ure

of s

cien

ce:

Mak

ing

accu

rate

, qua

ntita

tive

mea

sure

men

ts—

it is

impo

rtan

t to

obta

in re

liabl

e da

ta o

n th

e co

ncen

trat

ion

of c

arbo

n di

oxid

e an

d m

etha

ne in

the

atm

osph

ere.

(3.1)

Und

erst

andi

ngs:

• Au

totr

ophs

con

vert

car

bon

diox

ide

into

car

bohy

drat

es a

nd o

ther

car

bon

com

poun

ds.

• In

aqu

atic

eco

syst

ems

carb

on is

pre

sent

as

diss

olve

d ca

rbon

dio

xide

and

hy

drog

enca

rbon

ate

ions

.

• Ca

rbon

dio

xide

diff

uses

from

the

atm

osph

ere

or w

ater

into

aut

otro

phs.

• Ca

rbon

dio

xide

is p

rodu

ced

by re

spira

tion

and

diff

uses

out

of o

rgan

ism

s in

to

wat

er o

r the

atm

osph

ere.

• M

etha

ne is

pro

duce

d fr

om o

rgan

ic m

atte

r in

anae

robi

c co

nditi

ons

by

met

hano

geni

c ar

chae

ans

and

som

e di

ffus

es in

to th

e at

mos

pher

e or

ac

cum

ulat

es in

the

grou

nd.

• M

etha

ne is

oxi

dize

d to

car

bon

diox

ide

and

wat

er in

the

atm

osph

ere.

• Pe

at fo

rms

whe

n or

gani

c m

atte

r is

not f

ully

dec

ompo

sed

beca

use

of a

cidi

c an

d/or

ana

erob

ic c

ondi

tions

in w

ater

logg

ed s

oils

.

• Pa

rtia

lly d

ecom

pose

d or

gani

c m

atte

r fro

m p

ast g

eolo

gica

l era

s w

as

conv

erte

d ei

ther

into

coa

l or i

nto

oil a

nd g

as th

at a

ccum

ulat

e in

por

ous

rock

s.

• Ca

rbon

dio

xide

is p

rodu

ced

by th

e co

mbu

stio

n of

bio

mas

s an

d fo

ssili

zed

orga

nic

mat

ter.

• A

nim

als

such

as

reef

-bui

ldin

g co

rals

and

mol

lusc

a ha

ve h

ard

part

s th

at a

re

com

pose

d of

cal

cium

car

bona

te a

nd c

an b

ecom

e fo

ssili

zed

in li

mes

tone

.

Uti

lizat

ion:

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Ph

ysic

sTo

pic

8.1

Ener

gy s

ourc

esCh

emis

try

Topi

c C

.2 F

ossi

l fue

lsTo

pic

C.5

Env

ironm

enta

l im

pact

—gl

obal

war

min

g

Aim

s:

• A

im 8

: The

eth

ical

impl

icat

ions

of d

iver

ting

crop

s su

ch a

s m

aize

from

a fo

od

to a

fuel

cro

p co

uld

be c

onsi

dere

d.

Topic 4: Ecology

Biology guide64

4.3

Carb

on c

yclin

g

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: E

stim

atio

n of

car

bon

fluxe

s du

e to

pro

cess

es in

the

carb

on c

ycle

.

• A

pplic

atio

n: A

naly

sis

of d

ata

from

air

mon

itorin

g st

atio

ns to

exp

lain

ann

ual

fluct

uatio

ns.

• Sk

ill: C

onst

ruct

a d

iagr

am o

f the

car

bon

cycl

e.

Gui

danc

e:

• Ca

rbon

flux

es s

houl

d be

mea

sure

d in

gig

aton

nes.

Topic 4: Ecology

Biology guide 65

Esse

ntia

l ide

a: C

once

ntra

tions

of g

ases

in th

e at

mos

pher

e af

fect

clim

ates

exp

erie

nced

at t

he E

arth

’s su

rfac

e.

4.4

Clim

ate

chan

ge

Nat

ure

of s

cien

ce:

Ass

essi

ng c

laim

s—as

sess

men

t of t

he c

laim

s th

at h

uman

act

iviti

es a

re p

rodu

cing

clim

ate

chan

ge. (

5.2)

Und

erst

andi

ngs:

• Ca

rbon

dio

xide

and

wat

er v

apou

r are

the

mos

t sig

nific

ant g

reen

hous

e ga

ses.

• O

ther

gas

es in

clud

ing

met

hane

and

nitr

ogen

oxi

des

have

less

impa

ct.

• Th

e im

pact

of a

gas

dep

ends

on

its a

bilit

y to

abs

orb

long

wav

e ra

diat

ion

as

wel

l as

on it

s co

ncen

trat

ion

in th

e at

mos

pher

e.

• Th

e w

arm

ed E

arth

em

its lo

nger

wav

elen

gth

radi

atio

n (h

eat).

• Lo

nger

wav

e ra

diat

ion

is a

bsor

bed

by g

reen

hous

e ga

ses

that

reta

in th

e he

at

in th

e at

mos

pher

e.

• G

loba

l tem

pera

ture

s an

d cl

imat

e pa

tter

ns a

re in

fluen

ced

by c

once

ntra

tions

of

gre

enho

use

gase

s.

• Th

ere

is a

cor

rela

tion

betw

een

risin

g at

mos

pher

ic c

once

ntra

tions

of c

arbo

n di

oxid

e si

nce

the

star

t of t

he in

dust

rial r

evol

utio

n 20

0 ye

ars

ago

and

aver

age

glob

al te

mpe

ratu

res.

• Re

cent

incr

ease

s in

atm

osph

eric

car

bon

diox

ide

are

larg

ely

due

to in

crea

ses

in th

e co

mbu

stio

n of

foss

ilize

d or

gani

c m

atte

r.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: T

hrea

ts to

cor

al re

efs

from

incr

easi

ng c

once

ntra

tions

of d

isso

lved

ca

rbon

dio

xide

.

• A

pplic

atio

n: C

orre

latio

ns b

etw

een

glob

al te

mpe

ratu

res

and

carb

on d

ioxi

de

conc

entr

atio

ns o

n Ea

rth.

• A

pplic

atio

n: E

valu

atin

g cl

aim

s th

at h

uman

act

iviti

es a

re n

ot c

ausi

ng c

limat

e ch

ange

.

Inte

rnat

iona

l-m

inde

dnes

s:

• Re

leas

e of

gre

enho

use

gase

s oc

curs

loca

lly b

ut h

as a

glo

bal i

mpa

ct, s

o in

tern

atio

nal c

oope

ratio

n to

redu

ce e

mis

sion

s is

ess

entia

l.

Theo

ry o

f kno

wle

dge:

• Th

e pr

ecau

tiona

ry p

rinci

ple

is m

eant

to g

uide

dec

isio

n-m

akin

g in

con

ditio

ns

whe

re a

lack

of c

erta

inty

exi

sts.

Is c

erta

inty

eve

r pos

sibl

e in

the

natu

ral

scie

nces

?

Uti

lizat

ion:

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Ph

ysic

sTo

pic

8.2

Ther

mal

ene

rgy

tran

sfer

Geo

grap

hyPa

rt 1

.3 P

atte

rns

in e

nviro

nmen

tal q

ualit

y an

d su

stai

nabi

lity/

Atm

osph

ere

and

chan

geEn

viro

nmen

tal s

yste

ms

and

soci

etie

sTo

pic

7.2

Clim

ate

chan

ge—

caus

es a

nd im

pact

s

Aim

s:

• A

im 7

: Dat

abas

es c

an b

e us

ed to

ana

lyse

con

cent

ratio

ns o

f gre

enho

use

gase

s.

• A

im 8

: The

re a

re in

tere

stin

g pa

ralle

ls b

etw

een

hum

ans

that

are

unw

illin

g to

re

duce

thei

r car

bon

foot

prin

t and

che

atin

g in

soc

ial a

nim

als.

Whe

n th

e le

vel

of c

heat

ing

rises

abo

ve a

cer

tain

leve

l, so

cial

beh

avio

ur b

reak

s do

wn.

Topic 4: Ecology

Biology guide66

4.4

Clim

ate

chan

ge

Gui

danc

e:

• Ca

rbon

dio

xide

, met

hane

and

wat

er v

apou

r sho

uld

be in

clud

ed in

di

scus

sion

s.

• Th

e ha

rmfu

l con

sequ

ence

s of

ozo

ne d

eple

tion

do n

ot n

eed

to b

e di

scus

sed

and

it sh

ould

be

mad

e cl

ear t

hat o

zone

dep

letio

n is

not

the

caus

e of

the

enha

nced

gre

enho

use

effe

ct.

67Biology guide 67

Core Topi

c 5:

Evo

lutio

n an

d bi

odiv

ersi

ty

12 h

ours

Esse

ntia

l ide

a: T

here

is o

verw

helm

ing

evid

ence

for t

he e

volu

tion

of li

fe o

n Ea

rth.

5.1

Evi

denc

e fo

r evo

luti

on

Nat

ure

of s

cien

ce:

Look

ing

for p

atte

rns,

tren

ds a

nd d

iscr

epan

cies

—th

ere

are

com

mon

feat

ures

in th

e bo

ne s

truc

ture

of v

erte

brat

e lim

bs d

espi

te th

eir v

arie

d us

e. (3

.1)

Und

erst

andi

ngs:

• Ev

olut

ion

occu

rs w

hen

herit

able

cha

ract

eris

tics

of a

spe

cies

cha

nge.

• Th

e fo

ssil

reco

rd p

rovi

des

evid

ence

for e

volu

tion.

• Se

lect

ive

bree

ding

of d

omes

ticat

ed a

nim

als

show

s th

at a

rtifi

cial

sel

ectio

n ca

n ca

use

evol

utio

n.

• Ev

olut

ion

of h

omol

ogou

s st

ruct

ures

by

adap

tive

radi

atio

n ex

plai

ns

sim

ilarit

ies

in s

truc

ture

whe

n th

ere

are

diff

eren

ces

in fu

nctio

n.

• Po

pula

tions

of a

spe

cies

can

gra

dual

ly d

iver

ge in

to s

epar

ate

spec

ies

by

evol

utio

n.

• Co

ntin

uous

var

iatio

n ac

ross

the

geog

raph

ical

rang

e of

rela

ted

popu

latio

ns

mat

ches

the

conc

ept o

f gra

dual

div

erge

nce.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: D

evel

opm

ent o

f mel

anis

tic in

sect

s in

pol

lute

d ar

eas.

• A

pplic

atio

n: C

ompa

rison

of t

he p

enta

dact

yl li

mb

of m

amm

als,

bird

s,

amph

ibia

ns a

nd re

ptile

s w

ith d

iffer

ent m

etho

ds o

f loc

omot

ion.

Theo

ry o

f kno

wle

dge:

• Ev

olut

iona

ry h

isto

ry is

an

espe

cial

ly c

halle

ngin

g ar

ea o

f sci

ence

bec

ause

ex

perim

ents

can

not b

e pe

rfor

med

to e

stab

lish

past

eve

nts

or th

eir c

ause

s.

Ther

e ar

e no

neth

eles

s sc

ient

ific

met

hods

of e

stab

lishi

ng b

eyon

d re

ason

able

do

ubt w

hat h

appe

ned

in s

ome

case

s. H

ow d

o th

ese

met

hods

com

pare

to

thos

e us

ed b

y hi

stor

ians

to re

cons

truc

t the

pas

t?

Uti

lizat

ion:

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Ph

ysic

sTo

pic

7.1 D

iscr

ete

ener

gy a

nd ra

dioa

ctiv

ityG

eogr

aphy

Pa

rt 1

.3 P

atte

rns

in e

nviro

nmen

tal q

ualit

y an

d su

stai

nabi

lity/

Biod

iver

sity

and

ch

ange

Envi

ronm

enta

l sys

tem

s an

d so

ciet

ies

Topi

c 4

Biod

iver

sity

in e

cosy

stem

s

Topic 5: Evolution and biodiversity

Biology guide68

Esse

ntia

l ide

a: T

he d

iver

sity

of l

ife h

as e

volv

ed a

nd c

ontin

ues

to e

volv

e by

nat

ural

sel

ectio

n.

5.2

Nat

ural

sel

ecti

on

Nat

ure

of s

cien

ce:

Use

theo

ries

to e

xpla

in n

atur

al p

heno

men

a—th

e th

eory

of e

volu

tion

by n

atur

al s

elec

tion

can

expl

ain

the

deve

lopm

ent o

f ant

ibio

tic re

sist

ance

in b

acte

ria. (

2.1)

Und

erst

andi

ngs:

• N

atur

al s

elec

tion

can

only

occ

ur if

ther

e is

var

iatio

n am

ong

mem

bers

of t

he

sam

e sp

ecie

s.

• M

utat

ion,

mei

osis

and

sex

ual r

epro

duct

ion

caus

e va

riatio

n be

twee

n in

divi

dual

s in

a s

peci

es.

• A

dapt

atio

ns a

re c

hara

cter

istic

s th

at m

ake

an in

divi

dual

sui

ted

to it

s en

viro

nmen

t and

way

of l

ife.

• Sp

ecie

s te

nd to

pro

duce

mor

e of

fspr

ing

than

the

envi

ronm

ent c

an s

uppo

rt.

• In

divi

dual

s th

at a

re b

ette

r ada

pted

tend

to s

urvi

ve a

nd p

rodu

ce m

ore

offs

prin

g w

hile

the

less

wel

l ada

pted

tend

to d

ie o

r pro

duce

few

er o

ffsp

ring.

• In

divi

dual

s th

at re

prod

uce

pass

on

char

acte

ristic

s to

thei

r off

sprin

g.

• N

atur

al s

elec

tion

incr

ease

s th

e fr

eque

ncy

of c

hara

cter

istic

s th

at m

ake

indi

vidu

als

bett

er a

dapt

ed a

nd d

ecre

ases

the

freq

uenc

y of

oth

er

char

acte

ristic

s le

adin

g to

cha

nges

with

in th

e sp

ecie

s.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: C

hang

es in

bea

ks o

f fin

ches

on

Dap

hne

Maj

or.

• A

pplic

atio

n: E

volu

tion

of a

ntib

iotic

resi

stan

ce in

bac

teria

.

Gui

danc

e:

• St

uden

ts s

houl

d be

cle

ar th

at c

hara

cter

istic

s ac

quire

d du

ring

the

lifet

ime

of

an in

divi

dual

are

not

her

itabl

e. T

he te

rm L

amar

ckis

m is

not

requ

ired.

Theo

ry o

f kno

wle

dge:

• N

atur

al S

elec

tion

is a

theo

ry. H

ow m

uch

evid

ence

is re

quire

d to

sup

port

a

theo

ry a

nd w

hat s

ort o

f cou

nter

evi

denc

e is

requ

ired

to re

fute

it?


Biology guide 69

Esse

ntia

l ide

a: S

peci

es a

re n

amed

and

cla

ssifi

ed u

sing

an

inte

rnat

iona

lly a

gree

d sy

stem

.

5.3

Clas

sifi

cati

on o

f bio

dive

rsit

y

Nat

ure

of s

cien

ce:

Coop

erat

ion

and

colla

bora

tion

betw

een

grou

ps o

f sci

entis

ts—

scie

ntis

ts u

se th

e bi

nom

ial s

yste

m to

iden

tify

a sp

ecie

s ra

ther

than

the

man

y di

ffer

ent l

ocal

nam

es. (

4.3)

Und

erst

andi

ngs:

• Th

e bi

nom

ial s

yste

m o

f nam

es fo

r spe

cies

is u

nive

rsal

am

ong

biol

ogis

ts a

nd

has

been

agr

eed

and

deve

lope

d at

a s

erie

s of

con

gres

ses.

• W

hen

spec

ies

are

disc

over

ed th

ey a

re g

iven

sci

entif

ic n

ames

usi

ng th

e bi

nom

ial s

yste

m.

• Ta

xono

mis

ts c

lass

ify s

peci

es u

sing

a h

iera

rchy

of t

axa.

• A

ll or

gani

sms

are

clas

sifie

d in

to th

ree

dom

ains

.

• Th

e pr

inci

pal t

axa

for c

lass

ifyin

g eu

kary

otes

are

kin

gdom

, phy

lum

, cla

ss,

orde

r, fa

mily

, gen

us a

nd s

peci

es.

• In

a n

atur

al c

lass

ifica

tion,

the

genu

s an

d ac

com

pany

ing

high

er ta

xa c

onsi

st o

f al

l the

spe

cies

that

hav

e ev

olve

d fr

om o

ne c

omm

on a

nces

tral

spe

cies

.

• Ta

xono

mis

ts s

omet

imes

recl

assi

fy g

roup

s of

spe

cies

whe

n ne

w e

vide

nce

show

s th

at a

pre

viou

s ta

xon

cont

ains

spe

cies

that

hav

e ev

olve

d fr

om

diff

eren

t anc

estr

al s

peci

es.

• N

atur

al c

lass

ifica

tions

hel

p in

iden

tific

atio

n of

spe

cies

and

allo

w th

e pr

edic

tion

of c

hara

cter

istic

s sh

ared

by

spec

ies

with

in a

gro

up.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: C

lass

ifica

tion

of o

ne p

lant

and

one

ani

mal

spe

cies

from

dom

ain

to s

peci

es le

vel.

• A

pplic

atio

n: R

ecog

nitio

n fe

atur

es o

f bry

ophy

ta, f

ilici

noph

yta,

con

ifero

phyt

a an

d an

gios

perm

ophy

ta.

Inte

rnat

iona

l-m

inde

dnes

s:

• Th

ere

are

inte

rnat

iona

l cod

es o

f nom

encl

atur

e an

d ag

reem

ents

as

to th

e pr

inci

ples

to b

e fo

llow

ed in

the

clas

sific

atio

n of

livi

ng o

rgan

ism

s.

Theo

ry o

f kno

wle

dge:

• Th

e ad

optio

n of

a s

yste

m o

f bin

omia

l nom

encl

atur

e is

larg

ely

due

to S

wed

ish

bota

nist

and

phy

sici

an C

arol

us L

inna

eus

(170

7–17

78).

Linn

aeus

als

o de

fined

fo

ur g

roup

s of

hum

ans,

and

the

divi

sion

s w

ere

base

d on

bot

h ph

ysic

al a

nd

soci

al tr

aits

. By

21st

-cen

tury

sta

ndar

ds, h

is d

escr

iptio

ns c

an b

e re

gard

ed a

s ra

cist

. How

doe

s th

e so

cial

con

text

of s

cien

tific

wor

k af

fect

the

met

hods

an

d fin

ding

s of

rese

arch

? Is

it n

eces

sary

to c

onsi

der t

he s

ocia

l con

text

whe

n ev

alua

ting

ethi

cal a

spec

ts o

f kno

wle

dge

clai

ms?


Biology guide70

5.3

Clas

sifi

cati

on o

f bio

dive

rsit

y

• A

pplic

atio

n: R

ecog

nitio

n fe

atur

es o

f por

ifera

, cni

daria

, pla

tyhe

lmin

tha,

an

nelid

a, m

ollu

sca,

art

hrop

oda

and

chor

data

.

• A

pplic

atio

n: R

ecog

nitio

n of

feat

ures

of b

irds,

mam

mal

s, a

mph

ibia

ns, r

eptil

es

and

fish.

• Sk

ill: C

onst

ruct

ion

of d

icho

tom

ous

keys

for u

se in

iden

tifyi

ng s

peci

men

s.

Gui

danc

e:

• A

rcha

ea, e

ubac

teria

and

euk

aryo

te s

houl

d be

use

d fo

r the

thre

e do

mai

ns.

• M

embe

rs o

f the

se d

omai

ns s

houl

d be

refe

rred

to a

s ar

chae

ans,

bac

teria

and

eu

kary

otes

.

• St

uden

ts s

houl

d kn

ow w

hich

pla

nt p

hyla

hav

e va

scul

ar ti

ssue

, but

oth

er

inte

rnal

det

ails

are

not

requ

ired.

• Re

cogn

ition

feat

ures

exp

ecte

d fo

r the

sel

ecte

d an

imal

phy

la a

re th

ose

that

are

mos

t use

ful i

n di

stin

guis

hing

the

grou

ps fr

om e

ach

othe

r and

full

desc

riptio

ns o

f the

cha

ract

eris

tics

of e

ach

phyl

um a

re n

ot n

eede

d.

• Vi

ruse

s ar

e no

t cla

ssifi

ed a

s liv

ing

orga

nism

s.


Biology guide 71

Esse

ntia

l ide

a: T

he a

nces

try

of g

roup

s of

spe

cies

can

be

dedu

ced

by c

ompa

ring

thei

r bas

e or

am

ino

acid

seq

uenc

es.

5.4

Clad

isti

cs

Nat

ure

of s

cien

ce:

Fals

ifica

tion

of th

eorie

s w

ith o

ne th

eory

bei

ng s

uper

sede

d by

ano

ther

—pl

ant f

amili

es h

ave

been

recl

assi

fied

as a

resu

lt of

evi

denc

e fr

om c

ladi

stic

s. (1

.9)

Und

erst

andi

ngs:

• A

cla

de is

a g

roup

of o

rgan

ism

s th

at h

ave

evol

ved

from

a c

omm

on a

nces

tor.

• Ev

iden

ce fo

r whi

ch s

peci

es a

re p

art o

f a c

lade

can

be

obta

ined

from

the

base

se

quen

ces

of a

gen

e or

the

corr

espo

ndin

g am

ino

acid

seq

uenc

e of

a p

rote

in.

• Se

quen

ce d

iffer

ence

s ac

cum

ulat

e gr

adua

lly s

o th

ere

is a

pos

itive

cor

rela

tion

betw

een

the

num

ber o

f diff

eren

ces

betw

een

two

spec

ies

and

the

time

sinc

e th

ey d

iver

ged

from

a c

omm

on a

nces

tor.

• Tr

aits

can

be

anal

ogou

s or

hom

olog

ous.

• Cl

adog

ram

s ar

e tr

ee d

iagr

ams

that

sho

w th

e m

ost p

roba

ble

sequ

ence

of

dive

rgen

ce in

cla

des.

• Ev

iden

ce fr

om c

ladi

stic

s ha

s sh

own

that

cla

ssifi

catio

ns o

f som

e gr

oups

bas

ed

on s

truc

ture

did

not

cor

resp

ond

with

the

evol

utio

nary

orig

ins

of a

gro

up o

r sp

ecie

s.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: C

lado

gram

s in

clud

ing

hum

ans

and

othe

r prim

ates

.

• A

pplic

atio

n: R

ecla

ssifi

catio

n of

the

figw

ort f

amily

usi

ng e

vide

nce

from

cl

adis

tics.

• Sk

ill: A

naly

sis

of c

lado

gram

s to

ded

uce

evol

utio

nary

rela

tions

hips

.

Theo

ry o

f kno

wle

dge:

• A

maj

or s

tep

forw

ard

in th

e st

udy

of b

acte

ria w

as th

e re

cogn

ition

in 1

977

by

Carl

Woe

se th

at A

rcha

ea h

ave

a se

para

te li

ne o

f evo

lutio

nary

des

cent

from

ba

cter

ia. F

amou

s sc

ient

ists

, inc

ludi

ng L

uria

and

May

r, ob

ject

ed to

his

div

isio

n of

the

prok

aryo

tes.

To

wha

t ext

ent i

s co

nser

vatis

m in

sci

ence

des

irabl

e?

Biology guide72

Core Topi

c 6:

Hum

an p

hysi

olog

y 20

hou

rs

Esse

ntia

l ide

a: T

he s

truc

ture

of t

he w

all o

f the

sm

all i

ntes

tine

allo

ws

it to

mov

e, d

iges

t and

abs

orb

food

.

6.1

Dig

esti

on a

nd a

bsor

ptio

n

Nat

ure

of s

cien

ce:

Use

mod

els

as re

pres

enta

tions

of t

he re

al w

orld

—di

alys

is tu

bing

can

be

used

to m

odel

abs

orpt

ion

in th

e in

test

ine.

(1.1

0)

Und

erst

andi

ngs:

• Th

e co

ntra

ctio

n of

circ

ular

and

long

itudi

nal m

uscl

e of

the

smal

l int

estin

e m

ixes

the

food

with

enz

ymes

and

mov

es it

alo

ng th

e gu

t.

• Th

e pa

ncre

as s

ecre

tes

enzy

mes

into

the

lum

en o

f the

sm

all i

ntes

tine.

• En

zym

es d

iges

t mos

t mac

rom

olec

ules

in fo

od in

to m

onom

ers

in th

e sm

all

inte

stin

e.

• Vi

lli in

crea

se th

e su

rfac

e ar

ea o

f epi

thel

ium

ove

r whi

ch a

bsor

ptio

n is

car

ried

out.

• Vi

lli a

bsor

b m

onom

ers

form

ed b

y di

gest

ion

as w

ell a

s m

iner

al io

ns a

nd

vita

min

s.

• D

iffer

ent m

etho

ds o

f mem

bran

e tr

ansp

ort a

re re

quire

d to

abs

orb

diff

eren

t nu

trie

nts.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: P

roce

sses

occ

urrin

g in

the

smal

l int

estin

e th

at re

sult

in th

e di

gest

ion

of s

tarc

h an

d tr

ansp

ort o

f the

pro

duct

s of

dig

estio

n to

the

liver

.

• A

pplic

atio

n: U

se o

f dia

lysi

s tu

bing

to m

odel

abs

orpt

ion

of d

iges

ted

food

in

the

inte

stin

e.

Uti

lizat

ion:

• So

me

hydr

olyt

ic e

nzym

es h

ave

econ

omic

impo

rtan

ce, f

or e

xam

ple

amyl

ase

in p

rodu

ctio

n of

sug

ars

from

sta

rch

and

in th

e br

ewin

g of

bee

r.

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Bi

olog

y To

pic

2.1

Mol

ecul

es to

met

abol

ism

Topi

c 2.

5 En

zym

es

Topic 6: Human physiology

Biology guide 73

6.1

Dig

esti

on a

nd a

bsor

ptio

n

• Sk

ill: P

rodu

ctio

n of

an

anno

tate

d di

agra

m o

f the

dig

estiv

e sy

stem

.

• Sk

ill: I

dent

ifica

tion

of ti

ssue

laye

rs in

tran

sver

se s

ectio

ns o

f the

sm

all i

ntes

tine

view

ed w

ith a

mic

rosc

ope

or in

a m

icro

grap

h.

Gui

danc

e:

• St

uden

ts s

houl

d kn

ow th

at a

myl

ase,

lipa

se a

nd a

n en

dope

ptid

ase

are

secr

eted

by

the

panc

reas

. The

nam

e tr

ypsi

n an

d th

e m

etho

d us

ed to

act

ivat

e it

are

not r

equi

red.

• St

uden

ts s

houl

d kn

ow th

at s

tarc

h, g

lyco

gen,

lipi

ds a

nd n

ucle

ic a

cids

are

di

gest

ed in

to m

onom

ers

and

that

cel

lulo

se re

mai

ns u

ndig

este

d.

• Ti

ssue

laye

rs s

houl

d in

clud

e lo

ngitu

dina

l and

circ

ular

mus

cles

, muc

osa

and

epith

eliu

m.


Biology guide74

Ess

enti

al id

ea: T

he b

lood

sys

tem

con

tinuo

usly

tran

spor

ts s

ubst

ance

s to

cel

ls a

nd s

imul

tane

ousl

y co

llect

s w

aste

pro

duct

s.

6.2

The

bloo

d sy

stem

Nat

ure

of s

cien

ce:

Theo

ries

are

rega

rded

as

unce

rtai

n—W

illia

m H

arve

y ov

ertu

rned

theo

ries

deve

lope

d by

the

anci

ent G

reek

phi

loso

pher

Gal

en o

n m

ovem

ent o

f blo

od in

the

body

. (1.

9)

Und

erst

andi

ngs:

• A

rter

ies

conv

ey b

lood

at h

igh

pres

sure

from

the

vent

ricle

s to

the

tissu

es o

f th

e bo

dy.

• A

rter

ies

have

mus

cle

cells

and

ela

stic

fibr

es in

thei

r wal

ls.

• Th

e m

uscl

e an

d el

astic

fibr

es a

ssis

t in

mai

ntai

ning

blo

od p

ress

ure

betw

een

pum

p cy

cles

.

• Bl

ood

flow

s th

roug

h tis

sues

in c

apill

arie

s. C

apill

arie

s ha

ve p

erm

eabl

e w

alls

th

at a

llow

exc

hang

e of

mat

eria

ls b

etw

een

cells

in th

e tis

sue

and

the

bloo

d in

th

e ca

pilla

ry.

• Ve

ins

colle

ct b

lood

at l

ow p

ress

ure

from

the

tissu

es o

f the

bod

y an

d re

turn

it

to th

e at

ria o

f the

hea

rt.

• Va

lves

in v

eins

and

the

hear

t ens

ure

circ

ulat

ion

of b

lood

by

prev

entin

g ba

ckflo

w.

• Th

ere

is a

sep

arat

e ci

rcul

atio

n fo

r the

lung

s.

• Th

e he

art b

eat i

s in

itiat

ed b

y a

grou

p of

spe

cial

ized

mus

cle

cells

in th

e rig

ht

atriu

m c

alle

d th

e si

noat

rial n

ode.

• Th

e si

noat

rial n

ode

acts

as

a pa

cem

aker

.

• Th

e si

noat

rial n

ode

send

s ou

t an

elec

tric

al s

igna

l tha

t stim

ulat

es c

ontr

actio

n as

it is

pro

paga

ted

thro

ugh

the

wal

ls o

f the

atr

ia a

nd th

en th

e w

alls

of t

he

vent

ricle

s.

• Th

e he

art r

ate

can

be in

crea

sed

or d

ecre

ased

by

impu

lses

bro

ught

to th

e he

art t

hrou

gh tw

o ne

rves

from

the

med

ulla

of t

he b

rain

.

• Ep

inep

hrin

e in

crea

ses

the

hear

t rat

e to

pre

pare

for v

igor

ous

phys

ical

act

ivity

.

Theo

ry o

f kno

wle

dge:

• O

ur c

urre

nt u

nder

stan

ding

is th

at e

mot

ions

are

the

prod

uct o

f act

ivity

in th

e br

ain

rath

er th

an th

e he

art.

Is k

now

ledg

e ba

sed

on s

cien

ce m

ore

valid

than

kn

owle

dge

base

d on

intu

ition

?

Uti

lizat

ion:

• U

nder

stan

ding

of t

he s

truc

ture

of t

he c

ardi

ovas

cula

r sys

tem

has

allo

wed

the

deve

lopm

ent o

f hea

rt s

urge

ry.

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Bi

olog

yTo

pic

2.2

Wat

erTo

pic

2.3

Carb

ohyd

rate

s an

d lip

ids

Topi

c 6.

4 G

as e

xcha

nge

Topi

c 6.

6 H

orm

ones

, hom

eost

asis

and

repr

oduc

tion

Aim

s:

• A

im 6

: A h

eart

dis

sect

ion

is su

gges

ted

as a

mea

ns o

f stu

dyin

g he

art s

truc

ture

.

• A

im 8

: The

soc

ial i

mpl

icat

ions

of c

oron

ary

hear

t dis

ease

cou

ld b

e di

scus

sed.


Biology guide 75

6.2

The

bloo

d sy

stem

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: W

illia

m H

arve

y’s

disc

over

y of

the

circ

ulat

ion

of th

e bl

ood

with

th

e he

art a

ctin

g as

the

pum

p.

• A

pplic

atio

n: P

ress

ure

chan

ges

in th

e le

ft a

triu

m, l

eft v

entr

icle

and

aor

ta

durin

g th

e ca

rdia

c cy

cle.

• A

pplic

atio

n: C

ause

s an

d co

nseq

uenc

es o

f occ

lusi

on o

f the

cor

onar

y ar

terie

s.

• Sk

ill: I

dent

ifica

tion

of b

lood

ves

sels

as

arte

ries,

cap

illar

ies

or v

eins

from

the

stru

ctur

e of

thei

r wal

ls.

• Sk

ill: R

ecog

nitio

n of

the

cham

bers

and

val

ves

of th

e he

art a

nd th

e bl

ood

vess

els

conn

ecte

d to

it in

dis

sect

ed h

eart

s or

in d

iagr

ams

of h

eart

str

uctu

re.


Biology guide76

Esse

ntia

l ide

a: T

he h

uman

bod

y ha

s st

ruct

ures

and

pro

cess

es th

at re

sist

the

cont

inuo

us th

reat

of i

nvas

ion

by p

atho

gens

.

6.3

Def

ence

aga

inst

infe

ctio

us d

isea

se

Nat

ure

of s

cien

ce:

Risk

s as

soci

ated

with

sci

entif

ic re

sear

ch—

Flor

ey a

nd C

hain

’s te

sts

on th

e sa

fety

of p

enic

illin

wou

ld n

ot b

e co

mpl

iant

with

cur

rent

pro

toco

l on

test

ing.

(4.8

)

Und

erst

andi

ngs:

• Th

e sk

in a

nd m

ucou

s m

embr

anes

form

a p

rimar

y de

fenc

e ag

ains

t pat

hoge

ns

that

cau

se in

fect

ious

dis

ease

.

• Cu

ts in

the

skin

are

sea

led

by b

lood

clo

ttin

g.

• Cl

ottin

g fa

ctor

s ar

e re

leas

ed fr

om p

late

lets

.

• Th

e ca

scad

e re

sults

in th

e ra

pid

conv

ersi

on o

f fib

rinog

en to

fibr

in b

y th

rom

bin.

• In

gest

ion

of p

atho

gens

by

phag

ocyt

ic w

hite

blo

od c

ells

giv

es n

on-s

peci

fic

imm

unity

to d

isea

ses.

• Pr

oduc

tion

of a

ntib

odie

s by

lym

phoc

ytes

in re

spon

se to

par

ticul

ar p

atho

gens

gi

ves

spec

ific

imm

unity

.

• A

ntib

iotic

s bl

ock

proc

esse

s th

at o

ccur

in p

roka

ryot

ic c

ells

but

not

in

euka

ryot

ic c

ells

.

• Vi

ruse

s la

ck a

met

abol

ism

and

can

not t

here

fore

be

trea

ted

with

ant

ibio

tics.

So

me

stra

ins

of b

acte

ria h

ave

evol

ved

with

gen

es th

at c

onfe

r res

ista

nce

to

antib

iotic

s an

d so

me

stra

ins

of b

acte

ria h

ave

mul

tiple

resi

stan

ce.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: C

ause

s an

d co

nseq

uenc

es o

f blo

od c

lot f

orm

atio

n in

cor

onar

y ar

terie

s.

• A

pplic

atio

n: F

lore

y an

d Ch

ain’

s ex

perim

ents

to te

st p

enic

illin

on

bact

eria

l in

fect

ions

in m

ice.

• A

pplic

atio

n: E

ffec

ts o

f HIV

on

the

imm

une

syst

em a

nd m

etho

ds o

f tr

ansm

issi

on.

Inte

rnat

iona

l-m

inde

dnes

s:

• Th

e sp

read

and

con

tain

men

t of d

isea

ses

such

as

bird

flu

requ

ire in

tern

atio

nal

coor

dina

tion

and

com

mun

icat

ion.

Uti

lizat

ion:

• A

n un

ders

tand

ing

of im

mun

ity h

as le

d to

the

deve

lopm

ent o

f vac

cina

tions

.

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Bi

olog

yTo

pic

5.2

Nat

ural

sel

ectio

nCh

emis

try

Topi

c D

2 A

spiri

n an

d pe

nici

llin

Aim

s:

• A

im 8

: The

soc

ial a

s w

ell a

s th

e ec

onom

ic b

enef

its o

f the

con

trol

of b

acte

rial

dise

ases

aro

und

the

wor

ld s

houl

d be

str

esse

d.

• A

im 9

: Sci

ence

has

lim

ited

mea

ns in

the

fight

aga

inst

pat

hoge

ns, a

s sh

own

by

the

spre

ad o

f new

dis

ease

s an

d an

tibio

tic-r

esis

tant

bac

teria

.


Biology guide 77

6.3

Def

ence

aga

inst

infe

ctio

us d

isea

se

Gui

danc

e:

• D

iagr

ams

of s

kin

are

not r

equi

red.

• Su

bgro

ups

of p

hago

cyte

and

lym

phoc

yte

are

not r

equi

red

but s

tude

nts

shou

ld b

e aw

are

that

som

e ly

mph

ocyt

es a

ct a

s m

emor

y ce

lls a

nd c

an q

uick

ly

repr

oduc

e to

form

a c

lone

of p

lasm

a ce

lls if

a p

atho

gen

carr

ying

a s

peci

fic

antig

en is

re-e

ncou

nter

ed.

• Th

e ef

fect

s of

HIV

on

the

imm

une

syst

em s

houl

d be

lim

ited

to a

redu

ctio

n in

the

num

ber o

f act

ive

lym

phoc

ytes

and

a lo

ss o

f the

abi

lity

to p

rodu

ce

antib

odie

s, le

adin

g to

the

deve

lopm

ent o

f AID

S.


Biology guide78

Esse

ntia

l ide

a: T

he lu

ngs

are

activ

ely

vent

ilate

d to

ens

ure

that

gas

exc

hang

e ca

n oc

cur p

assi

vely

.

6.4

Gas

exc

hang

e

Nat

ure

of s

cien

ce:

Obt

ain

evid

ence

for t

heor

ies—

epid

emio

logi

cal s

tudi

es h

ave

cont

ribut

ed to

our

und

erst

andi

ng o

f the

cau

ses

of lu

ng c

ance

r. (1

.8)

Und

erst

andi

ngs:

• Ve

ntila

tion

mai

ntai

ns c

once

ntra

tion

grad

ient

s of

oxy

gen

and

carb

on d

ioxi

de

betw

een

air i

n al

veol

i and

blo

od fl

owin

g in

adj

acen

t cap

illar

ies.

• Ty

pe I

pneu

moc

ytes

are

ext

rem

ely

thin

alv

eola

r cel

ls th

at a

re a

dapt

ed to

ca

rry

out g

as e

xcha

nge.

• Ty

pe II

pne

umoc

ytes

sec

rete

a s

olut

ion

cont

aini

ng s

urfa

ctan

t tha

t cre

ates

a

moi

st s

urfa

ce in

side

the

alve

oli t

o pr

even

t the

sid

es o

f the

alv

eolu

s ad

herin

g to

eac

h ot

her b

y re

duci

ng s

urfa

ce te

nsio

n.

• A

ir is

car

ried

to th

e lu

ngs

in th

e tr

ache

a an

d br

onch

i and

then

to th

e al

veol

i in

bron

chio

les.

• M

uscl

e co

ntra

ctio

ns c

ause

the

pres

sure

cha

nges

insi

de th

e th

orax

that

forc

e ai

r in

and

out o

f the

lung

s to

ven

tilat

e th

em.

• D

iffer

ent m

uscl

es a

re re

quire

d fo

r ins

pira

tion

and

expi

ratio

n be

caus

e m

uscl

es

only

do

wor

k w

hen

they

con

trac

t.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: C

ause

s an

d co

nseq

uenc

es o

f lun

g ca

ncer

.

• A

pplic

atio

n: C

ause

s an

d co

nseq

uenc

es o

f em

phys

ema.

• A

pplic

atio

n: E

xter

nal a

nd in

tern

al in

terc

osta

l mus

cles

, and

dia

phra

gm a

nd

abdo

min

al m

uscl

es a

s ex

ampl

es o

f ant

agon

istic

mus

cle

actio

n.

• Sk

ill: M

onito

ring

of v

entil

atio

n in

hum

ans

at re

st a

nd a

fter

mild

and

vig

orou

s ex

erci

se. (

Prac

tical

6)

Uti

lizat

ion:

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Bi

olog

y To

pic

1.4

Mem

bran

e tr

ansp

ort

Topi

c 1.

6 Ce

ll di

visi

onTo

pic

6.2

The

bloo

d sy

stem

Phys

ics

Topi

c 3.

2 M

odel

ling

a ga

s

Aim

s:

• A

im 8

: The

soc

ial c

onse

quen

ces

of lu

ng c

ance

r and

em

phys

ema

coul

d be

di

scus

sed.


Biology guide 79

6.4

Gas

exc

hang

e

Gui

danc

e:

• Ve

ntila

tion

can

eith

er b

e m

onito

red

by s

impl

e ob

serv

atio

n an

d si

mpl

e ap

para

tus

or b

y da

ta lo

ggin

g w

ith a

spi

rom

eter

or c

hest

bel

t and

pre

ssur

e m

eter

. Ven

tilat

ion

rate

and

tida

l vol

ume

shou

ld b

e m

easu

red,

but

the

term

s vi

tal c

apac

ity a

nd re

sidu

al v

olum

e ar

e no

t exp

ecte

d.

• St

uden

ts s

houl

d be

abl

e to

dra

w a

dia

gram

to s

how

the

stru

ctur

e of

an

alve

olus

and

an

adja

cent

cap

illar

y.


Biology guide80

Esse

ntia

l ide

a: N

euro

ns tr

ansm

it th

e m

essa

ge, s

ynap

ses

mod

ulat

e th

e m

essa

ge.

6.5

Neu

rons

and

syn

apse

s

Nat

ure

of s

cien

ce:

Coop

erat

ion

and

colla

bora

tion

betw

een

grou

ps o

f sci

entis

ts—

biol

ogis

ts a

re c

ontr

ibut

ing

to re

sear

ch in

to m

emor

y an

d le

arni

ng. (

4.3)

Und

erst

andi

ngs:

• N

euro

ns tr

ansm

it el

ectr

ical

impu

lses

.

• Th

e m

yelin

atio

n of

ner

ve fi

bres

allo

ws

for s

alta

tory

con

duct

ion.

• N

euro

ns p

ump

sodi

um a

nd p

otas

sium

ions

acr

oss

thei

r mem

bran

es to

ge

nera

te a

rest

ing

pote

ntia

l.

• A

n ac

tion

pote

ntia

l con

sist

s of d

epol

ariz

atio

n an

d re

pola

rizat

ion

of th

e ne

uron

.

• N

erve

impu

lses

are

act

ion

pote

ntia

ls p

ropa

gate

d al

ong

the

axon

s of

neu

rons

.

• Pr

opag

atio

n of

ner

ve im

puls

es is

the

resu

lt of

loca

l cur

rent

s th

at c

ause

eac

h su

cces

sive

par

t of t

he a

xon

to re

ach

the

thre

shol

d po

tent

ial.

• Sy

naps

es a

re ju

nctio

ns b

etw

een

neur

ons

and

betw

een

neur

ons

and

rece

ptor

or

eff

ecto

r cel

ls.

• W

hen

pres

ynap

tic n

euro

ns a

re d

epol

ariz

ed th

ey re

leas

e a

neur

otra

nsm

itter

in

to th

e sy

naps

e.

• A

ner

ve im

puls

e is

onl

y in

itiat

ed if

the

thre

shol

d po

tent

ial i

s re

ache

d.

App

licat

ions

and

ski

lls:

• Ap

plic

atio

n: S

ecre

tion

and

reab

sorp

tion

of a

cety

lcho

line

by n

euro

ns a

t syn

apse

s.

• A

pplic

atio

n: B

lock

ing

of s

ynap

tic tr

ansm

issi

on a

t cho

liner

gic

syna

pses

in

inse

cts

by b

indi

ng o

f neo

nico

tinoi

d pe

stic

ides

to a

cety

lcho

line

rece

ptor

s.

• Sk

ill: A

naly

sis

of o

scill

osco

pe tr

aces

sho

win

g re

stin

g po

tent

ials

and

act

ion

pote

ntia

ls.

Gui

danc

e:

• Th

e de

tails

of s

truc

ture

of d

iffer

ent t

ypes

of n

euro

n ar

e no

t nee

ded.

• O

nly

chem

ical

syn

apse

s ar

e re

quire

d, n

ot e

lect

rical

, and

they

can

sim

ply

be

refe

rred

to a

s sy

naps

es.

Uti

lizat

ion:

• A

n un

ders

tand

ing

of th

e w

orki

ngs

of n

euro

tran

smitt

ers

and

syna

pses

has

le

d to

the

deve

lopm

ent o

f num

erou

s ph

arm

aceu

tical

s fo

r the

trea

tmen

t of

men

tal d

isor

ders

.

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Bi

olog

y To

pic

1.4

Mem

bran

e tr

ansp

ort

Chem

istr

y To

pic

C6 E

lect

roch

emis

try,

rech

arge

able

bat

terie

s an

d fu

el c

ells

Psyc

holo

gyCo

re: B

iolo

gica

l lev

el o

f ana

lysi

s

Aim

s:

• A

im 8

: The

soc

ial e

ffec

ts o

f the

abu

se o

f psy

choa

ctiv

e dr

ugs

coul

d be

co

nsid

ered

, as

coul

d th

e us

e of

the

neur

otox

in B

otox

for c

osm

etic

trea

tmen

ts.


Biology guide 81

Esse

ntia

l ide

a: H

orm

ones

are

use

d w

hen

sign

als

need

to b

e w

idel

y di

strib

uted

.

6.6

Hor

mon

es, h

omeo

stas

is a

nd re

prod

ucti

on

Nat

ure

of s

cien

ce:

Dev

elop

men

ts in

sci

entif

ic re

sear

ch fo

llow

impr

ovem

ents

in a

ppar

atus

—W

illia

m H

arve

y w

as h

ampe

red

in h

is o

bser

vatio

nal r

esea

rch

into

repr

oduc

tion

by la

ck o

f eq

uipm

ent.

The

mic

rosc

ope

was

inve

nted

17

year

s af

ter h

is d

eath

. (1.

8)

Und

erst

andi

ngs:

• In

sulin

and

glu

cago

n ar

e se

cret

ed b

y β

and

α ce

lls o

f the

pan

crea

s re

spec

tivel

y to

con

trol

blo

od g

luco

se c

once

ntra

tion.

• Th

yrox

in is

sec

rete

d by

the

thyr

oid

glan

d to

regu

late

the

met

abol

ic ra

te a

nd

help

con

trol

bod

y te

mpe

ratu

re.

• Le

ptin

is s

ecre

ted

by c

ells

in a

dipo

se ti

ssue

and

act

s on

the

hypo

thal

amus

of

the

brai

n to

inhi

bit a

ppet

ite.

• M

elat

onin

is s

ecre

ted

by th

e pi

neal

gla

nd to

con

trol

circ

adia

n rh

ythm

s.

• A

gen

e on

the

Y ch

rom

osom

e ca

uses

em

bryo

nic

gona

ds to

dev

elop

as

test

es

and

secr

ete

test

oste

rone

.

• Te

stos

tero

ne c

ause

s pr

e-na

tal d

evel

opm

ent o

f mal

e ge

nita

lia a

nd b

oth

sper

m

prod

uctio

n an

d de

velo

pmen

t of m

ale

seco

ndar

y se

xual

cha

ract

eris

tics

durin

g pu

bert

y.

• Es

trog

en a

nd p

roge

ster

one

caus

e pr

e-na

tal d

evel

opm

ent o

f fem

ale

repr

oduc

tive

orga

ns a

nd fe

mal

e se

cond

ary

sexu

al c

hara

cter

istic

s du

ring

pube

rty.

• Th

e m

enst

rual

cyc

le is

con

trol

led

by n

egat

ive

and

posi

tive

feed

back

m

echa

nism

s in

volv

ing

ovar

ian

and

pitu

itary

hor

mon

es.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: C

ause

s an

d tr

eatm

ent o

f Typ

e I a

nd T

ype

II di

abet

es.

• A

pplic

atio

n: T

estin

g of

lept

in o

n pa

tient

s w

ith c

linic

al o

besi

ty a

nd re

ason

s fo

r th

e fa

ilure

to c

ontr

ol th

e di

seas

e.

Uti

lizat

ion:

• H

orm

ones

are

use

d in

a v

arie

ty o

f the

rapi

es s

uch

as re

plac

emen

t the

rapi

es.

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Bi

olog

yTo

pic

3.2

Chro

mos

omes

Topi

c 3.

3 M

eios

isTo

pic

10.1

Mei

osis

Psyc

holo

gy

Core

: Bio

logi

cal l

evel

of a

naly

sis

Aim

s:

• A

im 8

: Sci

entis

ts a

re a

war

e th

at th

e dr

ugs

wom

en ta

ke in

fert

ility

trea

tmen

t po

se p

oten

tial r

isks

to h

ealth

. Sho

uld

scie

ntifi

c kn

owle

dge

over

ride

com

pass

iona

te c

onsi

dera

tions

in tr

eatin

g in

fert

ile c

oupl

es?


Biology guide82

6.6

Hor

mon

es, h

omeo

stas

is a

nd re

prod

ucti

on

• A

pplic

atio

n: C

ause

s of

jet l

ag a

nd u

se o

f mel

aton

in to

alle

viat

e it.

• A

pplic

atio

n: T

he u

se in

IVF

of d

rugs

to s

uspe

nd th

e no

rmal

sec

retio

n of

ho

rmon

es, f

ollo

wed

by

the

use

of a

rtifi

cial

dos

es o

f hor

mon

es to

indu

ce

supe

rovu

latio

n an

d es

tabl

ish

a pr

egna

ncy.

• A

pplic

atio

n: W

illia

m H

arve

y’s

inve

stig

atio

n of

sex

ual r

epro

duct

ion

in d

eer.

• Sk

ill: A

nnot

ate

diag

ram

s of

the

mal

e an

d fe

mal

e re

prod

uctiv

e sy

stem

to s

how

na

mes

of s

truc

ture

s an

d th

eir f

unct

ions

.

Gui

danc

e:

• Th

e ro

les

of F

SH, L

H, e

stro

gen

and

prog

este

rone

in th

e m

enst

rual

cyc

le a

re

expe

cted

.

• W

illia

m H

arve

y fa

iled

to s

olve

the

mys

tery

of s

exua

l rep

rodu

ctio

n be

caus

e ef

fect

ive

mic

rosc

opes

wer

e no

t ava

ilabl

e w

hen

he w

as w

orki

ng, s

o fu

sion

of

gam

etes

and

sub

sequ

ent e

mbr

yo d

evel

opm

ent r

emai

ned

undi

scov

ered

.

83Biology guide 83

Add

ition

al h

ighe

r lev

el

Topi

c 7:

Nuc

leic

aci

ds

9 ho

urs

Esse

ntia

l ide

a: T

he s

truc

ture

of D

NA

is id

eally

sui

ted

to it

s fu

nctio

n.

7.1

DN

A s

truc

ture

and

repl

icat

ion

Nat

ure

of s

cien

ce:

Mak

ing

care

ful o

bser

vatio

ns—

Rosa

lind

Fran

klin

’s X-

ray

diff

ract

ion

prov

ided

cru

cial

evi

denc

e th

at D

NA

is a

dou

ble

helix

. (1.

8)

Und

erst

andi

ngs:

• N

ucle

osom

es h

elp

to s

uper

coil

the

DN

A.

• D

NA

str

uctu

re s

ugge

sted

a m

echa

nism

for D

NA

repl

icat

ion.

• D

NA

pol

ymer

ases

can

onl

y ad

d nu

cleo

tides

to th

e 3’

end

of a

prim

er.

• D

NA

repl

icat

ion

is c

ontin

uous

on

the

lead

ing

stra

nd a

nd d

isco

ntin

uous

on

the

lagg

ing

stra

nd.

• D

NA

repl

icat

ion

is c

arrie

d ou

t by

a co

mpl

ex s

yste

m o

f enz

ymes

.

• So

me

regi

ons

of D

NA

do

not c

ode

for p

rote

ins

but h

ave

othe

r im

port

ant

func

tions

.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: R

osal

ind

Fran

klin

’s an

d M

auric

e W

ilkin

s’ in

vest

igat

ion

of D

NA

st

ruct

ure

by X

-ray

diff

ract

ion.

• A

pplic

atio

n: U

se o

f nuc

leot

ides

con

tain

ing

dide

oxyr

ibon

ucle

ic a

cid

to s

top

DN

A re

plic

atio

n in

pre

para

tion

of s

ampl

es fo

r bas

e se

quen

cing

.

• A

pplic

atio

n: T

ande

m re

peat

s ar

e us

ed in

DN

A p

rofil

ing.

• Sk

ill: A

naly

sis

of re

sults

of t

he H

ersh

ey a

nd C

hase

exp

erim

ent p

rovi

ding

ev

iden

ce th

at D

NA

is th

e ge

netic

mat

eria

l.

• Sk

ill: U

tiliz

atio

n of

mol

ecul

ar v

isua

lizat

ion

soft

war

e to

ana

lyse

the

asso

ciat

ion

betw

een

prot

ein

and

DN

A w

ithin

a n

ucle

osom

e.

Theo

ry o

f kno

wle

dge:

• H

ighl

y re

petit

ive

sequ

ence

s w

ere

once

cla

ssifi

ed a

s “ju

nk D

NA”

sho

win

g a

degr

ee o

f con

fiden

ce th

at it

had

no

role

. To

wha

t ext

ent d

o th

e la

bels

and

ca

tego

ries

used

in th

e pu

rsui

t of k

now

ledg

e af

fect

the

know

ledg

e w

e ob

tain

?

Uti

lizat

ion:

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Bi

olog

yTo

pic

2.6

Stru

ctur

e of

DN

A a

nd R

NA

Aim

s:

• A

im 6

: Stu

dent

s co

uld

desi

gn m

odel

s to

illu

stra

te th

e st

ages

of D

NA

re

plic

atio

n.

Topic 7: Nucleic acids

Biology guide84

7.1

DN

A s

truc

ture

and

repl

icat

ion

Gui

danc

e:

• D

etai

ls o

f DN

A re

plic

atio

n di

ffer

bet

wee

n pr

okar

yote

s an

d eu

kary

otes

. Onl

y th

e pr

okar

yotic

sys

tem

is e

xpec

ted.

• Th

e pr

otei

ns a

nd e

nzym

es in

volv

ed in

DN

A re

plic

atio

n sh

ould

incl

ude

helic

ase,

DN

A g

yras

e, s

ingl

e st

rand

bin

ding

pro

tein

s, D

NA

prim

ase

and

DN

A

poly

mer

ases

I an

d III

.

• Th

e re

gion

s of

DN

A th

at d

o no

t cod

e fo

r pro

tein

s sh

ould

be

limite

d to

re

gula

tors

of g

ene

expr

essi

on, i

ntro

ns, t

elom

eres

and

gen

es fo

r tRN

As.


Biology guide 85

Esse

ntia

l ide

a: In

form

atio

n st

ored

as

a co

de in

DN

A is

cop

ied

onto

mRN

A.

7.2

Tran

scri

ptio

n an

d ge

ne e

xpre

ssio

n

Nat

ure

of s

cien

ce:

Look

ing

for p

atte

rns,

tren

ds a

nd d

iscr

epan

cies

—th

ere

is m

ount

ing

evid

ence

that

the

envi

ronm

ent c

an tr

igge

r her

itabl

e ch

ange

s in

epi

gene

tic fa

ctor

s. (3

.1)

Und

erst

andi

ngs:

• Tr

ansc

riptio

n oc

curs

in a

5’ t

o 3’

dire

ctio

n.

• N

ucle

osom

es h

elp

to re

gula

te tr

ansc

riptio

n in

euk

aryo

tes.

• Eu

kary

otic

cel

ls m

odify

mRN

A a

fter

tran

scrip

tion.

• Sp

licin

g of

mRN

A in

crea

ses

the

num

ber o

f diff

eren

t pro

tein

s an

org

anis

m c

an

prod

uce.

• G

ene

expr

essi

on is

regu

late

d by

pro

tein

s th

at b

ind

to s

peci

fic b

ase

sequ

ence

s in

DN

A.

• Th

e en

viro

nmen

t of a

cel

l and

of a

n or

gani

sm h

as a

n im

pact

on

gene

ex

pres

sion

.

App

licat

ion

and

skill

s:

• A

pplic

atio

n: T

he p

rom

oter

as

an e

xam

ple

of n

on-c

odin

g D

NA

with

a fu

nctio

n.

• Sk

ill: A

naly

sis

of c

hang

es in

the

DN

A m

ethy

latio

n pa

tter

ns.

Gui

danc

e:

• RN

A p

olym

eras

e ad

ds th

e 5´

end

of t

he fr

ee R

NA

nuc

leot

ide

to th

e 3´

end

of

the

grow

ing

mRN

A m

olec

ule.

Theo

ry o

f kno

wle

dge:

• Th

e na

ture

ver

sus

nurt

ure

deba

te c

once

rnin

g th

e re

lativ

e im

port

ance

of a

n in

divi

dual

’s in

nate

qua

litie

s ve

rsus

thos

e ac

quire

d th

roug

h ex

perie

nces

is

still

und

er d

iscu

ssio

n. Is

it im

port

ant f

or s

cien

ce to

att

empt

to a

nsw

er th

is

ques

tion?

Uti

lizat

ion:

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Bi

olog

yTo

pic

2.7

DN

A re

plic

atio

n, tr

ansc

riptio

n an

d tr

ansl

atio

n


Biology guide86

Esse

ntia

l ide

a: In

form

atio

n tr

ansf

erre

d fr

om D

NA

to m

RNA

is tr

ansl

ated

into

an

amin

o ac

id s

eque

nce.

7.3

Tran

slat

ion

Nat

ure

of s

cien

ce:

Dev

elop

men

ts in

sci

entif

ic re

sear

ch fo

llow

impr

ovem

ents

in c

ompu

ting—

the

use

of c

ompu

ters

has

ena

bled

sci

entis

ts to

mak

e ad

vanc

es in

bio

info

rmat

ics

appl

icat

ions

su

ch a

s lo

catin

g ge

nes

with

in g

enom

es a

nd id

entif

ying

con

serv

ed s

eque

nces

. (3.

7)

Und

erst

andi

ngs:

• In

itiat

ion

of tr

ansl

atio

n in

volv

es a

ssem

bly

of th

e co

mpo

nent

s th

at c

arry

out

th

e pr

oces

s.

• Sy

nthe

sis

of th

e po

lype

ptid

e in

volv

es a

repe

ated

cyc

le o

f eve

nts.

• D

isas

sem

bly

of th

e co

mpo

nent

s fo

llow

s te

rmin

atio

n of

tran

slat

ion.

• Fr

ee ri

boso

mes

syn

thes

ize

prot

eins

for u

se p

rimar

ily w

ithin

the

cell.

• Bo

und

ribos

omes

syn

thes

ize

prot

eins

prim

arily

for s

ecre

tion

or fo

r use

in

lyso

som

es.

• Tr

ansl

atio

n ca

n oc

cur i

mm

edia

tely

aft

er tr

ansc

riptio

n in

pro

kary

otes

due

to

the

abse

nce

of a

nuc

lear

mem

bran

e.

• Th

e se

quen

ce a

nd n

umbe

r of a

min

o ac

ids

in th

e po

lype

ptid

e is

the

prim

ary

stru

ctur

e.

• Th

e se

cond

ary

stru

ctur

e is

the

form

atio

n of

alp

ha h

elic

es a

nd b

eta

plea

ted

shee

ts s

tabi

lized

by

hydr

ogen

bon

ding

.

• Th

e te

rtia

ry s

truc

ture

is th

e fu

rthe

r fol

ding

of t

he p

olyp

eptid

e st

abili

zed

by

inte

ract

ions

bet

wee

n R

grou

ps.

• Th

e qu

ater

nary

str

uctu

re e

xist

s in

pro

tein

s w

ith m

ore

than

one

pol

ypep

tide

chai

n.

App

licat

ion

and

skill

s:

• A

pplic

atio

n: tR

NA

-act

ivat

ing

enzy

mes

illu

stra

te e

nzym

e–su

bstr

ate

spec

ifici

ty

and

the

role

of p

hosp

hory

latio

n.

• Sk

ill: I

dent

ifica

tion

of p

olys

omes

in e

lect

ron

mic

rogr

aphs

of p

roka

ryot

es a

nd

euka

ryot

es.

Uti

lizat

ion:

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Bi

olog

yTo

pic

2.7

DN

A re

plic

atio

n, tr

ansc

riptio

n an

d tr

ansl

atio

nO

ptio

n B:

Bio

tech

nolo

gy a

nd b

ioin

form

atic

s


Biology guide 87

7.3

Tran

slat

ion

• Sk

ill: T

he u

se o

f mol

ecul

ar v

isua

lizat

ion

soft

war

e to

ana

lyse

the

stru

ctur

e of

eu

kary

otic

ribo

som

es a

nd a

tRN

A m

olec

ule.

Gui

danc

e:

• N

ames

of t

he tR

NA

bin

ding

site

s ar

e ex

pect

ed a

s w

ell a

s th

eir r

oles

.

• Ex

ampl

es o

f sta

rt a

nd s

top

codo

ns a

re n

ot re

quire

d.

• Po

lar a

nd n

on-p

olar

am

ino

acid

s ar

e re

leva

nt to

the

bond

s fo

rmed

bet

wee

n R

grou

ps.

• Q

uate

rnar

y st

ruct

ure

may

invo

lve

the

bind

ing

of a

pro

sthe

tic g

roup

to fo

rm a

co

njug

ated

pro

tein

.

Biology guide88

Add

ition

al h

ighe

r lev

el

Topi

c 8:

Met

abol

ism, c

ell r

espi

ratio

n an

d ph

otos

ynth

esis

14

hou

rs

Esse

ntia

l ide

a: M

etab

olic

reac

tions

are

regu

late

d in

resp

onse

to th

e ce

ll’s

need

s.

8.1

Met

abol

ism

Nat

ure

of s

cien

ce:

Dev

elop

men

ts in

sci

entif

ic re

sear

ch fo

llow

impr

ovem

ents

in c

ompu

ting—

deve

lopm

ents

in b

ioin

form

atic

s, s

uch

as th

e in

terr

ogat

ion

of d

atab

ases

, hav

e fa

cilit

ated

re

sear

ch in

to m

etab

olic

pat

hway

s. (3

.8)

Und

erst

andi

ngs:

• M

etab

olic

pat

hway

s co

nsis

t of c

hain

s an

d cy

cles

of e

nzym

e-ca

taly

sed

reac

tions

.

• En

zym

es lo

wer

the

activ

atio

n en

ergy

of t

he c

hem

ical

reac

tions

that

they

ca

taly

se.

• En

zym

e in

hibi

tors

can

be

com

petit

ive

or n

on-c

ompe

titiv

e.

• M

etab

olic

pat

hway

s ca

n be

con

trol

led

by e

nd-p

rodu

ct in

hibi

tion.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: E

nd-p

rodu

ct in

hibi

tion

of th

e pa

thw

ay th

at c

onve

rts

thre

onin

e to

isol

euci

ne.

• A

pplic

atio

n: U

se o

f dat

abas

es to

iden

tify

pote

ntia

l new

ant

i-mal

aria

l dru

gs.

• Sk

ill: C

alcu

latin

g an

d pl

ottin

g ra

tes

of re

actio

n fr

om ra

w e

xper

imen

tal r

esul

ts.

• Sk

ill: D

istin

guis

hing

diff

eren

t typ

es o

f inh

ibiti

on fr

om g

raph

s at

spe

cifie

d su

bstr

ate

conc

entr

atio

n.

Gui

danc

e:

• En

zym

e in

hibi

tion

shou

ld b

e st

udie

d us

ing

one

spec

ific

exam

ple

for

com

petit

ive

and

non-

com

petit

ive

inhi

bitio

n.

Theo

ry o

f kno

wle

dge:

• M

any

met

abol

ic p

athw

ays

have

bee

n de

scrib

ed fo

llow

ing

a se

ries

of c

aref

ully

co

ntro

lled

and

repe

ated

exp

erim

ents

. To

wha

t deg

ree

can

look

ing

at

com

pone

nt p

arts

giv

e us

kno

wle

dge

of th

e w

hole

?

Uti

lizat

ion:

• M

any

enzy

me

inhi

bito

rs h

ave

been

use

d in

med

icin

e. F

or e

xam

ple

etha

nol

has

been

use

d to

act

as

a co

mpe

titiv

e in

hibi

tor f

or a

ntifr

eeze

poi

soni

ng.

• Fo

mep

izol

e, w

hich

is a

n in

hibi

tor o

f alc

ohol

deh

ydro

gena

se, h

as a

lso

been

us

ed fo

r ant

ifree

ze p

oiso

ning

.

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Bi

olog

y To

pic

2.7

DN

A re

plic

atio

n, tr

ansc

riptio

n an

d tr

ansl

atio

nCh

emis

try

Topi

c 6.

1 Co

llisi

on th

eory

and

rate

s of

reac

tion

Aim

s:

• A

im 6

: Exp

erim

ents

on

enzy

me

inhi

bitio

n ca

n be

per

form

ed.

• A

im 7

: Com

pute

r sim

ulat

ions

on

enzy

me

actio

n in

clud

ing

met

abol

ic

inhi

bitio

n ar

e av

aila

ble.

Topic 8: Metabolism, cell respiration and photosynthesis

Biology guide 89

Esse

ntia

l ide

a: E

nerg

y is

con

vert

ed to

a u

sabl

e fo

rm in

cel

l res

pira

tion.

8.2

Cell

resp

irat

ion

Nat

ure

of s

cien

ce:

Para

digm

shi

ft—

the

chem

iosm

otic

theo

ry le

d to

a p

arad

igm

shi

ft in

the

field

of b

ioen

erge

tics.

(2.3

)

Und

erst

andi

ngs:

• Ce

ll re

spira

tion

invo

lves

the

oxid

atio

n an

d re

duct

ion

of e

lect

ron

carr

iers

.

• Ph

osph

oryl

atio

n of

mol

ecul

es m

akes

them

less

sta

ble.

• In

gly

coly

sis,

glu

cose

is c

onve

rted

to p

yruv

ate

in th

e cy

topl

asm

.

• G

lyco

lysi

s gi

ves

a sm

all n

et g

ain

of A

TP w

ithou

t the

use

of o

xyge

n.

• In

aer

obic

cel

l res

pira

tion

pyru

vate

is d

ecar

boxy

late

d an

d ox

idiz

ed, a

nd

conv

erte

d in

to a

cety

l com

poun

d an

d at

tach

ed to

coe

nzym

e A

to fo

rm a

cety

l co

enzy

me

A in

the

link

reac

tion.

• In

the

Kreb

s cy

cle,

the

oxid

atio

n of

ace

tyl g

roup

s is

cou

pled

to th

e re

duct

ion

of h

ydro

gen

carr

iers

, lib

erat

ing

carb

on d

ioxi

de.

• En

ergy

rele

ased

by

oxid

atio

n re

actio

ns is

car

ried

to th

e cr

ista

e of

the

mito

chon

dria

by

redu

ced

NA

D a

nd F

AD

.

• Tr

ansf

er o

f ele

ctro

ns b

etw

een

carr

iers

in th

e el

ectr

on tr

ansp

ort c

hain

in th

e m

embr

ane

of th

e cr

ista

e is

cou

pled

to p

roto

n pu

mpi

ng.

• O

xyge

n is

the

final

ele

ctro

n ac

cept

or.

• In

che

mio

smos

is p

roto

ns d

iffus

e th

roug

h AT

P sy

ntha

se to

gen

erat

e AT

P.

• O

xyge

n is

nee

ded

to b

ind

with

the

free

pro

tons

to m

aint

ain

the

hydr

ogen

gr

adie

nt, r

esul

ting

in th

e fo

rmat

ion

of w

ater

.

• Th

e st

ruct

ure

of th

e m

itoch

ondr

ion

is a

dapt

ed to

the

func

tion

it pe

rfor

ms.

Theo

ry o

f kno

wle

dge:

• Pe

ter M

itche

ll’s

chem

iosm

otic

theo

ry e

ncou

nter

ed y

ears

of o

ppos

ition

bef

ore

it w

as fi

nally

acc

epte

d. F

or w

hat r

easo

ns d

oes

fals

ifica

tion

not a

lway

s re

sult

in

an im

med

iate

acc

epta

nce

of n

ew th

eorie

s or

a p

arad

igm

shi

ft?

Uti

lizat

ion:

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Bi

olog

yTo

pic

2.8

Cell

resp

iratio

nCh

emis

try

Topi

c 9.

1 O

xida

tion

and

redu

ctio

n


Biology guide90

8.2

Cell

resp

irat

ion

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: E

lect

ron

tom

ogra

phy

used

to p

rodu

ce im

ages

of a

ctiv

e m

itoch

ondr

ia.

• Sk

ill: A

naly

sis

of d

iagr

ams

of th

e pa

thw

ays

of a

erob

ic re

spira

tion

to d

educ

e w

here

dec

arbo

xyla

tion

and

oxid

atio

n re

actio

ns o

ccur

.

• Sk

ill: A

nnot

atio

n of

a d

iagr

am o

f a m

itoch

ondr

ion

to in

dica

te th

e ad

apta

tions

to

its

func

tion.

Gui

danc

e:

• Th

e na

mes

of t

he in

term

edia

te c

ompo

unds

in g

ylco

lysi

s an

d th

e Kr

ebs

cycl

e ar

e no

t req

uire

d.


Biology guide 91

Esse

ntia

l ide

a: L

ight

ene

rgy

is c

onve

rted

into

che

mic

al e

nerg

y.

8.3

Phot

osyn

thes

is

Nat

ure

of s

cien

ce:

Dev

elop

men

ts in

scie

ntifi

c re

sear

ch fo

llow

impr

ovem

ents

in a

ppar

atus

—so

urce

s of 14

C an

d au

tora

diog

raph

y en

able

d Ca

lvin

to e

luci

date

the

path

way

s of c

arbo

n fix

atio

n. (1

.8)

Und

erst

andi

ngs:

• Li

ght-

depe

nden

t rea

ctio

ns ta

ke p

lace

in th

e th

ylak

oid

mem

bran

es a

nd th

e sp

ace

insi

de th

em.

• Li

ght-

inde

pend

ent r

eact

ions

take

pla

ce in

the

stro

ma.

• Re

duce

d N

AD

P an

d AT

P ar

e pr

oduc

ed in

the

light

-dep

ende

nt re

actio

ns.

• A

bsor

ptio

n of

ligh

t by

phot

osys

tem

s ge

nera

tes

exci

ted

elec

tron

s.

• Ph

otol

ysis

of w

ater

gen

erat

es e

lect

rons

for u

se in

the

light

-dep

ende

nt

reac

tions

.

• Tr

ansf

er o

f exc

ited

elec

tron

s oc

curs

bet

wee

n ca

rrie

rs in

thyl

akoi

d m

embr

anes

.

• Ex

cite

d el

ectr

ons

from

Pho

tosy

stem

II a

re u

sed

to c

ontr

ibut

e to

gen

erat

e a

prot

on g

radi

ent.

• AT

P sy

ntha

se in

thyl

akoi

ds g

ener

ates

ATP

usi

ng th

e pr

oton

gra

dien

t.

• Ex

cite

d el

ectr

ons

from

Pho

tosy

stem

I ar

e us

ed to

redu

ce N

AD

P.

• In

the

light

-inde

pend

ent r

eact

ions

a c

arbo

xyla

se c

atal

yses

the

carb

oxyl

atio

n of

ribu

lose

bis

phos

phat

e.

• G

lyce

rate

3-p

hosp

hate

is re

duce

d to

trio

se p

hosp

hate

usi

ng re

duce

d N

AD

P an

d AT

P.

• Tr

iose

pho

spha

te is

use

d to

rege

nera

te R

uBP

and

prod

uce

carb

ohyd

rate

s.

• Ri

bulo

se b

isph

osph

ate

is re

form

ed u

sing

ATP

.

• Th

e st

ruct

ure

of th

e ch

loro

plas

t is

adap

ted

to it

s fu

nctio

n in

pho

tosy

nthe

sis.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: C

alvi

n’s

expe

rimen

t to

eluc

idat

e th

e ca

rbox

ylat

ion

of R

uBP.

• Sk

ill: A

nnot

atio

n of

a d

iagr

am to

indi

cate

the

adap

tatio

ns o

f a c

hlor

opla

st to

its

func

tion.

Theo

ry o

f kno

wle

dge:

• Th

e lo

llipo

p ex

perim

ent u

sed

to w

ork

out t

he b

ioch

emic

al d

etai

ls o

f the

Ca

lvin

cyc

le s

how

s co

nsid

erab

le c

reat

ivity

. To

wha

t ext

ent i

s th

e cr

eatio

n of

an

ele

gant

pro

toco

l sim

ilar t

o th

e cr

eatio

n of

a w

ork

of a

rt?

Uti

lizat

ion:

• Th

e G

loba

l Art

ifici

al P

hoto

synt

hesi

s (G

AP)

pro

ject

aim

s to

cre

ate

an a

rtifi

cial

“le

af” w

ithin

the

next

dec

ade.

An

elec

tron

ic v

ersi

on o

f the

leaf

that

cre

ates

ox

ygen

and

hyd

roge

n fr

om w

ater

and

sun

light

has

alre

ady

been

inve

nted

an

d w

ill b

e de

velo

ped

for u

se in

the

next

dec

ade.

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Bi

olog

yTo

pic

2.9

Phot

osyn

thes

isTo

pic

4.2

Ener

gy fl

owTo

pic

4.3

Carb

on c

yclin

g Ch

emis

try

Topi

c 9.

1 O

xida

tion

and

redu

ctio

n

Aim

s:

• A

im 6

: Hill

´s m

etho

d de

mon

stra

ting

elec

tron

tran

sfer

in c

hlor

opla

sts

by o

bser

ving

DCP

IP re

duct

ion,

imm

obili

zatio

n of

a c

ultu

re o

f an

alga

su

ch a

s Sc

ened

esm

us in

alg

inat

e be

ads

and

mea

sure

men

t of t

he ra

te o

f ph

otos

ynth

esis

by

mon

itorin

g th

eir e

ffec

t on

hydr

ogen

carb

onat

e in

dica

tor

are

all p

ossi

ble

expe

rimen

ts.

Biology guide92

Add

ition

al h

ighe

r lev

el

Topi

c 9:

Pla

nt b

iolo

gy

13 h

ours

Esse

ntia

l ide

a: S

truc

ture

and

func

tion

are

corr

elat

ed in

the

xyle

m o

f pla

nts.

9.1

Tran

spor

t in

the

xyle

m o

f pla

nts

Nat

ure

of s

cien

ce:

Use

mod

els

as re

pres

enta

tions

of t

he re

al w

orld

—m

echa

nism

s in

volv

ed in

wat

er tr

ansp

ort i

n th

e xy

lem

can

be

inve

stig

ated

usi

ng a

ppar

atus

and

mat

eria

ls th

at s

how

si

mila

ritie

s in

str

uctu

re to

pla

nt ti

ssue

s. (1

.10)

Und

erst

andi

ngs:

• Tr

ansp

iratio

n is

the

inev

itabl

e co

nseq

uenc

e of

gas

exc

hang

e in

the

leaf

.

• Pl

ants

tran

spor

t wat

er fr

om th

e ro

ots

to th

e le

aves

to re

plac

e lo

sses

from

tr

ansp

iratio

n.

• Th

e co

hesi

ve p

rope

rty

of w

ater

and

the

stru

ctur

e of

the

xyle

m v

esse

ls a

llow

tr

ansp

ort u

nder

tens

ion.

• Th

e ad

hesi

ve p

rope

rty

of w

ater

and

eva

pora

tion

gene

rate

tens

ion

forc

es in

le

af c

ell w

alls

.

• Ac

tive

upta

ke o

f min

eral

ions

in th

e ro

ots c

ause

s abs

orpt

ion

of w

ater

by

osm

osis.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: A

dapt

atio

ns o

f pla

nts

in d

eser

ts a

nd in

sal

ine

soils

for w

ater

co

nser

vatio

n.

• A

pplic

atio

n: M

odel

s of

wat

er tr

ansp

ort i

n xy

lem

usi

ng s

impl

e ap

para

tus

incl

udin

g bl

ottin

g or

filte

r pap

er, p

orou

s po

ts a

nd c

apill

ary

tubi

ng.

• Sk

ill: D

raw

ing

the

stru

ctur

e of

prim

ary

xyle

m v

esse

ls in

sec

tions

of s

tem

s ba

sed

on m

icro

scop

e im

ages

.

• Sk

ill: M

easu

rem

ent o

f tra

nspi

ratio

n ra

tes

usin

g po

tom

eter

s. (P

ract

ical

7)

• Sk

ill: D

esig

n of

an

expe

rimen

t to

test

hyp

othe

ses

abou

t the

eff

ect o

f te

mpe

ratu

re o

r hum

idity

on

tran

spira

tion

rate

s.

Uti

lizat

ion:

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Bi

olog

yTo

pic

2.2

Wat

erTo

pics

2.9

and

8.3

Pho

tosy

nthe

sis

Aim

s:

• A

im 7

: The

intr

oduc

tion

of im

age

proc

essi

ng s

oftw

are

and

digi

tal

mic

rosc

opes

incr

ease

s fu

rthe

r the

abi

lity

to g

athe

r mor

e da

ta to

ens

ure

relia

bilit

y.

• A

im 6

: Mea

sure

men

t of s

tom

atal

ape

rtur

es a

nd th

e di

strib

utio

n of

sto

mat

a us

ing

leaf

cas

ts, i

nclu

ding

repl

icat

e m

easu

rem

ents

to e

nhan

ce re

liabi

lity,

are

po

ssib

le e

xper

imen

ts.

Topic 9: Plant biology

Biology guide 93

Esse

ntia

l ide

a: S

truc

ture

and

func

tion

are

corr

elat

ed in

the

phlo

em o

f pla

nts.

9.2

Tran

spor

t in

the

phlo

em o

f pla

nts

Nat

ure

of s

cien

ce:

Dev

elop

men

ts in

sci

entif

ic re

sear

ch fo

llow

impr

ovem

ents

in a

ppar

atus

—ex

perim

enta

l met

hods

for m

easu

ring

phlo

em tr

ansp

ort r

ates

usi

ng a

phid

sty

lets

and

ra

dioa

ctiv

ely-

labe

lled

carb

on d

ioxi

de w

ere

only

pos

sibl

e w

hen

radi

oiso

tope

s be

cam

e av

aila

ble.

(1.8

)

Und

erst

andi

ngs:

• Pl

ants

tran

spor

t org

anic

com

poun

ds fr

om s

ourc

es to

sin

ks.

• In

com

pres

sibi

lity

of w

ater

allo

ws

tran

spor

t alo

ng h

ydro

stat

ic p

ress

ure

grad

ient

s.

• A

ctiv

e tr

ansp

ort i

s us

ed to

load

org

anic

com

poun

ds in

to p

hloe

m s

ieve

tube

s at

the

sour

ce.

• H

igh

conc

entr

atio

ns o

f sol

utes

in th

e ph

loem

at t

he s

ourc

e le

ad to

wat

er

upta

ke b

y os

mos

is.

• Ra

ised

hyd

rost

atic

pre

ssur

e ca

uses

the

cont

ents

of t

he p

hloe

m to

flow

to

war

ds s

inks

.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: S

truc

ture

–fun

ctio

n re

latio

nshi

ps o

f phl

oem

sie

ve tu

bes.

• Sk

ill: I

dent

ifica

tion

of x

ylem

and

phl

oem

in m

icro

scop

e im

ages

of s

tem

and

ro

ot.

• Sk

ill: A

naly

sis

of d

ata

from

exp

erim

ents

mea

surin

g ph

loem

tran

spor

t rat

es

usin

g ap

hid

styl

ets

and

radi

oact

ivel

y-la

belle

d ca

rbon

dio

xide

.

Uti

lizat

ion:

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Bi

olog

yTo

pic

1.4

Mem

bran

e tr

ansp

ort


Biology guide94

Esse

ntia

l ide

a: P

lant

s ad

apt t

heir

grow

th to

env

ironm

enta

l con

ditio

ns.

9.3

Gro

wth

in p

lant

s

Nat

ure

of s

cien

ce:

Dev

elop

men

ts in

sci

entif

ic re

sear

ch fo

llow

impr

ovem

ents

in a

naly

sis

and

dedu

ctio

n—im

prov

emen

ts in

ana

lytic

al te

chni

ques

allo

win

g th

e de

tect

ion

of tr

ace

amou

nts

of

subs

tanc

es h

as le

d to

adv

ance

s in

the

unde

rsta

ndin

g of

pla

nt h

orm

ones

and

thei

r eff

ect o

n ge

ne e

xpre

ssio

n. (1

.8)

Und

erst

andi

ngs:

• U

ndiff

eren

tiate

d ce

lls in

the

mer

iste

ms

of p

lant

s al

low

inde

term

inat

e gr

owth

.

• M

itosi

s an

d ce

ll di

visi

on in

the

shoo

t ape

x pr

ovid

e ce

lls n

eede

d fo

r ext

ensi

on

of th

e st

em a

nd d

evel

opm

ent o

f lea

ves.

• Pl

ant h

orm

ones

con

trol

gro

wth

in th

e sh

oot a

pex.

• Pl

ant s

hoot

s re

spon

d to

the

envi

ronm

ent b

y tr

opis

ms.

• Au

xin

efflu

x pu

mps

can

set

up

conc

entr

atio

n gr

adie

nts

of a

uxin

in p

lant

tis

sue.

• Au

xin

influ

ence

s ce

ll gr

owth

rate

s by

cha

ngin

g th

e pa

tter

n of

gen

e ex

pres

sion

.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: M

icro

prop

agat

ion

of p

lant

s us

ing

tissu

e fr

om th

e sh

oot a

pex,

nu

trie

nt a

gar g

els

and

grow

th h

orm

ones

.

• A

pplic

atio

n: U

se o

f mic

ropr

opag

atio

n fo

r rap

id b

ulki

ng u

p of

new

var

ietie

s,

prod

uctio

n of

viru

s-fr

ee s

trai

ns o

f exi

stin

g va

rietie

s an

d pr

opag

atio

n of

or

chid

s an

d ot

her r

are

spec

ies.

Gui

danc

e:

• Au

xin

is th

e on

ly n

amed

hor

mon

e th

at is

exp

ecte

d.

Theo

ry o

f kno

wle

dge:

• Pl

ants

com

mun

icat

e ch

emic

ally

bot

h in

tern

ally

and

ext

erna

lly. T

o w

hat e

xten

t ca

n pl

ants

be

said

to h

ave

lang

uage

?

Uti

lizat

ion:

• M

icro

prop

agat

ion

is u

sed

for r

apid

bul

king

up

of n

ew v

arie

ties

of p

lant

.

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Bi

olog

yTo

pic

3.5

Gen

etic

mod

ifica

tion

and

biot

echn

olog

y

Aim

s:

• A

im 6

: Inv

estig

atio

ns in

to tr

opis

ms

coul

d be

car

ried

out.


Biology guide 95

Esse

ntia

l ide

a: R

epro

duct

ion

in fl

ower

ing

plan

ts is

influ

ence

d by

the

biot

ic a

nd a

biot

ic e

nviro

nmen

t.

9.4

Repr

oduc

tion

in p

lant

s

Nat

ure

of s

cien

ce:

Para

digm

shi

ft—

mor

e th

an 8

5% o

f the

wor

ld’s

250,

000

spec

ies

of fl

ower

ing

plan

t dep

end

on p

ollin

ator

s fo

r rep

rodu

ctio

n. T

his

know

ledg

e ha

s le

d to

pro

tect

ing

entir

e ec

osys

tem

s ra

ther

than

indi

vidu

al s

peci

es. (

2.3)

Und

erst

andi

ngs:

• Fl

ower

ing

invo

lves

a c

hang

e in

gen

e ex

pres

sion

in th

e sh

oot a

pex.

• Th

e sw

itch

to fl

ower

ing

is a

resp

onse

to th

e le

ngth

of l

ight

and

dar

k pe

riods

in

man

y pl

ants

.

• Su

cces

s in

pla

nt re

prod

uctio

n de

pend

s on

pol

linat

ion,

fert

iliza

tion

and

seed

di

sper

sal.

• M

ost f

low

erin

g pl

ants

use

mut

ualis

tic re

latio

nshi

ps w

ith p

ollin

ator

s in

sex

ual

repr

oduc

tion.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: M

etho

ds u

sed

to in

duce

sho

rt-d

ay p

lant

s to

flow

er o

ut o

f sea

son.

• Sk

ill: D

raw

ing

inte

rnal

str

uctu

re o

f see

ds.

• Sk

ill: D

raw

ing

of h

alf-v

iew

s of

ani

mal

-pol

linat

ed fl

ower

s.

• Sk

ill: D

esig

n of

exp

erim

ents

to te

st h

ypot

hese

s ab

out f

acto

rs a

ffec

ting

germ

inat

ion.

Gui

danc

e:

• St

uden

ts s

houl

d un

ders

tand

the

diff

eren

ces

betw

een

polli

natio

n, fe

rtili

zatio

n an

d se

ed d

ispe

rsal

but

are

not

requ

ired

to k

now

the

deta

ils o

f eac

h pr

oces

s.

• Fl

ower

ing

in s

o-ca

lled

shor

t-da

y pl

ants

suc

h as

chr

ysan

them

ums,

is

stim

ulat

ed b

y lo

ng n

ight

s ra

ther

than

sho

rt d

ays.

Uti

lizat

ion:

• Th

e U

nive

rsity

of G

öttin

gen,

in G

erm

any,

con

duct

ed a

n ex

tens

ive

revi

ew

of s

cien

tific

stu

dies

from

200

cou

ntrie

s fo

r 115

of t

he le

adin

g gl

obal

cro

ps

in 2

005.

The

y fo

und

that

87

of th

e cr

op p

lant

s de

pend

to s

ome

degr

ee

upon

ani

mal

pol

linat

ion,

incl

udin

g be

es. T

his

acco

unts

for o

ne-t

hird

of c

rop

prod

uctio

n gl

obal

ly.

Biology guide96

Add

ition

al h

ighe

r lev

el

Topi

c 10

: Gen

etic

s an

d ev

olut

ion

8 ho

urs

Esse

ntia

l ide

a: M

eios

is le

ads

to in

depe

nden

t ass

ortm

ent o

f chr

omos

omes

and

uni

que

com

posi

tion

of a

llele

s in

dau

ghte

r cel

ls.

10.1

Mei

osis

Nat

ure

of s

cien

ce:

Mak

ing

care

ful o

bser

vatio

ns—

care

ful o

bser

vatio

n an

d re

cord

kee

ping

turn

ed u

p an

omal

ous

data

that

Men

del’s

law

of i

ndep

ende

nt a

ssor

tmen

t cou

ld n

ot a

ccou

nt fo

r. Th

omas

Hun

t Mor

gan

deve

lope

d th

e no

tion

of li

nked

gen

es to

acc

ount

for t

he a

nom

alie

s. (1

.8)

Und

erst

andi

ngs:

• Ch

rom

osom

es re

plic

ate

in in

terp

hase

bef

ore

mei

osis

.

• Cr

ossi

ng o

ver i

s th

e ex

chan

ge o

f DN

A m

ater

ial b

etw

een

non-

sist

er

hom

olog

ous

chro

mat

ids.

• Cr

ossi

ng o

ver p

rodu

ces

new

com

bina

tions

of a

llele

s on

the

chro

mos

omes

of

the

hapl

oid

cells

.

• Ch

iasm

ata

form

atio

n be

twee

n no

n-si

ster

chr

omat

ids

can

resu

lt in

an

exch

ange

of a

llele

s.

• H

omol

ogou

s ch

rom

osom

es s

epar

ate

in m

eios

is I.

• Si

ster

chr

omat

ids

sepa

rate

in m

eios

is II

.

• In

depe

nden

t ass

ortm

ent o

f gen

es is

due

to th

e ra

ndom

orie

ntat

ion

of p

airs

of

hom

olog

ous

chro

mos

omes

in m

eios

is I.

App

licat

ions

and

ski

lls:

• Sk

ill: D

raw

ing

diag

ram

s to

sho

w c

hias

mat

a fo

rmed

by

cros

sing

ove

r.

Gui

danc

e:

• D

iagr

ams

of c

hias

mat

a sh

ould

sho

w s

iste

r chr

omat

ids

still

clo

sely

alig

ned,

ex

cept

at t

he p

oint

whe

re c

ross

ing

over

occ

urre

d an

d a

chia

sma

was

form

ed.

Uti

lizat

ion:

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Bi

olog

yTo

pic

1.6

Cell

divi

sion

Topi

c 3.

3 M

eios

isTo

pic

11.4

Sex

ual r

epro

duct

ion

Aim

s:

• A

im 6

: Sta

inin

g of

lily

ant

hers

or o

ther

tiss

ue c

onta

inin

g ge

rm-li

ne c

ells

and

m

icro

scop

e ex

amin

atio

n to

obs

erve

cel

ls in

mei

osis

are

pos

sibl

e ac

tiviti

es.

Topic 10: Genetics and evolution

Biology guide 97

Esse

ntia

l ide

a: G

enes

may

be

linke

d or

unl

inke

d an

d ar

e in

herit

ed a

ccor

ding

ly.

10.2

Inhe

rita

nce

Nat

ure

of s

cien

ce:

Look

ing

for p

atte

rns,

tren

ds a

nd d

iscr

epan

cies

—M

ende

l use

d ob

serv

atio

ns o

f the

nat

ural

wor

ld to

find

and

exp

lain

pat

tern

s an

d tr

ends

. Sin

ce th

en, s

cien

tists

hav

e lo

oked

for d

iscr

epan

cies

and

ask

ed q

uest

ions

bas

ed o

n fu

rthe

r obs

erva

tions

to s

how

exc

eptio

ns to

the

rule

s. F

or e

xam

ple,

Mor

gan

disc

over

ed n

on-M

ende

lian

ratio

s in

hi

s ex

perim

ents

with

Dro

soph

ila. (

3.1)

Und

erst

andi

ngs:

• G

ene

loci

are

sai

d to

be

linke

d if

on th

e sa

me

chro

mos

ome.

• U

nlin

ked

gene

s se

greg

ate

inde

pend

ently

as

a re

sult

of m

eios

is.

• Va

riatio

n ca

n be

dis

cret

e or

con

tinuo

us.

• Th

e ph

enot

ypes

of p

olyg

enic

cha

ract

eris

tics

tend

to s

how

con

tinuo

us

varia

tion.

• Ch

i-squ

ared

test

s ar

e us

ed to

det

erm

ine

whe

ther

the

diff

eren

ce b

etw

een

an

obse

rved

and

exp

ecte

d fr

eque

ncy

dist

ribut

ion

is s

tatis

tical

ly s

igni

fican

t.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: M

orga

n’s

disc

over

y of

non

-Men

delia

n ra

tios

in D

roso

phila

.

• A

pplic

atio

n: C

ompl

etio

n an

d an

alys

is o

f Pun

nett

squ

ares

for d

ihyb

rid tr

aits

.

• A

pplic

atio

n: P

olyg

enic

trai

ts s

uch

as h

uman

hei

ght m

ay a

lso

be in

fluen

ced

by

envi

ronm

enta

l fac

tors

.

• Sk

ill: C

alcu

latio

n of

the

pred

icte

d ge

noty

pic

and

phen

otyp

ic ra

tio o

f off

sprin

g of

dih

ybrid

cro

sses

invo

lvin

g un

linke

d au

toso

mal

gen

es.

• Sk

ill: I

dent

ifica

tion

of re

com

bina

nts

in c

ross

es in

volv

ing

two

linke

d ge

nes.

• Sk

ill: U

se o

f a c

hi-s

quar

ed te

st o

n da

ta fr

om d

ihyb

rid c

ross

es.

Theo

ry o

f kno

wle

dge:

• Th

e la

w o

f ind

epen

dent

ass

ortm

ent w

as s

oon

foun

d to

hav

e ex

cept

ions

w

hen

look

ing

at li

nked

gen

es. W

hat i

s th

e di

ffer

ence

bet

wee

n a

law

and

a

theo

ry in

sci

ence

?

Uti

lizat

ion:

• A

n un

ders

tand

ing

of in

herit

ance

allo

wed

farm

ers

to s

elec

tivel

y br

eed

thei

r liv

esto

ck fo

r spe

cific

cha

ract

eris

tics.

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Bi

olog

yTo

pic

3.4

Inhe

ritan

ce

Aim

s:

• A

im 4

: Use

ana

lytic

al s

kills

to s

olve

gen

etic

cro

sses

.

• A

im 8

: Eth

ical

issu

es a

rise

in th

e pr

even

tion

of th

e in

herit

ance

of g

enet

ic

diso

rder

s.


Biology guide98

10.2

Inhe

rita

nce

Gui

danc

e:

• A

llele

s ar

e us

ually

sho

wn

side

by

side

in d

ihyb

rid c

ross

es, f

or e

xam

ple,

TtB

b.

In re

pres

entin

g cr

osse

s in

volv

ing

linka

ge, i

t is

mor

e co

mm

on to

sho

w th

em a

s ve

rtic

al p

airs

, for

exa

mpl

e:

• Th

is fo

rmat

will

be

used

in e

xam

inat

ion

pape

rs, o

r stu

dent

s w

ill b

e gi

ven

suff

icie

nt in

form

atio

n to

allo

w th

em to

ded

uce

whi

ch a

llele

s ar

e lin

ked.


Biology guide 99

Esse

ntia

l ide

a: G

ene

pool

s ch

ange

ove

r tim

e.

10.3

Gen

e po

ols

and

spec

iati

on

Nat

ure

of s

cien

ce:

Look

ing

for p

atte

rns,

tren

ds a

nd d

iscr

epan

cies

—pa

tter

ns o

f chr

omos

ome

num

ber i

n so

me

gene

ra c

an b

e ex

plai

ned

by s

peci

atio

n du

e to

pol

yplo

idy.

(3.1)

Und

erst

andi

ngs:

• A

gen

e po

ol c

onsi

sts

of a

ll th

e ge

nes

and

thei

r diff

eren

t alle

les,

pre

sent

in a

n in

terb

reed

ing

popu

latio

n.

• Ev

olut

ion

requ

ires

that

alle

le fr

eque

ncie

s ch

ange

with

tim

e in

pop

ulat

ions

.

• Re

prod

uctiv

e is

olat

ion

of p

opul

atio

ns c

an b

e te

mpo

ral,

beha

viou

ral o

r ge

ogra

phic

.

• Sp

ecia

tion

due

to d

iver

genc

e of

isol

ated

pop

ulat

ions

can

be

grad

ual.

• Sp

ecia

tion

can

occu

r abr

uptly

.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: Id

entif

ying

exa

mpl

es o

f dire

ctio

nal,

stab

ilizi

ng a

nd d

isru

ptiv

e se

lect

ion.

• A

pplic

atio

n: S

peci

atio

n in

the

genu

s Al

lium

by

poly

ploi

dy.

• Sk

ill: C

ompa

rison

of a

llele

freq

uenc

ies

of g

eogr

aphi

cally

isol

ated

pop

ulat

ions

.

Gui

danc

e:

• Pu

nctu

ated

equ

ilibr

ium

impl

ies

long

per

iods

with

out a

ppre

ciab

le c

hang

e an

d sh

ort p

erio

ds o

f rap

id e

volu

tion.

Theo

ry o

f kno

wle

dge:

• Pu

nctu

ated

equ

ilibr

ium

was

long

con

side

red

an a

ltern

ativ

e th

eory

of

evol

utio

n an

d a

chal

leng

e to

the

long

est

ablis

hed

para

digm

of D

arw

inia

n gr

adua

lism

. How

do

para

digm

shi

fts

proc

eed

in s

cien

ce a

nd w

hat f

acto

rs a

re

invo

lved

in th

eir s

ucce

ss?

Uti

lizat

ion:

• M

any

crop

spe

cies

hav

e be

en c

reat

ed to

be

poly

ploi

d. P

olyp

loid

y in

crea

ses

alle

lic d

iver

sity

and

per

mits

nov

el p

heno

type

s to

be

gene

rate

d. It

als

o le

ads

to h

ybrid

vig

our.

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Bi

olog

yTo

pic

5.1

Evid

ence

for e

volu

tion

Biology guide100

Add

ition

al h

ighe

r lev

el

Topi

c 11

: Ani

mal

phy

siol

ogy

16 h

ours

Esse

ntia

l ide

a: Im

mun

ity is

bas

ed o

n re

cogn

ition

of s

elf a

nd d

estr

uctio

n of

fore

ign

mat

eria

l.

11.1

Ant

ibod

y pr

oduc

tion

and

vac

cina

tion

Nat

ure

of s

cien

ce:

Cons

ider

eth

ical

impl

icat

ions

of r

esea

rch—

Jenn

er te

sted

his

vac

cine

for s

mal

lpox

on

a ch

ild. (

4.5)

Und

erst

andi

ngs:

• Ev

ery

orga

nism

has

uni

que

mol

ecul

es o

n th

e su

rfac

e of

its

cells

.

• Pa

thog

ens

can

be s

peci

es-s

peci

fic a

lthou

gh o

ther

s ca

n cr

oss

spec

ies

barr

iers

.

• B

lym

phoc

ytes

are

act

ivat

ed b

y T

lym

phoc

ytes

in m

amm

als.

• A

ctiv

ated

B c

ells

mul

tiply

to fo

rm c

lone

s of

pla

sma

cells

and

mem

ory

cells

.

• Pl

asm

a ce

lls s

ecre

te a

ntib

odie

s.

• A

ntib

odie

s ai

d th

e de

stru

ctio

n of

pat

hoge

ns.

• W

hite

cel

ls re

leas

e hi

stam

ine

in re

spon

se to

alle

rgen

s.

• H

ista

min

es c

ause

alle

rgic

sym

ptom

s.

• Im

mun

ity d

epen

ds u

pon

the

pers

iste

nce

of m

emor

y ce

lls.

• Va

ccin

es c

onta

in a

ntig

ens

that

trig

ger i

mm

unity

but

do

not c

ause

the

dise

ase.

• Fu

sion

of a

tum

our c

ell w

ith a

n an

tibod

y-pr

oduc

ing

plas

ma

cell

crea

tes

a hy

brid

oma

cell.

• M

onoc

lona

l ant

ibod

ies

are

prod

uced

by

hybr

idom

a ce

lls.

Inte

rnat

iona

l-m

inde

dnes

s:

• Th

e W

orld

Hea

lth O

rgan

izat

ion

initi

ated

the

cam

paig

n fo

r the

glo

bal

erad

icat

ion

of s

mal

lpox

in 1

967.

The

cam

paig

n w

as d

eem

ed a

suc

cess

in 1

977,

on

ly 1

0 ye

ars

late

r.

Uti

lizat

ion:

• H

uman

vac

cine

s ar

e of

ten

prod

uced

usi

ng th

e im

mun

e re

spon

ses

of o

ther

an

imal

s.

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Bi

olog

yTo

pic

6.3

Def

ence

aga

inst

infe

ctio

us d

isea

seTo

pic

11.4

Sex

ual r

epro

duct

ion

Geo

grap

hyPa

rt 2

F: T

he g

eogr

aphy

of f

ood

and

heal

th

Aim

s:

• A

im 7

: Use

of d

atab

ases

to a

naly

se e

pide

mio

logi

cal d

ata.

Topic 11: Animal physiology

Biology guide 101

11.1

Ant

ibod

y pr

oduc

tion

and

vac

cina

tion

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: S

mal

lpox

was

the

first

infe

ctio

us d

isea

se o

f hum

ans

to h

ave

been

er

adic

ated

by

vacc

inat

ion.

• A

pplic

atio

n: M

onoc

lona

l ant

ibod

ies

to H

CG a

re u

sed

in p

regn

ancy

test

kits

.

• A

pplic

atio

n: A

ntig

ens

on th

e su

rfac

e of

red

bloo

d ce

lls s

timul

ate

antib

ody

prod

uctio

n in

a p

erso

n w

ith a

diff

eren

t blo

od g

roup

.

• Sk

ill: A

naly

sis

of e

pide

mio

logi

cal d

ata

rela

ted

to v

acci

natio

n pr

ogra

mm

es.

Gui

danc

e:

• Li

mit

the

imm

une

resp

onse

to m

amm

als.


Biology guide102

Esse

ntia

l ide

a: T

he ro

les

of th

e m

uscu

losk

elet

al s

yste

m a

re m

ovem

ent,

supp

ort a

nd p

rote

ctio

n.

11.2

Mov

emen

t

Nat

ure

of s

cien

ce:

Dev

elop

men

ts in

scie

ntifi

c re

sear

ch fo

llow

impr

ovem

ents

in a

ppar

atus

—flu

ores

cent

cal

cium

ions

hav

e be

en u

sed

to st

udy

the

cycl

ic in

tera

ctio

ns in

mus

cle

cont

ract

ion.

(1.8

)

Und

erst

andi

ngs:

• Bo

nes

and

exos

kele

tons

pro

vide

anc

hora

ge fo

r mus

cles

and

act

as

leve

rs.

• Sy

novi

al jo

ints

allo

w c

erta

in m

ovem

ents

but

not

oth

ers.

• M

ovem

ent o

f the

bod

y re

quire

s m

uscl

es to

wor

k in

ant

agon

istic

pai

rs.

• Sk

elet

al m

uscl

e fib

res

are

mul

tinuc

leat

e an

d co

ntai

n sp

ecia

lized

end

opla

smic

re

ticul

um.

• M

uscl

e fib

res

cont

ain

man

y m

yofib

rils.

• Ea

ch m

yofib

ril is

mad

e up

of c

ontr

actil

e sa

rcom

eres

.

• Th

e co

ntra

ctio

n of

the

skel

etal

mus

cle

is a

chie

ved

by th

e sl

idin

g of

act

in a

nd

myo

sin

filam

ents

.

• AT

P hy

drol

ysis

and

cro

ss b

ridge

form

atio

n ar

e ne

cess

ary

for t

he fi

lam

ents

to

slid

e.

• Ca

lciu

m io

ns a

nd th

e pr

otei

ns tr

opom

yosi

n an

d tr

opon

in c

ontr

ol m

uscl

e co

ntra

ctio

ns.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: A

ntag

onis

tic p

airs

of m

uscl

es in

an

inse

ct le

g.

• Sk

ill: A

nnot

atio

n of

a d

iagr

am o

f the

hum

an e

lbow

.

• Sk

ill: D

raw

ing

labe

lled

diag

ram

s of

the

stru

ctur

e of

a s

arco

mer

e.

• Sk

ill: A

naly

sis

of e

lect

ron

mic

rogr

aphs

to fi

nd th

e st

ate

of c

ontr

actio

n of

m

uscl

e fib

res.

Aim

s:

• A

im 7

: Use

of g

rip s

tren

gth

data

logg

ers

to a

sses

s m

uscl

e fa

tigue

.

• A

im 7

: Use

of a

nim

atio

ns to

vis

ualiz

e co

ntra

ctio

n.


Biology guide 103

11.2

Mov

emen

t

Gui

danc

e:

• El

bow

dia

gram

sho

uld

incl

ude

cart

ilage

, syn

ovia

l flu

id, j

oint

cap

sule

, nam

ed

bone

s an

d na

med

ant

agon

istic

mus

cles

.

• D

raw

ing

labe

lled

diag

ram

s of

the

stru

ctur

e of

a s

arco

mer

e sh

ould

incl

ude

Z lin

es, a

ctin

fila

men

ts, m

yosi

n fil

amen

ts w

ith h

eads

, and

the

resu

ltant

ligh

t an

d da

rk b

ands

.

• M

easu

rem

ent o

f the

leng

th o

f sar

com

eres

will

requ

ire c

alib

ratio

n of

the

eyep

iece

sca

le o

f the

mic

rosc

ope.


Biology guide104

Esse

ntia

l ide

a: A

ll an

imal

s ex

cret

e ni

trog

enou

s w

aste

pro

duct

s an

d so

me

anim

als

also

bal

ance

wat

er a

nd s

olut

e co

ncen

trat

ions

.

11.3

The

kid

ney

and

osm

oreg

ulat

ion

Nat

ure

of s

cien

ce:

Curio

sity

abo

ut p

artic

ular

phe

nom

ena—

inve

stig

atio

ns w

ere

carr

ied

out t

o de

term

ine

how

des

ert a

nim

als

prev

ent w

ater

loss

in th

eir w

aste

s. (1

.5)

Und

erst

andi

ngs:

• A

nim

als

are

eith

er o

smor

egul

ator

s or

osm

ocon

form

ers.

• Th

e M

alpi

ghia

n tu

bule

sys

tem

in in

sect

s an

d th

e ki

dney

car

ry o

ut

osm

oreg

ulat

ion

and

rem

oval

of n

itrog

enou

s w

aste

s.

• Th

e co

mpo

sitio

n of

blo

od in

the

rena

l art

ery

is d

iffer

ent f

rom

that

in th

e re

nal

vein

.

• Th

e ul

tras

truc

ture

of t

he g

lom

erul

us a

nd B

owm

an’s

caps

ule

faci

litat

e ul

traf

iltra

tion.

• Th

e pr

oxim

al c

onvo

lute

d tu

bule

sel

ectiv

ely

reab

sorb

s us

eful

sub

stan

ces

by

activ

e tr

ansp

ort.

• Th

e lo

op o

f Hen

le m

aint

ains

hyp

erto

nic

cond

ition

s in

the

med

ulla

.

• A

DH

con

trol

s re

abso

rptio

n of

wat

er in

the

colle

ctin

g du

ct.

• Th

e le

ngth

of t

he lo

op o

f Hen

le is

pos

itive

ly c

orre

late

d w

ith th

e ne

ed fo

r w

ater

con

serv

atio

n in

ani

mal

s.

• Th

e ty

pe o

f nitr

ogen

ous

was

te in

ani

mal

s is

cor

rela

ted

with

evo

lutio

nary

hi

stor

y an

d ha

bita

t.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: C

onse

quen

ces

of d

ehyd

ratio

n an

d ov

erhy

drat

ion.

• A

pplic

atio

n: T

reat

men

t of k

idne

y fa

ilure

by

hem

odia

lysi

s or

kid

ney

tran

spla

nt.

• A

pplic

atio

n: B

lood

cel

ls, g

luco

se, p

rote

ins

and

drug

s ar

e de

tect

ed in

urin

ary

test

s.

• Sk

ill: D

raw

ing

and

labe

lling

a d

iagr

am o

f the

hum

an k

idne

y.

• Sk

ill: A

nnot

atio

n of

dia

gram

s of

the

neph

ron.

Uti

lizat

ion:

• Th

e re

mov

al o

f kid

ney

ston

es b

y ul

tra

soun

d tr

eatm

ent.

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Bi

olog

yTo

pic

1.3

Mem

bran

e st

ruct

ure

Topi

c 1.

4 M

embr

ane

tran

spor

t


Biology guide 105

11.3

The

kid

ney

and

osm

oreg

ulat

ion

Gui

danc

e:

• A

DH

will

be

used

in p

refe

renc

e to

vas

opre

ssin

.

• Th

e di

agra

m o

f the

nep

hron

sho

uld

incl

ude

glom

erul

us, B

owm

an’s

caps

ule,

pr

oxim

al c

onvo

lute

d tu

bule

, loo

p of

Hen

le, d

ista

l con

volu

ted

tubu

le; t

he

rela

tions

hip

betw

een

the

neph

ron

and

the

colle

ctin

g du

ct s

houl

d be

in

clud

ed.


Biology guide106

Esse

ntia

l ide

a: S

exua

l rep

rodu

ctio

n in

volv

es th

e de

velo

pmen

t and

fusi

on o

f hap

loid

gam

etes

.

11.4

Sex

ual r

epro

duct

ion

Nat

ure

of s

cien

ce:

Ass

essi

ng ri

sks

and

bene

fits

asso

ciat

ed w

ith s

cien

tific

rese

arch

—th

e ris

ks to

hum

an m

ale

fert

ility

wer

e no

t ade

quat

ely

asse

ssed

bef

ore

ster

oids

rela

ted

to p

roge

ster

one

and

estr

ogen

wer

e re

leas

ed in

to th

e en

viro

nmen

t as

a re

sult

of th

e us

e of

the

fem

ale

cont

race

ptiv

e pi

ll. (4

.8)

Und

erst

andi

ngs:

• Sp

erm

atog

enes

is a

nd o

ogen

esis

bot

h in

volv

e m

itosi

s, c

ell g

row

th, t

wo

divi

sion

s of

mei

osis

and

di

ffer

entia

tion.

• Pr

oces

ses

in s

perm

atog

enes

is a

nd o

ogen

esis

resu

lt in

diff

eren

t num

bers

of g

amet

es w

ith d

iffer

ent a

mou

nts

of c

ytop

lasm

.

• Fe

rtili

zatio

n in

ani

mal

s ca

n be

inte

rnal

or e

xter

nal.

• Fe

rtili

zatio

n in

volv

es m

echa

nism

s th

at p

reve

nt p

olys

perm

y.

• Im

plan

tatio

n of

the

blas

tocy

st in

the

endo

met

rium

is e

ssen

tial f

or th

e co

ntin

uatio

n of

pre

gnan

cy.

• H

CG s

timul

ates

the

ovar

y to

sec

rete

pro

gest

eron

e du

ring

early

pre

gnan

cy.

• Th

e pl

acen

ta fa

cilit

ates

the

exch

ange

of m

ater

ials

bet

wee

n th

e m

othe

r and

fetu

s.

• Es

trog

en a

nd p

roge

ster

one

are

secr

eted

by

the

plac

enta

onc

e it

has

form

ed.

• Bi

rth

is m

edia

ted

by p

ositi

ve fe

edba

ck in

volv

ing

estr

ogen

and

oxy

toci

n.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: T

he a

vera

ge 3

8-w

eek

preg

nanc

y in

hum

ans

can

be p

ositi

oned

on

a gr

aph

show

ing

the

corr

elat

ion

betw

een

anim

al s

ize

and

the

deve

lopm

ent o

f the

you

ng a

t birt

h fo

r oth

er m

amm

als.

• Sk

ill: A

nnot

atio

n of

dia

gram

s of

sem

inife

rous

tubu

le a

nd o

vary

to s

how

the

stag

es o

f gam

etog

enes

is.

• Sk

ill: A

nnot

atio

n of

dia

gram

s of

mat

ure

sper

m a

nd e

gg to

indi

cate

func

tions

.

Gui

danc

e:

• Fe

rtili

zatio

n in

volv

es th

e ac

roso

me

reac

tion,

fusi

on o

f the

pla

sma

mem

bran

e of

the

egg

and

sper

m a

nd th

e co

rtic

al re

actio

n.

Uti

lizat

ion:

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Bi

olog

yTo

pic

3.3

Mei

osis

Topi

c 6.

6 H

orm

ones

, hom

eost

asis

and

repr

oduc

tion

Aim

s:

• A

im 8

: Dis

pute

s ov

er th

e re

spon

sibi

lity

for

froz

en h

uman

em

bryo

s.

107Biology guide 107

Opt

ion

A: N

euro

biol

ogy

and

beha

viou

r 15

/25

hour

s

Core

topi

cs

Esse

ntia

l ide

a: M

odifi

catio

n of

neu

rons

sta

rts

in th

e ea

rlies

t sta

ges

of e

mbr

yoge

nesi

s an

d co

ntin

ues

to th

e fin

al y

ears

of l

ife.

A.1

Neu

ral d

evel

opm

ent

Nat

ure

of s

cien

ce:

Use

mod

els

as re

pres

enta

tions

of t

he re

al w

orld

—de

velo

pmen

tal n

euro

scie

nce

uses

a v

arie

ty o

f ani

mal

mod

els.

(1.1

0)

Und

erst

andi

ngs:

• Th

e ne

ural

tube

of e

mbr

yoni

c ch

orda

tes

is fo

rmed

by

info

ldin

g of

ect

oder

m

follo

wed

by

elon

gatio

n of

the

tube

.

• N

euro

ns a

re in

itial

ly p

rodu

ced

by d

iffer

entia

tion

in th

e ne

ural

tube

.

• Im

mat

ure

neur

ons

mig

rate

to a

fina

l loc

atio

n.

• A

n ax

on g

row

s fr

om e

ach

imm

atur

e ne

uron

in re

spon

se to

che

mic

al s

timul

i.

• So

me

axon

s ex

tend

bey

ond

the

neur

al tu

be to

reac

h ot

her p

arts

of t

he b

ody.

• A

dev

elop

ing

neur

on fo

rms

mul

tiple

syn

apse

s.

• Sy

naps

es th

at a

re n

ot u

sed

do n

ot p

ersi

st.

• N

eura

l pru

ning

invo

lves

the

loss

of u

nuse

d ne

uron

s.

• Th

e pl

astic

ity o

f the

ner

vous

sys

tem

allo

ws

it to

cha

nge

with

exp

erie

nce.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: In

com

plet

e cl

osur

e of

the

embr

yoni

c ne

ural

tube

can

cau

se

spin

a bi

fida.

• A

pplic

atio

n: E

vent

s su

ch a

s st

roke

s m

ay p

rom

ote

reor

gani

zatio

n of

bra

in

func

tion.

• Sk

ill: A

nnot

atio

n of

a d

iagr

am o

f em

bryo

nic

tissu

es in

Xen

opus

, use

d as

an

anim

al m

odel

, dur

ing

neur

ulat

ion.

Inte

rnat

iona

l-m

inde

dnes

s:

• Cu

ltura

l exp

erie

nces

, inc

ludi

ng th

e ac

quis

ition

of a

lang

uage

, res

ults

in n

eura

l pr

unin

g.

Uti

lizat

ion:

• Re

sear

ch in

to th

e gr

owth

of n

erve

tiss

ue fo

r reg

ener

atio

n of

tiss

ue fo

r spi

nal

cord

inju

ry p

atie

nts

is p

rogr

essi

ng.

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Bi

olog

yTo

pic

6.5

Neu

rons

and

syn

apse

s

Core topics

Biology guide108

A.1

Neu

ral d

evel

opm

ent

Gui

danc

e:

• Te

rmin

olog

y re

latin

g to

em

bryo

nic

brai

n ar

eas

or n

ervo

us s

yste

m d

ivis

ions

is

not r

equi

red.

Core topics

Biology guide 109

Esse

ntia

l ide

a: T

he p

arts

of t

he b

rain

spe

cial

ize

in d

iffer

ent f

unct

ions

.

A.2

The

hum

an b

rain

Nat

ure

of s

cien

ce:

Use

mod

els

as re

pres

enta

tions

of t

he re

al w

orld

—th

e se

nsor

y ho

mun

culu

s an

d m

otor

hom

uncu

lus

are

mod

els

of th

e re

lativ

e sp

ace

hum

an b

ody

part

s oc

cupy

on

the

som

atos

enso

ry c

orte

x an

d th

e m

otor

cor

tex.

(1.1

0)

Und

erst

andi

ngs:

• Th

e an

terio

r par

t of t

he n

eura

l tub

e ex

pand

s to

form

the

brai

n.

• D

iffer

ent p

arts

of t

he b

rain

hav

e sp

ecifi

c ro

les.

• Th

e au

tono

mic

ner

vous

sys

tem

con

trol

s in

volu

ntar

y pr

oces

ses

in th

e bo

dy

usin

g ce

ntre

s lo

cate

d m

ainl

y in

the

brai

n st

em.

• Th

e ce

rebr

al c

orte

x fo

rms

a la

rger

pro

port

ion

of th

e br

ain

and

is m

ore

high

ly

deve

lope

d in

hum

ans

than

oth

er a

nim

als.

• Th

e hu

man

cer

ebra

l cor

tex

has

beco

me

enla

rged

prin

cipa

lly b

y an

incr

ease

in

tota

l are

a w

ith e

xten

sive

fold

ing

to a

ccom

mod

ate

it w

ithin

the

cran

ium

.

• Th

e ce

rebr

al h

emis

pher

es a

re re

spon

sibl

e fo

r hig

her o

rder

func

tions

.

• Th

e le

ft c

ereb

ral h

emis

pher

e re

ceiv

es s

enso

ry in

put f

rom

sen

sory

rece

ptor

s in

the

right

sid

e of

the

body

and

the

right

sid

e of

the

visu

al fi

eld

in b

oth

eyes

an

d vi

ce v

ersa

for t

he ri

ght h

emis

pher

e.

• Th

e le

ft c

ereb

ral h

emis

pher

e co

ntro

ls m

uscl

e co

ntra

ctio

n in

the

right

sid

e of

th

e bo

dy a

nd v

ice

vers

a fo

r the

righ

t hem

isph

ere.

• Br

ain

met

abol

ism

requ

ires

larg

e en

ergy

inpu

ts.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: V

isua

l cor

tex,

Bro

ca’s

area

, nuc

leus

acc

umbe

ns a

s ar

eas

of th

e br

ain

with

spe

cific

func

tions

.

• A

pplic

atio

n: S

wal

low

ing,

bre

athi

ng a

nd h

eart

rate

as

exam

ples

of a

ctiv

ities

co

ordi

nate

d by

the

med

ulla

.

Inte

rnat

iona

l-m

inde

dnes

s:

• Th

e de

finiti

on o

f liv

ing

varie

s de

pend

ing

on lo

cal a

nd n

atio

nal l

aws

and

cultu

re.

Theo

ry o

f kno

wle

dge:

• In

med

icin

e th

e co

ncep

t of d

eath

is d

efin

ed in

term

s of

bra

in fu

nctio

n, b

ut

som

etim

es c

onfli

cts

can

occu

r whe

n th

e m

edic

al c

riter

ia fo

r dea

th d

iffer

from

th

e fa

mily

’s cr

iteria

for d

eath

. To

wha

t ext

ent s

houl

d th

e vi

ews

of th

e fa

mily

m

embe

rs b

e gi

ven

prio

rity

whe

n m

akin

g de

cisi

ons

in m

edic

al e

thic

s? W

hat

crite

ria s

houl

d be

use

d to

mak

e et

hica

l dec

isio

ns?

Uti

lizat

ion:

• A

ngel

man

syn

drom

e is

a g

enet

ical

ly in

herit

ed c

ondi

tion

that

is d

iagn

osed

fr

om c

hara

cter

istic

ally

abn

orm

al p

atte

rns

on a

n el

ectr

oenc

epha

logr

am.

Core topics

Biology guide110

A.2

The

hum

an b

rain

• A

pplic

atio

n: U

se o

f the

pup

il re

flex

to e

valu

ate

brai

n da

mag

e.

• A

pplic

atio

n: U

se o

f ani

mal

exp

erim

ents

, aut

opsy

, les

ions

and

fMRI

to id

entif

y th

e ro

le o

f diff

eren

t bra

in p

arts

.

• Sk

ill: I

dent

ifica

tion

of p

arts

of t

he b

rain

in a

pho

togr

aph,

dia

gram

or s

can

of

the

brai

n.

• Sk

ill: A

naly

sis

of c

orre

latio

ns b

etw

een

body

siz

e an

d br

ain

size

in d

iffer

ent

anim

als.

Gui

danc

e:

• Im

age

of th

e br

ain

shou

ld in

clud

e th

e m

edul

la o

blon

gata

, cer

ebel

lum

, hy

poth

alam

us, p

ituita

ry g

land

and

cer

ebra

l hem

isph

eres

.

• A

lthou

gh s

peci

fic fu

nctio

ns c

an b

e at

trib

uted

to c

erta

in a

reas

, bra

in im

ager

y sh

ows

that

som

e ac

tiviti

es a

re s

prea

d in

man

y ar

eas

and

that

the

brai

n ca

n ev

en re

orga

nize

itse

lf fo

llow

ing

a di

stur

banc

e su

ch a

s a

stro

ke.

Core topics

Biology guide 111

Esse

ntia

l ide

a: L

ivin

g or

gani

sms

are

able

to d

etec

t cha

nges

in th

e en

viro

nmen

t.

A.3

Per

cept

ion

of s

tim

uli

Nat

ure

of s

cien

ce:

Und

erst

andi

ng o

f the

und

erly

ing

scie

nce

is th

e ba

sis

for t

echn

olog

ical

dev

elop

men

ts—

the

disc

over

y th

at e

lect

rical

stim

ulat

ion

in th

e au

dito

ry s

yste

m c

an c

reat

e a

perc

eptio

n of

sou

nd re

sulte

d in

the

deve

lopm

ent o

f ele

ctric

al h

earin

g ai

ds a

nd u

ltim

atel

y co

chle

ar im

plan

ts. (

1.2)

Und

erst

andi

ngs:

• Re

cept

ors

dete

ct c

hang

es in

the

envi

ronm

ent.

• Ro

ds a

nd c

ones

are

pho

tore

cept

ors

loca

ted

in th

e re

tina.

• Ro

ds a

nd c

ones

diff

er in

thei

r sen

sitiv

ities

to li

ght i

nten

sitie

s an

d w

avel

engt

hs.

• Bi

pola

r cel

ls s

end

the

impu

lses

from

rods

and

con

es to

gan

glio

n ce

lls.

• G

angl

ion

cells

sen

d m

essa

ges

to th

e br

ain

via

the

optic

ner

ve.

• Th

e in

form

atio

n fr

om th

e rig

ht fi

eld

of v

isio

n fr

om b

oth

eyes

is s

ent t

o th

e le

ft

part

of t

he v

isua

l cor

tex

and

vice

ver

sa.

• St

ruct

ures

in th

e m

iddl

e ea

r tra

nsm

it an

d am

plify

sou

nd.

• Se

nsor

y ha

irs o

f the

coc

hlea

det

ect s

ound

s of

spe

cific

freq

uenc

y.

• Im

puls

es c

ause

d by

sou

nd p

erce

ptio

n ar

e tr

ansm

itted

to th

e br

ain

via

the

audi

tory

ner

ve.

• H

air c

ells

in th

e se

mic

ircul

ar c

anal

s de

tect

mov

emen

t of t

he h

ead.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: R

ed-g

reen

col

our-

blin

dnes

s as

a v

aria

nt o

f nor

mal

tric

hrom

atic

vi

sion

.

• A

pplic

atio

n: D

etec

tion

of c

hem

ical

s in

the

air b

y th

e m

any

diff

eren

t olfa

ctor

y re

cept

ors.

• A

pplic

atio

n: U

se o

f coc

hlea

r im

plan

ts in

dea

f pat

ient

s.

• Sk

ill: L

abel

ling

a di

agra

m o

f the

str

uctu

re o

f the

hum

an e

ye.

• Th

eory

of k

now

ledg

e:

Oth

er o

rgan

ism

s ca

n de

tect

stim

uli t

hat h

uman

s ca

nnot

. For

exa

mpl

e, s

ome

polli

nato

rs c

an d

etec

t ele

ctro

mag

netic

radi

atio

n in

the

non-

visi

ble

rang

e. A

s a

cons

eque

nce,

they

mig

ht p

erce

ive

a flo

wer

as

patt

erne

d w

hen

we

perc

eive

it

as p

lain

. To

wha

t ext

ent,

ther

efor

e, is

wha

t we

perc

eive

mer

ely

an in

divi

dual

co

nstr

uctio

n of

real

ity?

Uti

lizat

ion:

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Bi

olog

yTo

pic

3.4

Inhe

ritan

cePh

ysic

sTo

pic

4.2

Trav

ellin

g w

aves

Core topics

Biology guide112

A.3

Per

cept

ion

of s

tim

uli

• Sk

ill: A

nnot

atio

n of

a d

iagr

am o

f the

retin

a to

sho

w th

e ce

ll ty

pes

and

the

dire

ctio

n in

whi

ch li

ght m

oves

.

• Sk

ill: L

abel

ling

a di

agra

m o

f the

str

uctu

re o

f the

hum

an e

ar.

Gui

danc

e:

• H

uman

s’ s

enso

ry re

cept

ors

shou

ld in

clud

e m

echa

nore

cept

ors,

ch

emor

ecep

tors

, the

rmor

ecep

tors

and

pho

tore

cept

ors.

• D

iagr

am o

f hum

an e

ye s

houl

d in

clud

e th

e sc

lera

, cor

nea,

con

junc

tiva,

eye

lid,

chor

oid,

aqu

eous

hum

our,

pupi

l, le

ns, i

ris, v

itreo

us h

umou

r, re

tina,

fove

a,

optic

ner

ve a

nd b

lind

spot

.

• D

iagr

am o

f ret

ina

shou

ld in

clud

e ro

d an

d co

ne c

ells

, bip

olar

neu

rons

and

ga

nglio

n ce

lls.

• D

iagr

am o

f ear

sho

uld

incl

ude

pinn

a, e

ardr

um, b

ones

of t

he m

iddl

e ea

r, ov

al

win

dow

, rou

nd w

indo

w, s

emic

ircul

ar c

anal

s, a

udito

ry n

erve

and

coc

hlea

.


Opt

ion

A: N

euro

biol

ogy

and

beha

viou

r 15

/25

hour

s

Addi

tiona

l hig

her l

evel

topi

cs

Esse

ntia

l ide

a: B

ehav

iour

al p

atte

rns

can

be in

herit

ed o

r lea

rned

.

A.4

Inna

te a

nd le

arne

d be

havi

our

Nat

ure

of s

cien

ce:

Look

ing

for p

atte

rns,

tren

ds a

nd d

iscr

epan

cies

—la

bora

tory

exp

erim

ents

and

fiel

d in

vest

igat

ions

hel

ped

in th

e un

ders

tand

ing

of d

iffer

ent t

ypes

of b

ehav

iour

and

le

arni

ng. (

3.1)

Und

erst

andi

ngs:

• In

nate

beh

avio

ur is

inhe

rited

from

par

ents

and

so

deve

lops

inde

pend

ently

of

the

envi

ronm

ent.

• Au

tono

mic

and

invo

lunt

ary

resp

onse

s ar

e re

ferr

ed to

as

refle

xes.

• Re

flex

arcs

com

pris

e th

e ne

uron

s th

at m

edia

te re

flexe

s.

• Re

flex

cond

ition

ing

invo

lves

form

ing

new

ass

ocia

tions

.

• Le

arne

d be

havi

our d

evel

ops

as a

resu

lt of

exp

erie

nce.

• Im

prin

ting

is le

arni

ng o

ccur

ring

at a

par

ticul

ar li

fe s

tage

and

is in

depe

nden

t of

the

cons

eque

nces

of b

ehav

iour

.

• O

pera

nt c

ondi

tioni

ng is

a fo

rm o

f lea

rnin

g th

at c

onsi

sts

of tr

ial a

nd e

rror

ex

perie

nces

.

• Le

arni

ng is

the

acqu

isiti

on o

f ski

ll or

kno

wle

dge.

• M

emor

y is

the

proc

ess

of e

ncod

ing,

sto

ring

and

acce

ssin

g in

form

atio

n.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: W

ithdr

awal

refle

x of

the

hand

from

a p

ainf

ul s

timul

us.

• A

pplic

atio

n: P

avlo

v’s

expe

rimen

ts in

to re

flex

cond

ition

ing

in d

ogs.

Theo

ry o

f kno

wle

dge:

• It

is e

asy

for u

s to

gue

ss h

ow th

e be

havi

our o

f an

anim

al m

ight

influ

ence

its

chan

ce o

f sur

viva

l and

repr

oduc

tion.

Is in

tuiti

on a

val

id s

tart

ing

poin

t for

sc

ient

ists

?

Aim

s:

• A

im 7

: Dat

a lo

ggin

g us

ing

an e

lect

roca

rdio

gram

(ECG

) sen

sor t

o an

alys

e ne

urom

uscu

lar r

efle

xes.

• A

im 8

: Exp

erim

ents

with

ani

mal

s—im

plic

atio

ns o

f tod

ay’s

anim

al p

olic

ies

for

expe

rimen

tal s

cien

ce in

Pav

lov’

s ex

perim

ents

.


Biology guide114

A.4

Inna

te a

nd le

arne

d be

havi

our

• A

pplic

atio

n: T

he ro

le o

f inh

erita

nce

and

lear

ning

in th

e de

velo

pmen

t of

bird

song

.

• Sk

ill: A

naly

sis

of d

ata

from

inve

rteb

rate

beh

avio

ur e

xper

imen

ts in

term

s of

th

e ef

fect

on

chan

ces

of s

urvi

val a

nd re

prod

uctio

n.

• Sk

ill: D

raw

ing

and

labe

lling

a d

iagr

am o

f a re

flex

arc

for a

pai

n w

ithdr

awal

re

flex.

Gui

danc

e:

• D

raw

ing

of re

flex

arc

shou

ld in

clud

e th

e re

cept

or c

ell,

sens

ory

neur

on, r

elay

ne

uron

, mot

or n

euro

n an

d ef

fect

or.


Biology guide 115

Esse

ntia

l ide

a: C

omm

unic

atio

n be

twee

n ne

uron

s ca

n be

alte

red

thro

ugh

the

man

ipul

atio

n of

the

rele

ase

and

rece

ptio

n of

che

mic

al m

esse

nger

s.

A.5

Neu

roph

arm

acol

ogy

Nat

ure

of s

cien

ce:

Ass

essi

ng ri

sks

asso

ciat

ed w

ith s

cien

tific

rese

arch

—pa

tient

adv

ocat

es w

ill o

ften

pre

ss fo

r the

spe

edin

g up

of d

rug

appr

oval

pro

cess

es, e

ncou

ragi

ng m

ore

tole

ranc

e of

ris

k. (4

.5)

Und

erst

andi

ngs:

• So

me

neur

otra

nsm

itter

s ex

cite

ner

ve im

puls

es in

pos

tsyn

aptic

neu

rons

and

ot

hers

inhi

bit t

hem

.

• N

erve

impu

lses

are

initi

ated

or i

nhib

ited

in p

ost-

syna

ptic

neu

rons

as

a re

sult

of s

umm

atio

n of

all

exci

tato

ry a

nd in

hibi

tory

neu

rotr

ansm

itter

s re

ceiv

ed fr

om

pres

ynap

tic n

euro

ns.

• M

any

diff

eren

t slo

w-a

ctin

g ne

urot

rans

mitt

ers

mod

ulat

e fa

st s

ynap

tic

tran

smis

sion

in th

e br

ain.

• M

emor

y an

d le

arni

ng in

volv

e ch

ange

s in

neu

rons

cau

sed

by s

low

-act

ing

neur

otra

nsm

itter

s.

• Ps

ycho

activ

e dr

ugs

affe

ct th

e br

ain

by e

ither

incr

easi

ng o

r dec

reas

ing

post

syna

ptic

tran

smis

sion

.

• A

nest

hetic

s ac

t by

inte

rfer

ing

with

neu

ral t

rans

mis

sion

bet

wee

n ar

eas

of

sens

ory

perc

eptio

n an

d th

e CN

S.

• St

imul

ant d

rugs

mim

ic th

e st

imul

atio

n pr

ovid

ed b

y th

e sy

mpa

thet

ic n

ervo

us

syst

em.

• A

ddic

tion

can

be a

ffec

ted

by g

enet

ic p

redi

spos

ition

, soc

ial e

nviro

nmen

t and

do

pam

ine

secr

etio

n.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: E

ffec

ts o

n th

e ne

rvou

s sy

stem

of t

wo

stim

ulan

ts a

nd tw

o se

dativ

es.

• A

pplic

atio

n: T

he e

ffec

t of a

nest

hetic

s on

aw

aren

ess.

Inte

rnat

iona

l-m

inde

dnes

s:

• At

titud

es to

dru

gs a

nd th

e us

e of

dru

gs d

iffer

glo

bally

. The

re a

re m

any

cultu

res

that

use

dru

gs to

enh

ance

ritu

als

or re

ligio

us e

xper

ienc

es.

Uti

lizat

ion:

• M

any

psyc

hoac

tive

drug

s ha

ve b

een

used

ther

apeu

tical

ly to

trea

t a ra

nge

of

men

tal i

llnes

ses

and

psyc

holo

gica

l dis

orde

rs.

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Ch

emis

try

Opt

ion

D M

edic

inal

che

mis

try

Topi

c D

1 Ph

arm

aceu

tical

pro

duct

s an

d dr

ug a

ctio

nTo

pic

D3

Opi

ates

Psyc

holo

gyCo

re: B

iolo

gica

l lev

el o

f ana

lysi

s

Aim

s:

• A

im 8

: The

soc

ial c

onse

quen

ces

of p

sych

oact

ive

drug

s co

uld

be c

onsi

dere

d,

for t

he u

ser,

his

or h

er fa

mily

and

the

wid

er s

ocie

ty.


Biology guide116

A.5

Neu

roph

arm

acol

ogy

• A

pplic

atio

n: E

ndor

phin

s ca

n ac

t as

pain

kille

rs.

• Sk

ill: E

valu

atio

n of

dat

a sh

owin

g th

e im

pact

of M

DM

A (e

csta

sy) o

n se

roto

nin

and

dopa

min

e m

etab

olis

m in

the

brai

n.

Gui

danc

e:

• Ex

ampl

es o

f stim

ulan

ts a

re n

icot

ine,

coc

aine

or a

mph

etam

ines

.

• Ex

ampl

es o

f sed

ativ

es a

re b

enzo

diaz

epin

es, a

lcoh

ol o

r tet

rahy

droc

anna

bino

l (T

HC)

.


Biology guide 117

Esse

ntia

l ide

a: N

atur

al s

elec

tion

favo

urs

spec

ific

type

s of

beh

avio

ur.

A.6

Eth

olog

y

Nat

ure

of s

cien

ce:

Test

ing

a hy

poth

esis

—ex

perim

ents

to te

st h

ypot

hese

s on

the

mig

rato

ry b

ehav

iour

of b

lack

caps

hav

e be

en c

arrie

d ou

t. (1

.9)

Und

erst

andi

ngs:

• Et

holo

gy is

the

stud

y of

ani

mal

beh

avio

ur in

nat

ural

con

ditio

ns.

• N

atur

al s

elec

tion

can

chan

ge th

e fr

eque

ncy

of o

bser

ved

anim

al b

ehav

iour

.

• Be

havi

our t

hat i

ncre

ases

the

chan

ces

of s

urvi

val a

nd re

prod

uctio

n w

ill

beco

me

mor

e pr

eval

ent i

n a

popu

latio

n.

• Le

arne

d be

havi

our c

an s

prea

d th

roug

h a

popu

latio

n or

be

lost

from

it m

ore

rapi

dly

than

inna

te b

ehav

iour

.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: M

igra

tory

beh

avio

ur in

bla

ckca

ps a

s an

exa

mpl

e of

the

gene

tic

basi

s of

beh

avio

ur a

nd it

s ch

ange

by

natu

ral s

elec

tion.

• A

pplic

atio

n: B

lood

sha

ring

in v

ampi

re b

ats

as a

n ex

ampl

e of

the

deve

lopm

ent

of a

ltrui

stic

beh

avio

ur b

y na

tura

l sel

ectio

n.

• A

pplic

atio

n: F

orag

ing

beha

viou

r in

shor

e cr

abs

as a

n ex

ampl

e of

incr

easi

ng

chan

ces

of s

urvi

val b

y op

timal

pre

y ch

oice

.

• A

pplic

atio

n: B

reed

ing

stra

tegi

es in

coh

o sa

lmon

pop

ulat

ions

as

an e

xam

ple

of b

ehav

iour

aff

ectin

g ch

ance

s of

sur

viva

l and

repr

oduc

tion.

• A

pplic

atio

n: C

ourt

ship

in b

irds

of p

arad

ise

as a

n ex

ampl

e of

mat

e se

lect

ion.

• A

pplic

atio

n: S

ynch

roni

zed

oest

rus

in fe

mal

e lio

ns in

a p

ride

as a

n ex

ampl

e of

in

nate

beh

avio

ur th

at in

crea

ses

the

chan

ces

of s

urvi

val a

nd re

prod

uctio

n of

of

fspr

ing.

• A

pplic

atio

n: F

eedi

ng o

n cr

eam

from

milk

bot

tles

in b

lue

tits

as a

n ex

ampl

e of

th

e de

velo

pmen

t and

loss

of l

earn

ed b

ehav

iour

.

Theo

ry o

f kno

wle

dge:

• Th

e “J

ust S

o” s

torie

s by

Rud

yard

Kip

ling

are

liter

ary

expl

anat

ions

of a

nim

al

beha

viou

r. W

hat a

re th

e fe

atur

es o

f a s

cien

tific

exp

lana

tion

rath

er th

an a

hi

stor

ical

or l

itera

ry e

xpla

natio

n?

Uti

lizat

ions

:

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Bi

olog

yTo

pic

5.2

Nat

ural

sel

ectio

n


Biology guide118

A.6

Eth

olog

y

Gui

danc

e:

• Th

e se

ven

appl

icat

ions

in th

is s

ub-t

opic

are

inte

nded

to re

info

rce

unde

rsta

ndin

g of

the

gene

ral p

rinci

ples

. The

app

licat

ions

incl

ude

a ra

nge

of ty

pes

of b

ehav

iour

and

type

s of

ani

mal

. Oth

er e

xam

ples

, inc

ludi

ng lo

cal

exam

ples

that

can

be

obse

rved

, sho

uld

also

be

stud

ied

if po

ssib

le.


Opt

ion

B: B

iote

chno

logy

and

bio

info

rmat

ics

15/2

5 ho

urs

Core

topi

cs

Esse

ntia

l ide

a: M

icro

orga

nism

s ca

n be

use

d an

d m

odifi

ed to

per

form

indu

stria

l pro

cess

es.

B.1

Mic

robi

olog

y: o

rgan

ism

s in

indu

stry

Nat

ure

of s

cien

ce:

Sere

ndip

ity h

as le

d to

sci

entif

ic d

isco

verie

s—th

e di

scov

ery

of p

enic

illin

by

Ale

xand

er F

lem

ing

coul

d be

vie

wed

as

a ch

ance

occ

urre

nce.

(1.4

)

Und

erst

andi

ngs:

• M

icro

orga

nism

s ar

e m

etab

olic

ally

div

erse

.

• M

icro

orga

nism

s ar

e us

ed in

indu

stry

bec

ause

they

are

sm

all a

nd h

ave

a fa

st

grow

th ra

te.

• Pa

thw

ay e

ngin

eerin

g op

timiz

es g

enet

ic a

nd re

gula

tory

pro

cess

es w

ithin

m

icro

orga

nism

s.

• Pa

thw

ay e

ngin

eerin

g is

use

d in

dust

rially

to p

rodu

ce m

etab

olite

s of

inte

rest

.

• Fe

rmen

ters

allo

w la

rge-

scal

e pr

oduc

tion

of m

etab

olite

s by

mic

roor

gani

sms.

• Fe

rmen

tatio

n is

car

ried

out b

y ba

tch

or c

ontin

uous

cul

ture

.

• M

icro

orga

nism

s in

ferm

ente

rs b

ecom

e lim

ited

by th

eir o

wn

was

te p

rodu

cts.

• Pr

obes

are

use

d to

mon

itor c

ondi

tions

with

in fe

rmen

ters

.

• Co

nditi

ons

are

mai

ntai

ned

at o

ptim

al le

vels

for t

he g

row

th o

f the

m

icro

orga

nism

s be

ing

cultu

red.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: D

eep-

tank

bat

ch fe

rmen

tatio

n in

the

mas

s pr

oduc

tion

of

peni

cilli

n.

• A

pplic

atio

n: P

rodu

ctio

n of

citr

ic a

cid

in a

con

tinuo

us fe

rmen

ter b

y As

perg

illus

ni

ger a

nd it

s us

e as

a p

rese

rvat

ive

and

flavo

urin

g.

Theo

ry o

f kno

wle

dge:

• A

lexa

nder

Fle

min

g di

scov

ered

pen

icill

in in

Eng

land

in 1

928,

on

a di

scar

ded

petr

i dis

h. T

o w

hat e

xten

t was

Dr F

lem

ing’

s di

scov

ery

a lu

cky

obse

rvat

ion,

or

do w

e on

ly p

erce

ive

wha

t we

are

open

to?

Uti

lizat

ion:

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Bi

olog

yTo

pic

2.1

Mol

ecul

es to

met

abol

ism

Topi

c 4.

3 Ca

rbon

cyc

ling

Topi

c 6.

3 D

efen

ce a

gain

st in

fect

ious

dis

ease

Core topics

Biology guide120

B.1

Mic

robi

olog

y: o

rgan

ism

s in

indu

stry

• A

pplic

atio

n: B

ioga

s is

pro

duce

d by

bac

teria

and

arc

haea

ns fr

om o

rgan

ic

mat

ter i

n fe

rmen

ters

.

• Sk

ill: G

ram

sta

inin

g of

Gra

m-p

ositi

ve a

nd G

ram

-neg

ativ

e ba

cter

ia.

• Sk

ill: E

xper

imen

ts s

how

ing

zone

of i

nhib

ition

of b

acte

rial g

row

th b

y ba

cter

icid

es in

ste

rile

bact

eria

l cul

ture

s.

• Sk

ill: P

rodu

ctio

n of

bio

gas

in a

sm

all-s

cale

ferm

ente

r.

Core topics

Biology guide 121

Esse

ntia

l ide

a: C

rops

can

be

mod

ified

to in

crea

se y

ield

s an

d to

obt

ain

nove

l pro

duct

s.

B.2

Biot

echn

olog

y in

agr

icul

ture

Nat

ure

of s

cien

ce:

Ass

essin

g ris

ks a

nd b

enef

its a

ssoc

iate

d w

ith sc

ient

ific

rese

arch

—sc

ient

ists n

eed

to e

valu

ate

the

pote

ntia

l of h

erbi

cide

resis

tanc

e ge

nes e

scap

ing

into

the

wild

pop

ulat

ion.

(4.8

)

Und

erst

andi

ngs:

• Tr

ansg

enic

org

anis

ms

prod

uce

prot

eins

that

wer

e no

t pre

viou

sly

part

of t

heir

spec

ies’

pro

teom

e.

• G

enet

ic m

odifi

catio

n ca

n be

use

d to

ove

rcom

e en

viro

nmen

tal r

esis

tanc

e to

in

crea

se c

rop

yiel

ds.

• G

enet

ical

ly m

odifi

ed c

rop

plan

ts c

an b

e us

ed to

pro

duce

nov

el p

rodu

cts.

• Bi

oinf

orm

atic

s pl

ays

a ro

le in

iden

tifyi

ng ta

rget

gen

es.

• Th

e ta

rget

gen

e is

link

ed to

oth

er s

eque

nces

that

con

trol

its

expr

essi

on.

• A

n op

en re

adin

g fr

ame

is a

sig

nific

ant l

engt

h of

DN

A fr

om a

sta

rt c

odon

to a

st

op c

odon

.

• M

arke

r gen

es a

re u

sed

to in

dica

te s

ucce

ssfu

l upt

ake.

• Re

com

bina

nt D

NA

mus

t be

inse

rted

into

the

plan

t cel

l and

take

n up

by

its

chro

mos

ome

or c

hlor

opla

st D

NA

.

• Re

com

bina

nt D

NA

can

be

intr

oduc

ed in

to w

hole

pla

nts,

leaf

dis

cs o

r pr

otop

last

s.

• Re

com

bina

nt D

NA

can

be

intr

oduc

ed b

y di

rect

phy

sica

l and

che

mic

al

met

hods

or i

ndire

ctly

by

vect

ors.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: U

se o

f tum

our-

indu

cing

(Ti)

plas

mid

of A

grob

acte

rium

tu

mef

acie

ns to

intr

oduc

e gl

ypho

sate

resi

stan

ce in

to s

oybe

an c

rops

.

• A

pplic

atio

n: G

enet

ic m

odifi

catio

n of

toba

cco

mos

aic

viru

s to

allo

w b

ulk

prod

uctio

n of

Hep

atiti

s B

vacc

ine

in to

bacc

o pl

ants

.

Uti

lizat

ion:

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Bi

olog

yTo

pic

1.5

The

orig

in o

f cel

ls

Topi

c 3.

5 G

enet

ic m

odifi

catio

n an

d bi

otec

hnol

ogy

Envi

ronm

enta

l sys

tem

s an

d so

ciet

ies

Topi

c 5.

2 Te

rres

tria

l foo

d pr

oduc

tion

syst

ems

Aim

s:

• A

im 7

: Use

of b

ioin

form

atic

s to

det

erm

ine

sequ

ence

s to

be

mod

ified

.

• A

im 8

: The

re a

re e

thic

al a

nd p

oliti

cal i

mpl

icat

ions

in th

e in

trod

uctio

n of

the

gene

tical

ly m

odifi

ed p

otat

o A

mflo

ra in

Eur

ope.

Core topics

Biology guide122

B.2

Biot

echn

olog

y in

agr

icul

ture

• A

pplic

atio

n: P

rodu

ctio

n of

Am

flora

pot

ato

(Sol

anum

tube

rosu

m) f

or p

aper

an

d ad

hesi

ve in

dust

ries.

• Sk

ill: E

valu

atio

n of

dat

a on

the

envi

ronm

enta

l im

pact

of g

lyph

osat

e-to

lera

nt

soyb

eans

.

• Sk

ill: I

dent

ifica

tion

of a

n op

en re

adin

g fr

ame

(ORF

).

Gui

danc

e:

• A

sig

nific

ant l

engt

h of

DN

A fo

r an

open

read

ing

fram

e co

ntai

ns s

uffic

ient

nu

cleo

tides

to c

ode

for a

pol

ypep

tide

chai

n.

• Li

mit

the

chem

ical

met

hods

of i

ntro

duci

ng g

enes

into

pla

nts

to c

alci

um

chlo

ride

and

lipos

omes

.

• Li

mit

the

phys

ical

met

hods

of i

ntro

duci

ng g

enes

into

pla

nts

to

elec

trop

orat

ion,

mic

roin

ject

ion

and

biol

istic

s (g

unsh

ot).

• Li

mit

vect

ors

to A

grob

acte

rium

tum

efac

iens

and

toba

cco

mos

aic

viru

s.

Core topics

Biology guide 123

Esse

ntia

l ide

a: B

iote

chno

logy

can

be

used

in th

e pr

even

tion

and

miti

gatio

n of

con

tam

inat

ion

from

indu

stria

l, ag

ricul

tura

l and

mun

icip

al w

aste

s.

B.3

Envi

ronm

enta

l pro

tect

ion

Nat

ure

of s

cien

ce:

Dev

elop

men

ts in

sci

entif

ic re

sear

ch fo

llow

impr

ovem

ents

in a

ppar

atus

—us

ing

tool

s su

ch a

s th

e la

ser s

cann

ing

mic

rosc

ope

has

led

rese

arch

ers

to d

eepe

r und

erst

andi

ng

of th

e st

ruct

ure

of b

iofil

ms.

(1.8

)

Und

erst

andi

ngs:

• Re

spon

ses

to p

ollu

tion

inci

dent

s ca

n in

volv

e bi

orem

edia

tion

com

bine

d w

ith

phys

ical

and

che

mic

al p

roce

dure

s.

• M

icro

orga

nism

s ar

e us

ed in

bio

rem

edia

tion.

• So

me

pollu

tant

s ar

e m

etab

oliz

ed b

y m

icro

orga

nism

s.

• Co

oper

ativ

e ag

greg

ates

of m

icro

orga

nism

s ca

n fo

rm b

iofil

ms.

• Bi

ofilm

s po

sses

s em

erge

nt p

rope

rtie

s.

• M

icro

orga

nism

s gro

win

g in

a b

iofil

m a

re h

ighl

y re

sista

nt to

ant

imic

robi

al a

gent

s.

• M

icro

orga

nism

s in

bio

film

s co

oper

ate

thro

ugh

quor

um s

ensi

ng.

• Ba

cter

ioph

ages

are

use

d in

the

disi

nfec

tion

of w

ater

sys

tem

s.

App

licat

ions

and

ski

lls:

• Ap

plic

atio

n: D

egra

datio

n of

ben

zene

by

halo

phili

c ba

cter

ia su

ch a

s Mar

inob

acte

r.

• A

pplic

atio

n: D

egra

datio

n of

oil

by P

seud

omon

as.

• A

pplic

atio

n: C

onve

rsio

n by

Pse

udom

onas

of m

ethy

l mer

cury

into

ele

men

tal

mer

cury

.

• A

pplic

atio

n: U

se o

f bio

film

s in

tric

kle

filte

r bed

s fo

r sew

age

trea

tmen

t.

• Sk

ill: E

valu

atio

n of

dat

a or

med

ia re

port

s on

env

ironm

enta

l pro

blem

s ca

used

by

bio

film

s.

Gui

danc

e:

• Ex

ampl

es o

f env

ironm

enta

l pro

blem

s ca

used

by

biof

ilms

coul

d in

clud

e cl

oggi

ng a

nd c

orro

sion

of p

ipes

, tra

nsfe

r of m

icro

orga

nism

s in

bal

last

wat

er

or c

onta

min

atio

n of

sur

face

s in

food

pro

duct

ion.

Inte

rnat

iona

l-m

inde

dnes

s:

• D

urin

g oi

l spi

lls s

cien

tists

from

diff

eren

t par

ts o

f the

wor

ld w

ork

toge

ther

to

prot

ect t

he e

nviro

nmen

t.

Theo

ry o

f kno

wle

dge:

• Em

erge

nt p

rope

rtie

s ar

e th

e ou

tcom

e of

the

inte

ract

ion

of th

e el

emen

ts o

f a

syst

em. I

n w

hat c

onte

xt is

a re

duct

ioni

st a

ppro

ach

to s

cien

ce p

rodu

ctiv

e an

d in

wha

t con

text

is a

redu

ctio

nist

app

roac

h pr

oble

mat

ic?

Uti

lizat

ion:

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Bi

olog

yTo

pic

1 Ce

ll bi

olog

yCh

emis

try

Opt

ion

C2 F

ossi

l fue

lsEn

viro

nmen

tal s

yste

ms

and

soci

etie

s To

pic

4.4

Wat

er p

ollu

tion

Topi

c 6.

3 Ph

otoc

hem

ical

sm

ogTo

pic

6.4

Aci

d de

posi

tion

Biology guide124

Opt

ion

B: B

iote

chno

logy

and

bio

info

rmat

ics

15/2

5 ho

urs

Addi

tiona

l hig

her l

evel

topi

cs

Esse

ntia

l ide

a: B

iote

chno

logy

can

be

used

in th

e di

agno

sis

and

trea

tmen

t of d

isea

se.

B.4

Med

icin

e

Nat

ure

of s

cien

ce:

Dev

elop

men

ts in

sci

entif

ic re

sear

ch fo

llow

impr

ovem

ents

in te

chno

logy

—in

nova

tion

in te

chno

logy

has

allo

wed

sci

entis

ts to

dia

gnos

e an

d tr

eat d

isea

ses.

(1.8

)

Und

erst

andi

ngs:

• In

fect

ion

by a

pat

hoge

n ca

n be

det

ecte

d by

the

pres

ence

of i

ts g

enet

ic

mat

eria

l or b

y its

ant

igen

s.

• Pr

edis

posi

tion

to a

gen

etic

dis

ease

can

be

dete

cted

thro

ugh

the

pres

ence

of

mar

kers

.

• D

NA

mic

roar

rays

can

be

used

to te

st fo

r gen

etic

pre

disp

ositi

on o

r to

diag

nose

th

e di

seas

e.

• M

etab

olite

s th

at in

dica

te d

isea

se c

an b

e de

tect

ed in

blo

od a

nd u

rine.

• Tr

acki

ng e

xper

imen

ts a

re u

sed

to g

ain

info

rmat

ion

abou

t the

loca

lizat

ion

and

inte

ract

ion

of a

des

ired

prot

ein.

• Bi

opha

rmin

g us

es g

enet

ical

ly m

odifi

ed a

nim

als

and

plan

ts to

pro

duce

pr

otei

ns fo

r the

rape

utic

use

.

• Vi

ral v

ecto

rs c

an b

e us

ed in

gen

e th

erap

y.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: U

se o

f PCR

to d

etec

t diff

eren

t str

ains

of i

nflu

enza

viru

s.

• A

pplic

atio

n: T

rack

ing

tum

our c

ells

usi

ng tr

ansf

erin

link

ed to

lum

ines

cent

pr

obes

.

Theo

ry o

f kno

wle

dge:

• Th

ere

have

bee

n ca

ses

arou

nd th

e w

orld

whe

re s

ubje

cts

have

die

d as

a

cons

eque

nce

of p

artic

ipat

ing

in a

gen

e th

erap

y re

sear

ch p

roto

col.

How

is th

e de

cisi

on to

pro

ceed

with

risk

y pr

oced

ures

mad

e?

• W

hat

cons

titu

tes

an a

ccep

tab

le le

vel o

f ri

sk f

or a

llow

ing

hum

ans

to b

e in

volv

ed in

sci

entif

ic re

sear

ch?

Uti

lizat

ion:

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Bi

olog

yTo

pic

3.5

Gen

etic

mod

ifica

tion

and

biot

echn

olog

yTo

pic

6.3

Def

ence

aga

inst

infe

ctio

us d

isea

seTo

pic

11.1

Ant

ibod

y pr

oduc

tion

and

vacc

inat

ion


Biology guide 125

B.4

Med

icin

e

• A

pplic

atio

n: B

ioph

arm

ing

of a

ntith

rom

bin.

• A

pplic

atio

n: U

se o

f vira

l vec

tors

in th

e tr

eatm

ent o

f Sev

ere

Com

bine

d Im

mun

odef

icie

ncy

(SCI

D).

• Sk

ill: A

naly

sis

of a

sim

ple

mic

roar

ray.

• Sk

ill: I

nter

pret

atio

n of

the

resu

lts o

f an

ELIS

A d

iagn

ostic

test

.


Biology guide126

Esse

ntia

l ide

a: B

ioin

form

atic

s is

the

use

of c

ompu

ters

to a

naly

se s

eque

nce

data

in b

iolo

gica

l res

earc

h.

B.5

Bioi

nfor

mat

ics

Nat

ure

of s

cien

ce:

Coop

erat

ion

and

colla

bora

tion

betw

een

grou

ps o

f sci

entis

ts—

data

base

s on

the

inte

rnet

allo

w s

cien

tists

free

acc

ess

to in

form

atio

n. (4

.3)

Und

erst

andi

ngs:

• D

atab

ases

allo

w s

cien

tists

eas

y ac

cess

to in

form

atio

n.

• Th

e bo

dy o

f dat

a st

ored

in d

atab

ases

is in

crea

sing

exp

onen

tially

.

• BL

AST

sea

rche

s ca

n id

entif

y si

mila

r seq

uenc

es in

diff

eren

t org

anis

ms.

• G

ene

func

tion

can

be s

tudi

ed u

sing

mod

el o

rgan

ism

s w

ith s

imila

r seq

uenc

es.

• Se

quen

ce a

lignm

ent s

oftw

are

allo

ws

com

paris

on o

f seq

uenc

es fr

om d

iffer

ent

orga

nism

s.

• BL

AST

n al

low

s nu

cleo

tide

sequ

ence

alig

nmen

t whi

le B

LAST

p al

low

s pr

otei

n al

ignm

ent.

• D

atab

ases

can

be

sear

ched

to c

ompa

re n

ewly

iden

tifie

d se

quen

ces

with

se

quen

ces

of k

now

n fu

nctio

n in

oth

er o

rgan

ism

s.

• M

ultip

le s

eque

nce

alig

nmen

t is

used

in th

e st

udy

of p

hylo

gene

tics.

• ES

T is

an

expr

esse

d se

quen

ce ta

g th

at c

an b

e us

ed to

iden

tify

pote

ntia

l ge

nes.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: U

se o

f kno

ckou

t tec

hnol

ogy

in m

ice

to d

eter

min

e ge

ne fu

nctio

n.

• A

pplic

atio

n: D

isco

very

of g

enes

by

EST

data

min

ing.

• Sk

ill: E

xplo

re c

hrom

osom

e 21

in d

atab

ases

(for

exa

mpl

e in

Ens

embl

).

• Sk

ill: U

se o

f sof

twar

e to

alig

n tw

o pr

otei

ns.

• Sk

ill: U

se o

f sof

twar

e to

con

stru

ct s

impl

e cl

adog

ram

s an

d ph

ylog

ram

s of

re

late

d or

gani

sms

usin

g D

NA

seq

uenc

es.

Theo

ry o

f kno

wle

dge:

• Kn

owle

dge

clai

ms

just

ified

by

refe

renc

e to

dat

abas

es ra

ise

uniq

ue

know

ledg

e qu

estio

ns. H

ow re

liabl

e ar

e kn

owle

dge

clai

ms

just

ified

by

refe

renc

e to

dat

a so

urce

s de

velo

ped

for d

iffer

ent p

urpo

ses

by d

iffer

ent

rese

arch

ers

usin

g di

ffer

ent m

etho

ds?

Aim

s:

• A

im 6

: Seq

uenc

e al

ignm

ent o

f rel

ated

pro

tein

s su

ch a

s he

mog

lobi

n an

d m

yogl

obin

cou

ld b

e in

vest

igat

ed.


Opt

ion

C: E

colo

gy a

nd c

onse

rvat

ion

15/2

5 ho

urs

Core

topi

cs

Esse

ntia

l ide

a: C

omm

unity

str

uctu

re is

an

emer

gent

pro

pert

y of

an

ecos

yste

m.

C.1

Spec

ies

and

com

mun

itie

s

Nat

ure

of s

cien

ce:

Use

mod

els

as re

pres

enta

tions

of t

he re

al w

orld

—zo

nes

of s

tres

s an

d lim

its o

f tol

eran

ce g

raph

s ar

e m

odel

s of

the

real

wor

ld th

at h

ave

pred

ictiv

e po

wer

and

exp

lain

co

mm

unity

str

uctu

re. (

1.10

)

Und

erst

andi

ngs:

• Th

e di

strib

utio

n of

spe

cies

is a

ffec

ted

by li

miti

ng fa

ctor

s.

• Co

mm

unity

str

uctu

re c

an b

e st

rong

ly a

ffec

ted

by k

eyst

one

spec

ies.

• Ea

ch s

peci

es p

lays

a u

niqu

e ro

le w

ithin

a c

omm

unity

bec

ause

of t

he u

niqu

e co

mbi

natio

n of

its

spat

ial h

abita

t and

inte

ract

ions

with

oth

er s

peci

es.

• In

tera

ctio

ns b

etw

een

spec

ies i

n a

com

mun

ity c

an b

e cl

assif

ied

acco

rdin

g to

thei

r effe

ct.

• Tw

o sp

ecie

s can

not s

urvi

ve in

defin

itely

in th

e sa

me

habi

tat i

f the

ir ni

ches

are

iden

tical

.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: D

istr

ibut

ion

of o

ne a

nim

al a

nd o

ne p

lant

spe

cies

to il

lust

rate

lim

its o

f to

lera

nce

and

zone

s of

str

ess.

• A

pplic

atio

n: L

ocal

exa

mpl

es to

illu

stra

te th

e ra

nge

of w

ays

in w

hich

spe

cies

can

in

tera

ct w

ithin

a c

omm

unity

.

• A

pplic

atio

n: T

he s

ymbi

otic

rela

tions

hip

betw

een

Zoox

anth

ella

e an

d re

ef-b

uild

ing

cora

l ree

f spe

cies

.

• Sk

ill: A

naly

sis

of a

dat

a se

t tha

t illu

stra

tes

the

dist

inct

ion

betw

een

fund

amen

tal

and

real

ized

nic

he.

• Sk

ill: U

se o

f a tr

anse

ct to

cor

rela

te th

e di

strib

utio

n of

pla

nt o

r ani

mal

spe

cies

with

an

abi

otic

var

iabl

e.

Theo

ry o

f kno

wle

dge:

• Ra

ndom

sam

ples

are

take

n in

stu

dies

invo

lvin

g la

rge

geog

raph

ical

ar

eas

or if

lim

ited

time

is a

vaila

ble.

Is ra

ndom

sam

plin

g a

usef

ul to

ol fo

r sc

ient

ists

des

pite

the

pote

ntia

l for

sam

plin

g bi

as?

Uti

lizat

ion:

Sylla

bus

and

cros

s-cu

rric

ular

link

s:G

eogr

aphy

Part

2C

Extr

eme

envi

ronm

ents

Aim

s:

• A

im 6

: Fac

tors

influ

enci

ng h

erbi

vory

cou

ld b

e in

vest

igat

ed.

Core topics

Biology guide128

Esse

ntia

l ide

a: C

hang

es in

com

mun

ity s

truc

ture

aff

ect a

nd a

re a

ffec

ted

by o

rgan

ism

s.

C.2

Com

mun

itie

s an

d ec

osys

tem

s

Nat

ure

of s

cien

ce:

Use

mod

els

as re

pres

enta

tions

of t

he re

al w

orld

—py

ram

ids

of e

nerg

y m

odel

the

ener

gy fl

ow th

roug

h ec

osys

tem

s. (1

.10)

Und

erst

andi

ngs:

• M

ost s

peci

es o

ccup

y di

ffer

ent t

roph

ic le

vels

in m

ultip

le fo

od c

hain

s.

• A

food

web

sho

ws

all t

he p

ossi

ble

food

cha

ins

in a

com

mun

ity.

• Th

e pe

rcen

tage

of i

nges

ted

ener

gy c

onve

rted

to b

iom

ass

is d

epen

dent

on

the

resp

iratio

n ra

te.

• Th

e ty

pe o

f sta

ble

ecos

yste

m th

at w

ill e

mer

ge in

an

area

is p

redi

ctab

le b

ased

on

clim

ate.

• In

clo

sed

ecos

yste

ms

ener

gy b

ut n

ot m

atte

r is

exch

ange

d w

ith th

e su

rrou

ndin

gs.

• D

istu

rban

ce in

fluen

ces

the

stru

ctur

e an

d ra

te o

f cha

nge

with

in e

cosy

stem

s.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: C

onve

rsio

n ra

tio in

sus

tain

able

food

pro

duct

ion

prac

tices

.

• A

pplic

atio

n: C

onsi

dera

tion

of o

ne e

xam

ple

of h

ow h

uman

s in

terf

ere

with

nu

trie

nt c

yclin

g.

• Sk

ill: C

ompa

rison

of p

yram

ids

of e

nerg

y fr

om d

iffer

ent e

cosy

stem

s.

• Sk

ill: A

naly

sis

of a

clim

ogra

ph s

how

ing

the

rela

tions

hip

betw

een

tem

pera

ture

, rai

nfal

l and

the

type

of e

cosy

stem

.

• Sk

ill: C

onst

ruct

ion

of G

ersm

ehl d

iagr

ams

to s

how

the

inte

r-re

latio

nshi

ps

betw

een

nutr

ient

sto

res

and

flow

s be

twee

n ta

iga,

des

ert a

nd tr

opic

al

rain

fore

st.

Theo

ry o

f kno

wle

dge:

• D

o th

e en

titie

s in

sci

entis

ts’ m

odel

s, fo

r exa

mpl

e tr

ophi

c le

vels

or G

ersm

ehl

diag

ram

s, a

ctua

lly e

xist

, or a

re th

ey p

rimar

ily u

sefu

l inv

entio

ns fo

r pre

dict

ing

and

expl

aini

ng th

e na

tura

l wor

ld?

Uti

lizat

ion:

• Po

ikilo

ther

ms

(ani

mal

s th

at h

ave

a va

riabl

e bo

dy te

mpe

ratu

re) a

re m

ore

effe

ctiv

e pr

oduc

ers

of p

rote

in th

an h

omeo

ther

ms

(ani

mal

s th

at m

aint

ain

a re

gula

ted

body

tem

pera

ture

) as

they

hav

e a

high

er ra

te o

f con

vers

ion

of fo

od

to b

iom

ass.

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Bi

olog

yTo

pic

4.2

Ener

gy fl

ow

Core topics

Biology guide 129

C.2

Com

mun

itie

s an

d ec

osys

tem

s

• Sk

ill: A

naly

sis

of d

ata

show

ing

prim

ary

succ

essi

on.

• Sk

ill: I

nves

tigat

ion

into

the

effe

ct o

f an

envi

ronm

enta

l dis

turb

ance

on

an

ecos

yste

m.

Gui

danc

e:

• Ex

ampl

es o

f asp

ects

to in

vest

igat

e in

the

ecos

yste

m c

ould

be

spec

ies

dive

rsity

, nut

rient

cyc

ling,

wat

er m

ovem

ent,

eros

ion,

leaf

are

a in

dex,

am

ong

othe

rs.

Core topics

Biology guide130

Esse

ntia

l ide

a: H

uman

act

iviti

es im

pact

on

ecos

yste

m fu

nctio

n.

C.3

Impa

cts

of h

uman

s on

eco

syst

ems

Nat

ure

of s

cien

ce:

Ass

essi

ng ri

sks

and

bene

fits

asso

ciat

ed w

ith s

cien

tific

rese

arch

—th

e us

e of

bio

logi

cal c

ontr

ol h

as a

ssoc

iate

d ris

k an

d re

quire

s ve

rific

atio

n by

tigh

tly c

ontr

olle

d ex

perim

ents

bef

ore

it is

app

rove

d. (4

.8)

Und

erst

andi

ngs:

• In

trod

uced

alie

n sp

ecie

s ca

n es

cape

into

loca

l eco

syst

ems

and

beco

me

inva

sive

.

• Co

mpe

titiv

e ex

clus

ion

and

the

abse

nce

of p

reda

tors

can

lead

to re

duct

ion

in

the

num

bers

of e

ndem

ic s

peci

es w

hen

alie

n sp

ecie

s be

com

e in

vasi

ve.

• Po

lluta

nts

beco

me

conc

entr

ated

in th

e tis

sues

of o

rgan

ism

s at

hig

her t

roph

ic

leve

ls b

y bi

omag

nific

atio

n.

• M

acro

plas

tic a

nd m

icro

plas

tic d

ebris

has

acc

umul

ated

in m

arin

e en

viro

nmen

ts.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: S

tudy

of t

he in

trod

uctio

n of

can

e to

ads

in A

ustr

alia

and

one

ot

her l

ocal

exa

mpl

e of

the

intr

oduc

tion

of a

n al

ien

spec

ies.

• A

pplic

atio

n: D

iscu

ssio

n of

the

trad

e-of

f bet

wee

n co

ntro

l of t

he m

alar

ial

para

site

and

DD

T po

llutio

n.

• A

pplic

atio

n: C

ase

stud

y of

the

impa

ct o

f mar

ine

plas

tic d

ebris

on

Lays

an

alba

tros

ses

and

one

othe

r nam

ed s

peci

es.

• Sk

ill: A

naly

sis

of d

ata

illus

trat

ing

the

caus

es a

nd c

onse

quen

ces

of

biom

agni

ficat

ion.

• Sk

ill: E

valu

atio

n of

era

dica

tion

prog

ram

mes

and

bio

logi

cal c

ontr

ol a

s m

easu

res

to re

duce

the

impa

ct o

f alie

n sp

ecie

s.

Inte

rnat

iona

l-m

inde

dnes

s:

• O

ver 1

00 c

ount

ries

acro

ss th

e gl

obe

have

agr

eed

to b

an th

e pr

oduc

tion

of

CFCs

to re

duce

the

depl

etio

n of

the

ozon

e la

yer.

Aim

s:

• A

im 8

: Man

y de

velo

ped

coun

trie

s ex

port

toxi

c w

aste

to le

ss d

evel

oped

co

untr

ies.

Is fi

nanc

ial c

ompe

nsat

ion

a fa

ir ex

chan

ge fo

r haz

ardo

us w

aste

?

Core topics

Biology guide 131

Esse

ntia

l ide

a: E

ntire

com

mun

ities

nee

d to

be

cons

erve

d in

ord

er to

pre

serv

e bi

odiv

ersi

ty.

C.4

Cons

erva

tion

of b

iodi

vers

ity

Nat

ure

of s

cien

ce:

Scie

ntist

s col

labo

rate

with

oth

er a

genc

ies—

the

pres

erva

tion

of sp

ecie

s inv

olve

s int

erna

tiona

l coo

pera

tion

thro

ugh

inte

rgov

ernm

enta

l and

non

-gov

ernm

enta

l org

aniz

atio

ns. (

4.3)

Und

erst

andi

ngs:

• A

n in

dica

tor s

peci

es is

an

orga

nism

use

d to

ass

ess

a sp

ecifi

c en

viro

nmen

tal

cond

ition

.

• Re

lativ

e nu

mbe

rs o

f ind

icat

or s

peci

es c

an b

e us

ed to

cal

cula

te th

e va

lue

of a

bi

otic

inde

x.

• In

situ

con

serv

atio

n m

ay re

quire

act

ive

man

agem

ent o

f nat

ure

rese

rves

or

natio

nal p

arks

.

• Ex

situ

con

serv

atio

n is

the

pres

erva

tion

of sp

ecie

s out

side

thei

r nat

ural

hab

itats

.

• Bi

ogeo

grap

hic

fact

ors

affe

ct s

peci

es d

iver

sity

.

• Ri

chne

ss a

nd e

venn

ess

are

com

pone

nts

of b

iodi

vers

ity.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: C

ase

stud

y of

the

capt

ive

bree

ding

and

rein

trod

uctio

n of

an

enda

nger

ed a

nim

al s

peci

es.

• A

pplic

atio

n: A

naly

sis

of th

e im

pact

of b

ioge

ogra

phic

fact

ors

on d

iver

sity

lim

ited

to is

land

siz

e an

d ed

ge e

ffec

ts.

• Sk

ill: A

naly

sis

of th

e bi

odiv

ersi

ty o

f tw

o lo

cal c

omm

uniti

es u

sing

Sim

pson

’s re

cipr

ocal

inde

x of

div

ersi

ty.

Gui

danc

e:

• Th

e fo

rmul

a fo

r Sim

pson

’s re

cipr

ocal

inde

x of

div

ersi

ty is

:

D =

div

ersi

ty in

dex,

N =

tota

l num

ber o

f org

anis

ms o

f all

spec

ies f

ound

and

n =

nu

mbe

r of i

ndiv

idua

ls o

f a p

artic

ular

spe

cies

.

Aim

s:

• A

im 8

: Sci

entis

ts s

uppo

rted

by

gove

rnm

ents

are

dev

otin

g re

lativ

ely

larg

e am

ount

s of

eff

ort t

o sa

ve p

artic

ular

ani

mal

spe

cies

. Can

crit

eria

be

esta

blis

hed

to ju

stify

a h

iera

rchy

of v

alue

of o

ne s

peci

es o

ver a

noth

er?

Biology guide132

Opt

ion

C: E

colo

gy a

nd c

onse

rvat

ion

15/2

5 ho

urs

Addi

tiona

l hig

her l

evel

topi

cs

Esse

ntia

l ide

a: D

ynam

ic b

iolo

gica

l pro

cess

es im

pact

pop

ulat

ion

dens

ity a

nd p

opul

atio

n gr

owth

.

C.5

Popu

lati

on e

colo

gy

Nat

ure

of s

cien

ce:

Avoi

ding

bia

s—a

rand

om n

umbe

r gen

erat

or h

elps

to e

nsur

e po

pula

tion

sam

plin

g is

free

from

bia

s. (5

.4)

Und

erst

andi

ngs:

• Sa

mpl

ing

tech

niqu

es a

re u

sed

to e

stim

ate

popu

latio

n si

ze.

• Th

e ex

pone

ntia

l gro

wth

pat

tern

occ

urs

in a

n id

eal,

unlim

ited

envi

ronm

ent.

• Po

pula

tion

grow

th s

low

s as

a p

opul

atio

n re

ache

s th

e ca

rryi

ng c

apac

ity o

f the

en

viro

nmen

t.

• Th

e ph

ases

sho

wn

in th

e si

gmoi

d cu

rve

can

be e

xpla

ined

by

rela

tive

rate

s of

na

talit

y, m

orta

lity,

imm

igra

tion

and

emig

ratio

n.

• Li

miti

ng fa

ctor

s ca

n be

top

dow

n or

bot

tom

up.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: E

valu

atin

g th

e m

etho

ds u

sed

to e

stim

ate

the

size

of c

omm

erci

al

stoc

k of

mar

ine

reso

urce

s.

• A

pplic

atio

n: U

se o

f the

cap

ture

-mar

k-re

leas

e-re

capt

ure

met

hod

to e

stim

ate

the

popu

latio

n si

ze o

f an

anim

al s

peci

es.

• A

pplic

atio

n: D

iscu

ssio

n of

the

effe

ct o

f nat

ality

, mor

talit

y, im

mig

ratio

n an

d em

igra

tion

on p

opul

atio

n si

ze.

Inte

rnat

iona

l-m

inde

dnes

s:

• Th

e is

sues

aro

und

the

grow

ing

glob

al h

uman

pop

ulat

ion

are

of in

tern

atio

nal

conc

ern

rega

rdle

ss o

f diff

eren

t gro

wth

rate

s in

diff

eren

t cou

ntrie

s.

Uti

lizat

ion:

Sylla

bus

and

cros

s-cu

rric

ular

link

s:G

eogr

aphy

Part

1.1

Pop

ulat

ions

in tr

ansi

tion

Envi

ronm

enta

l sys

tem

s an

d so

ciet

ies

Topi

c 8.

4 H

uman

pop

ulat

ion

carr

ying

cap

acity


Biology guide 133

C.5

Popu

lati

on e

colo

gy

• A

pplic

atio

n: A

naly

sis

of th

e ef

fect

of p

opul

atio

n si

ze, a

ge a

nd re

prod

uctiv

e st

atus

on

sust

aina

ble

fishi

ng p

ract

ices

.

• A

pplic

atio

n: B

otto

m-u

p co

ntro

l of a

lgal

blo

oms

by s

hort

age

of n

utrie

nts

and

top-

dow

n co

ntro

l by

herb

ivor

y.

• Sk

ill: M

odel

ling

the

grow

th c

urve

usi

ng a

sim

ple

orga

nism

suc

h as

yea

st o

r sp

ecie

s of

Lem

na.


Biology guide134

Esse

ntia

l ide

a: S

oil c

ycle

s ar

e su

bjec

t to

disr

uptio

n.

C.6

Nit

roge

n an

d ph

osph

orus

cyc

les

Nat

ure

of s

cien

ce:

Ass

essi

ng ri

sks

and

bene

fits

of s

cien

tific

rese

arch

—ag

ricul

tura

l pra

ctic

es c

an d

isru

pt th

e ph

osph

orus

cyc

le. (

4.8)

Und

erst

andi

ngs:

• N

itrog

en-f

ixin

g ba

cter

ia c

onve

rt a

tmos

pher

ic n

itrog

en to

am

mon

ia.

• Rh

izob

ium

ass

ocia

tes

with

root

s in

a m

utua

listic

rela

tions

hip.

• In

the

abse

nce

of o

xyge

n de

nitr

ifyin

g ba

cter

ia re

duce

nitr

ate

in th

e so

il.

• Ph

osph

orus

can

be

adde

d to

the

phos

phor

us c

ycle

by

appl

icat

ion

of fe

rtili

zer

or re

mov

ed b

y th

e ha

rves

ting

of a

gric

ultu

ral c

rops

.

• Th

e ra

te o

f tur

nove

r in

the

phos

phor

us c

ycle

is m

uch

low

er th

an th

e ni

trog

en

cycl

e.

• Av

aila

bilit

y of

pho

spha

te m

ay b

ecom

e lim

iting

to a

gric

ultu

re in

the

futu

re.

• Le

achi

ng o

f min

eral

nut

rient

s fr

om a

gric

ultu

ral l

and

into

rive

rs c

ause

s eu

trop

hica

tion

and

lead

s to

incr

ease

d bi

oche

mic

al o

xyge

n de

man

d.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: T

he im

pact

of w

ater

logg

ing

on th

e ni

trog

en c

ycle

.

• A

pplic

atio

n: In

sect

ivor

ous

plan

ts a

s an

ada

ptat

ion

for l

ow n

itrog

en

avai

labi

lity

in w

ater

logg

ed s

oils

.

• Sk

ill: D

raw

ing

and

labe

lling

a d

iagr

am o

f the

nitr

ogen

cyc

le.

• Sk

ill: A

sses

s th

e nu

trie

nt c

onte

nt o

f a s

oil s

ampl

e.

Uti

lizat

ion:

• Cr

op ro

tatio

ns a

llow

the

rene

wal

of s

oil n

utrie

nts

by a

llow

ing

an a

rea

to

rem

ain

“fal

low

”.


Opt

ion

D: H

uman

phy

siol

ogy

15/2

5 ho

urs

Core

topi

cs

Esse

ntia

l ide

a: A

bal

ance

d di

et is

ess

entia

l to

hum

an h

ealth

.

D.1

Hum

an n

utri

tion

Nat

ure

of s

cien

ce:

Fals

ifica

tion

of th

eorie

s w

ith o

ne th

eory

bei

ng s

uper

sede

d by

ano

ther

—sc

urvy

was

thou

ght t

o be

spe

cific

to h

uman

s, b

ecau

se a

ttem

pts

to in

duce

the

sym

ptom

s in

la

bora

tory

rats

and

mic

e w

ere

entir

ely

unsu

cces

sful

. (1.

9)

Und

erst

andi

ngs:

• Es

sent

ial n

utrie

nts

cann

ot b

e sy

nthe

size

d by

the

body

, the

refo

re th

ey h

ave

to

be in

clud

ed in

the

diet

.

• D

ieta

ry m

iner

als

are

esse

ntia

l che

mic

al e

lem

ents

.

• Vi

tam

ins

are

chem

ical

ly d

iver

se c

arbo

n co

mpo

unds

that

can

not b

e sy

nthe

size

d by

the

body

.

• So

me

fatt

y ac

ids

and

som

e am

ino

acid

s ar

e es

sent

ial.

• La

ck o

f ess

entia

l am

ino

acid

s af

fect

s th

e pr

oduc

tion

of p

rote

ins.

• M

alnu

triti

on m

ay b

e ca

used

by

a de

ficie

ncy,

imba

lanc

e or

exc

ess

of n

utrie

nts

in th

e di

et.

• A

ppet

ite is

con

trol

led

by a

cen

tre

in th

e hy

poth

alam

us.

• O

verw

eigh

t ind

ivid

uals

are

mor

e lik

ely

to s

uffe

r hyp

erte

nsio

n an

d ty

pe II

di

abet

es.

• St

arva

tion

can

lead

to b

reak

dow

n of

bod

y tis

sue.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: P

rodu

ctio

n of

asc

orbi

c ac

id b

y so

me

mam

mal

s, b

ut n

ot o

ther

s th

at n

eed

a di

etar

y su

pply

.

• A

pplic

atio

n: C

ause

and

trea

tmen

t of p

heny

lket

onur

ia (P

KU).

Inte

rnat

iona

l-m

inde

dnes

s:

• Th

e Vi

tam

in a

nd M

iner

al N

utrit

ion

Info

rmat

ion

Syst

em (V

MN

IS),

form

erly

kn

own

as th

e M

icro

nutr

ient

Def

icie

ncy

Info

rmat

ion

Syst

em (M

DIS

), w

as

esta

blis

hed

in 1

991

follo

win

g a

requ

est b

y th

e W

orld

Hea

lth A

ssem

bly

to

stre

ngth

en s

urve

illan

ce o

f mic

ronu

trie

nt d

efic

ienc

ies

at th

e gl

obal

leve

l.

Theo

ry o

f kno

wle

dge:

• Th

ere

are

posi

tive

effe

cts

of e

xpos

ure

to s

un s

uch

as th

e pr

oduc

tion

of

Vita

min

D a

s w

ell a

s he

alth

risk

s as

soci

ated

with

exp

osur

e to

UV

rays

. How

ca

n co

nflic

ting

know

ledg

e cl

aim

s be

bal

ance

d?

Uti

lizat

ion:

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Bi

olog

yTo

pic

6.1

Dig

estio

n an

d ab

sorp

tion

Geo

grap

hyPa

rt 2

F Th

e ge

ogra

phy

of fo

od a

nd h

ealth

Chem

istr

yTo

pic

B5 V

itam

ins

Core topics

Biology guide136

D.1

Hum

an n

utri

tion

• A

pplic

atio

n: L

ack

of V

itam

in D

or c

alci

um c

an a

ffec

t bon

e m

iner

aliz

atio

n an

d ca

use

ricke

ts o

r ost

eom

alac

ia.

• A

pplic

atio

n: B

reak

dow

n of

hea

rt m

uscl

e du

e to

ano

rexi

a.

• A

pplic

atio

n: C

hole

ster

ol in

blo

od a

s an

indi

cato

r of t

he ri

sk o

f cor

onar

y he

art

dise

ase.

• Sk

ill: D

eter

min

atio

n of

the

ener

gy c

onte

nt o

f foo

d by

com

bust

ion.

• Sk

ill: U

se o

f dat

abas

es o

f nut

ritio

nal c

onte

nt o

f foo

ds a

nd s

oftw

are

to

calc

ulat

e in

take

s of

ess

entia

l nut

rient

s fr

om a

dai

ly d

iet.

Core topics

Biology guide 137

Esse

ntia

l ide

a: D

iges

tion

is c

ontr

olle

d by

ner

vous

and

hor

mon

al m

echa

nism

s.

D.2

Dig

esti

on

Nat

ure

of s

cien

ce:

Sere

ndip

ity a

nd s

cien

tific

dis

cove

ries—

the

role

of g

astr

ic a

cid

in d

iges

tion

was

est

ablis

hed

by W

illia

m B

eaum

ont w

hile

obs

ervi

ng th

e pr

oces

s of

dig

estio

n in

an

open

w

ound

cau

sed

by g

unsh

ot. (

1.4)

Und

erst

andi

ngs:

• N

ervo

us a

nd h

orm

onal

mec

hani

sms

cont

rol t

he s

ecre

tion

of d

iges

tive

juic

es.

• Ex

ocrin

e gl

ands

sec

rete

to th

e su

rfac

e of

the

body

or t

he lu

men

of t

he g

ut.

• Th

e vo

lum

e an

d co

nten

t of g

astr

ic s

ecre

tions

are

con

trol

led

by n

ervo

us a

nd

horm

onal

mec

hani

sms.

• A

cid

cond

ition

s in

the

stom

ach

favo

ur s

ome

hydr

olys

is re

actio

ns a

nd h

elp

to

cont

rol p

atho

gens

in in

gest

ed fo

od.

• Th

e st

ruct

ure

of c

ells

of t

he e

pith

eliu

m o

f the

vill

i is

adap

ted

to th

e ab

sorp

tion

of fo

od.

• Th

e ra

te o

f tra

nsit

of m

ater

ials

thro

ugh

the

larg

e in

test

ine

is p

ositi

vely

co

rrel

ated

with

thei

r fib

re c

onte

nt.

• M

ater

ials

not

abs

orbe

d ar

e eg

este

d.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: T

he re

duct

ion

of s

tom

ach

acid

sec

retio

n by

pro

ton

pum

p in

hibi

tor d

rugs

.

• A

pplic

atio

n: D

ehyd

ratio

n du

e to

cho

lera

toxi

n.

• A

pplic

atio

n: H

elic

obac

ter p

ylor

i inf

ectio

n as

a c

ause

of s

tom

ach

ulce

rs.

• Sk

ill: I

dent

ifica

tion

of e

xocr

ine

glan

d ce

lls th

at s

ecre

te d

iges

tive

juic

es a

nd

villu

s ep

ithel

ium

cel

ls th

at a

bsor

b di

gest

ed fo

ods

from

ele

ctro

n m

icro

grap

hs.

Gui

danc

e:

• A

dapt

atio

ns o

f vill

us e

pith

elia

l cel

ls in

clud

e m

icro

villi

and

mito

chon

dria

.

Uti

lizat

ion:

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Bi

olog

yTo

pic

1.2

Ultr

astr

uctu

re o

f cel

lsTo

pic

6.5

Neu

rons

and

syn

apse

sCh

emis

try

Topi

c D

4 pH

regu

latio

n of

sto

mac

h

Core topics

Biology guide138

Esse

ntia

l ide

a: T

he c

hem

ical

com

posi

tion

of th

e bl

ood

is re

gula

ted

by th

e liv

er.

D.3

Fun

ctio

ns o

f the

live

r

Nat

ure

of s

cien

ce:

Educ

atin

g th

e pu

blic

on

scie

ntifi

c cl

aim

s—sc

ient

ific

stud

ies

have

sho

wn

that

hig

h-de

nsity

lipo

prot

ein

coul

d be

con

side

red

“goo

d” c

hole

ster

ol. (

5.2)

Und

erst

andi

ngs:

• Th

e liv

er re

mov

es to

xins

from

the

bloo

d an

d de

toxi

fies

them

.

• Co

mpo

nent

s of

red

bloo

d ce

lls a

re re

cycl

ed b

y th

e liv

er.

• Th

e br

eakd

own

of e

ryth

rocy

tes

star

ts w

ith p

hago

cyto

sis

of re

d bl

ood

cells

by

Kupf

fer c

ells

.

• Iro

n is

car

ried

to th

e bo

ne m

arro

w to

pro

duce

hem

oglo

bin

in n

ew re

d bl

ood

cells

.

• Su

rplu

s ch

oles

tero

l is

conv

erte

d to

bile

sal

ts.

• En

dopl

asm

ic re

ticul

um a

nd G

olgi

app

arat

us in

hep

atoc

ytes

pro

duce

pla

sma

prot

eins

.

• Th

e liv

er in

terc

epts

blo

od fr

om th

e gu

t to

regu

late

nut

rient

leve

ls.

• So

me

nutr

ient

s in

exc

ess

can

be s

tore

d in

the

liver

.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: C

ause

s an

d co

nseq

uenc

es o

f jau

ndic

e.

• A

pplic

atio

n: D

ual b

lood

sup

ply

to th

e liv

er a

nd d

iffer

ence

s be

twee

n si

nuso

ids

and

capi

llarie

s.

Theo

ry o

f kno

wle

dge:

• Ex

cess

ive

alco

hol c

onsu

mpt

ion

may

cau

se li

ver c

irrho

sis.

Are

att

itude

s to

dr

ugs

and

alco

hol a

n ex

ampl

e of

som

ethi

ng th

at is

rela

tive

to c

ultu

re?

Is a

ll kn

owle

dge

depe

nden

t on

cultu

re?

Aim

s:

• A

im 6

: Tem

pora

ry m

ount

s of

hep

atoc

ytes

can

be

prep

ared

from

fres

h liv

er.

• A

im 8

: Giv

en th

e pr

essu

re o

n he

alth

reso

urce

s, e

spec

ially

the

avai

labi

lity

of

orga

ns fo

r tra

nspl

ant,

shou

ld a

n al

coho

lic b

e al

low

ed a

live

r tra

nspl

ant?

Core topics

Biology guide 139

Esse

ntia

l ide

a: In

tern

al a

nd e

xter

nal f

acto

rs in

fluen

ce h

eart

func

tion.

D.4

The

hea

rt

Nat

ure

of s

cien

ce:

Dev

elop

men

ts in

sci

entif

ic re

sear

ch fo

llow

ed im

prov

emen

ts in

app

arat

us o

r ins

trum

enta

tion—

the

inve

ntio

n of

the

stet

hosc

ope

led

to im

prov

ed k

now

ledg

e of

the

wor

king

s of

the

hear

t. (1

.8)

Und

erst

andi

ngs:

• St

ruct

ure

of c

ardi

ac m

uscl

e ce

lls a

llow

s pr

opag

atio

n of

stim

uli t

hrou

gh th

e he

art w

all.

• Si

gnal

s fr

om th

e si

noat

rial n

ode

that

cau

se c

ontr

actio

n ca

nnot

pas

s di

rect

ly

from

atr

ia to

ven

tric

les.

• Th

ere

is a

del

ay b

etw

een

the

arriv

al a

nd p

assi

ng o

n of

a s

timul

us a

t the

at

riove

ntric

ular

nod

e.

• Th

is d

elay

allo

ws t

ime

for a

tria

l sys

tole

bef

ore

the

atrio

vent

ricul

ar v

alve

s clo

se.

• Co

nduc

ting

fibre

s en

sure

coo

rdin

ated

con

trac

tion

of th

e en

tire

vent

ricle

wal

l.

• N

orm

al h

eart

sou

nds

are

caus

ed b

y th

e at

riove

ntric

ular

val

ves

and

sem

iluna

r va

lves

clo

sing

cau

sing

cha

nges

in b

lood

flow

.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: U

se o

f art

ifici

al p

acem

aker

s to

regu

late

the

hear

t rat

e.

• A

pplic

atio

n: U

se o

f def

ibril

latio

n to

trea

t life

-thr

eate

ning

car

diac

con

ditio

ns.

• A

pplic

atio

n: C

ause

s an

d co

nseq

uenc

es o

f hyp

erte

nsio

n an

d th

rom

bosi

s.

• Sk

ill: M

easu

rem

ent a

nd in

terp

reta

tion

of th

e he

art r

ate

unde

r diff

eren

t co

nditi

ons.

• Sk

ill: I

nter

pret

atio

n of

sys

tolic

and

dia

stol

ic b

lood

pre

ssur

e m

easu

rem

ents

.

• Sk

ill: M

appi

ng o

f the

car

diac

cyc

le to

a n

orm

al E

CG tr

ace.

• Sk

ill: A

naly

sis

of e

pide

mio

logi

cal d

ata

rela

ting

to th

e in

cide

nce

of c

oron

ary

hear

t dis

ease

.

Gui

danc

e:

• In

clud

e br

anch

ing

and

inte

rcal

ated

dis

cs in

str

uctu

re o

f car

diac

mus

cle.

Theo

ry o

f kno

wle

dge:

• Sy

mbo

ls a

re u

sed

as a

form

of n

on-v

erba

l com

mun

icat

ion.

Why

is th

e he

art

used

as

a sy

mbo

l for

love

? W

hat i

s th

e im

port

ance

of s

ymbo

ls in

diff

eren

t ar

eas

of k

now

ledg

e?

Biology guide140

Opt

ion

D: H

uman

phy

siol

ogy

15/2

5 ho

urs

Addi

tiona

l hig

her l

evel

topi

cs

Esse

ntia

l ide

a: H

orm

ones

are

not

sec

rete

d at

a u

nifo

rm ra

te a

nd e

xert

thei

r eff

ect a

t low

con

cent

ratio

ns.

D.5

Hor

mon

es a

nd m

etab

olis

m

Nat

ure

of s

cien

ce:

Coop

erat

ion

and

colla

bora

tion

betw

een

grou

ps o

f sci

entis

ts—

the

Inte

rnat

iona

l Cou

ncil

for t

he C

ontr

ol o

f Iod

ine

Def

icie

ncy

Dis

orde

rs in

clud

es a

num

ber o

f sci

entis

ts

who

wor

k to

elim

inat

e th

e ha

rm d

one

by io

dine

def

icie

ncy.

(4.3

)

Und

erst

andi

ngs:

• En

docr

ine

glan

ds s

ecre

te h

orm

ones

dire

ctly

into

the

bloo

dstr

eam

.

• St

eroi

d ho

rmon

es b

ind

to re

cept

or p

rote

ins

in th

e cy

topl

asm

of t

he ta

rget

ce

ll to

form

a re

cept

or–h

orm

one

com

plex

.

• Th

e re

cept

or–h

orm

one

com

plex

pro

mot

es th

e tr

ansc

riptio

n of

spe

cific

ge

nes.

• Pe

ptid

e ho

rmon

es b

ind

to re

cept

ors

in th

e pl

asm

a m

embr

ane

of th

e ta

rget

ce

ll.

• Bi

ndin

g of

hor

mon

es to

mem

bran

e re

cept

ors

activ

ates

a c

asca

de m

edia

ted

by a

sec

ond

mes

seng

er in

side

the

cell.

• Th

e hy

poth

alam

us c

ontr

ols

horm

one

secr

etio

n by

the

ante

rior a

nd p

oste

rior

lobe

s of

the

pitu

itary

gla

nd.

• H

orm

ones

sec

rete

d by

the

pitu

itary

con

trol

gro

wth

, dev

elop

men

tal c

hang

es,

repr

oduc

tion

and

hom

eost

asis

.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: S

ome

athl

etes

take

gro

wth

hor

mon

es to

bui

ld m

uscl

es.

• A

pplic

atio

n: C

ontr

ol o

f milk

sec

retio

n by

oxy

toci

n an

d pr

olac

tin.

Aim

s:

• A

im 8

: The

re a

re n

umer

ous

drug

s th

at c

an e

nhan

ce p

erfo

rman

ce. I

s th

e us

e of

thes

e dr

ugs

acce

ptab

le in

term

s of

con

duct

ing

a fa

ir te

st a

s lo

ng a

s al

l at

hlet

es h

ave

equa

l acc

ess

to th

em?


Biology guide 141

Esse

ntia

l ide

a: R

ed b

lood

cel

ls a

re v

ital i

n th

e tr

ansp

ort o

f res

pira

tory

gas

es.

D.6

Tra

nspo

rt o

f res

pira

tory

gas

es

Nat

ure

of s

cien

ce:

Scie

ntis

ts h

ave

a ro

le in

info

rmin

g th

e pu

blic

—sc

ient

ific

rese

arch

has

led

to a

cha

nge

in p

ublic

per

cept

ion

of s

mok

ing.

(5.1)

Und

erst

andi

ngs:

• O

xyge

n di

ssoc

iatio

n cu

rves

sho

w th

e af

finity

of h

emog

lobi

n fo

r oxy

gen.

• Ca

rbon

dio

xide

is c

arrie

d in

sol

utio

n an

d bo

und

to h

emog

lobi

n in

the

bloo

d.

• Ca

rbon

dio

xide

is tr

ansf

orm

ed in

red

bloo

d ce

lls in

to h

ydro

genc

arbo

nate

io

ns.

• Th

e Bo

hr s

hift

exp

lain

s th

e in

crea

sed

rele

ase

of o

xyge

n by

hem

oglo

bin

in

resp

iring

tiss

ues.

• Ch

emor

ecep

tors

are

sen

sitiv

e to

cha

nges

in b

lood

pH

.

• Th

e ra

te o

f ven

tilat

ion

is c

ontr

olle

d by

the

resp

irato

ry c

ontr

ol c

entr

e in

the

med

ulla

obl

onga

ta.

• D

urin

g ex

erci

se th

e ra

te o

f ven

tilat

ion

chan

ges

in re

spon

se to

the

amou

nt o

f CO

2 in

the

bloo

d.

• Fe

tal h

emog

lobi

n is

diff

eren

t fro

m a

dult

hem

oglo

bin

allo

win

g th

e tr

ansf

er o

f ox

ygen

in th

e pl

acen

ta o

nto

the

feta

l hem

oglo

bin.

App

licat

ions

and

ski

lls:

• A

pplic

atio

n: C

onse

quen

ces

of h

igh

altit

ude

for g

as e

xcha

nge.

• A

pplic

atio

n: p

H o

f blo

od is

regu

late

d to

sta

y w

ithin

the

narr

ow ra

nge

of 7

.35

to 7

.45.

• A

pplic

atio

n: C

ause

s an

d tr

eatm

ents

of e

mph

ysem

a.

• Sk

ill: A

naly

sis

of d

isso

ciat

ion

curv

es fo

r hem

oglo

bin

and

myo

glob

in.

• Sk

ill: I

dent

ifica

tion

of p

neum

ocyt

es, c

apill

ary

endo

thel

ium

cel

ls a

nd b

lood

ce

lls in

ligh

t mic

rogr

aphs

and

ele

ctro

n m

icro

grap

hs o

f lun

g tis

sue.

Uti

lizat

ion:

• Tr

aini

ng c

amps

for a

thle

tes

are

freq

uent

ly lo

cate

d at

hig

h al

titud

e to

incr

ease

th

e he

mog

lobi

n co

nten

t of t

he b

lood

. Thi

s pu

ts th

e at

hlet

e at

an

adva

ntag

e w

hen

they

retu

rn to

low

er g

roun

d fo

r com

petit

ion.

Sylla

bus

and

cros

s-cu

rric

ular

link

s:Bi

olog

yTo

pic

6.4

Gas

exc

hang

ePh

ysic

sTo

pic

3.2

Mod

ellin

g a

gas

Aim

s:

• A

im 8

: Som

e sp

orts

, suc

h as

hig

h-al

titud

e m

ount

ain

clim

bing

or s

cuba

di

ving

, may

pus

h th

e lim

its o

f the

hum

an b

ody

beyo

nd e

ndur

ance

and

cau

se

dam

age.

Sho

uld

they

be

cont

rolle

d or

ban

ned?

Biology guide142142

Assessment

Assessment in the Diploma Programme

GeneralAssessment is an integral part of teaching and learning. The most important aims of assessment in the Diploma Programme are that it should support curricular goals and encourage appropriate student learning. Both external and internal assessments are used in the Diploma Programme. IB examiners mark work produced for external assessment, while work produced for internal assessment is marked by teachers and externally moderated by the IB.

There are two types of assessment identified by the IB.

• Formative assessment informs both teaching and learning. It is concerned with providing accurate and helpful feedback to students and teachers on the kind of learning taking place and the nature of students’ strengths and weaknesses in order to help develop students’ understanding and capabilities. Formative assessment can also help to improve teaching quality, as it can provide information to monitor progress towards meeting the course aims and objectives.

• Summative assessment gives an overview of previous learning and is concerned with measuring student achievement.

The Diploma Programme primarily focuses on summative assessment designed to record student achievement at, or towards the end of, the course of study. However, many of the assessment instruments can also be used formatively during the course of teaching and learning, and teachers are encouraged to do this. A comprehensive assessment plan is viewed as being integral with teaching, learning and course organization. For further information, see the IB Programme standards and practices document.

The approach to assessment used by the IB is criterion-related, not norm-referenced. This approach to assessment judges students’ work by their performance in relation to identified levels of attainment, and not in relation to the work of other students. For further information on assessment within the Diploma Programme please refer to the publication Diploma Programme assessment: Principles and practice.

To support teachers in the planning, delivery and assessment of the Diploma Programme courses, a variety of resources can be found on the OCC or purchased from the IB store (http://store.ibo.org). Additional publications such as specimen papers and markschemes, teacher support materials, subject reports and grade descriptors can also be found on the OCC. Past examination papers as well as markschemes can be purchased from the IB store.

Methods of assessmentThe IB uses several methods to assess work produced by students.

Assessment criteriaAssessment criteria are used when the assessment task is open-ended. Each criterion concentrates on a particular skill that students are expected to demonstrate. An assessment objective describes what students should be able to do, and assessment criteria describe how well they should be able to do it. Using assessment criteria allows discrimination between different answers and encourages a variety of responses.

Assessment in the Diploma Programme

Biology guide 143

Each criterion comprises a set of hierarchically ordered level descriptors. Each level descriptor is worth one or more marks. Each criterion is applied independently using a best-fit model. The maximum marks for each criterion may differ according to the criterion’s importance. The marks awarded for each criterion are added together to give the total mark for the piece of work.

MarkbandsMarkbands are a comprehensive statement of expected performance against which responses are judged. They represent a single holistic criterion divided into level descriptors. Each level descriptor corresponds to a range of marks to differentiate student performance. A best-fit approach is used to ascertain which particular mark to use from the possible range for each level descriptor.

Analytic markschemesAnalytic markschemes are prepared for those examination questions that expect a particular kind of response and/or a given final answer from students. They give detailed instructions to examiners on how to break down the total mark for each question for different parts of the response.

Marking notesFor some assessment components marked using assessment criteria, marking notes are provided. Marking notes give guidance on how to apply assessment criteria to the particular requirements of a question.

Inclusive assessment arrangementsInclusive assessment arrangements are available for candidates with assessment access requirements. These arrangements enable candidates with diverse needs to access the examinations and demonstrate their knowledge and understanding of the constructs being assessed.

The IB document Candidates with assessment access requirements provides details on all the inclusive assessment arrangements available to candidates with learning support requirements. The IB document Learning diversity within the International Baccalaureate programmes/Special educational needs within the International Baccalaureate programmes outlines the position of the IB with regard to candidates with diverse learning needs in the IB programmes. For candidates affected by adverse circumstances, the IB documents General regulations: Diploma Programme and the Handbook of procedures for the Diploma Programme provide details on access consideration.

Responsibilities of the schoolThe school is required to ensure that equal access arrangements and reasonable adjustments are provided to candidates with learning support requirements that are in line with the IB documents Candidates with assessment access requirements and Learning diversity within the International Baccalaureate programmes/Special educational needs within the International Baccalaureate programmes.

Biology guide144144

Assessment

Assessment outline—SL


Component Overall weighting (%)

Approximate weighting of objectives (%)

Duration (hours)

1+2 3

Paper 1 20 10 10 ¾

Paper 2 40 20 20 1¼

Paper 3 20 10 10 1

Internal assessment

20Covers objectives

1, 2, 3 and 410

Biology guide 145145

Assessment

Assessment outline—HL


Component Overall weighting (%)

Approximate weighting of objectives (%)

Duration (hours)

1+2 3

Paper 1 20 10 10 1

Paper 2 36 18 18 2¼

Paper 3 24 12 12 1¼

Internal assessment

20Covers objectives

1, 2, 3 and 410

Biology guide146146

Assessment

External assessment

Detailed markschemes specific to each examination paper are used to assess students.

External assessment details—SL

Paper 1Duration: ¾ hourWeighting: 20%Marks: 30• 30 multiple-choice questions on core material, about 15 of which are common with HL.

• The questions on paper 1 test assessment objectives 1, 2 and 3.

• The use of calculators is not permitted.

• No marks are deducted for incorrect answers.

Paper 2Duration: 1¼ hoursWeighting: 40%Marks: 50• Data-based question.

• Short-answer and extended-response questions on core material.

• One out of two extended response questions to be attempted by candidates.


• The use of calculators is permitted. (See calculator section on the OCC.)

Paper 3Duration: 1 hourWeighting: 20%Marks: 35• This paper will have questions on core and SL option material.

• Section A: candidates answer all questions, two to three short-answer questions based on experimental skills and techniques, analysis and evaluation, using unseen data linked to the core material.

• Section B: short-answer and extended-response questions from one option.



External assessment

Biology guide 147

External assessment details—HL

Paper 1Duration: 1 hourWeighting: 20%Marks: 40• 40 multiple-choice questions on core and AHL material, about 15 of which are common with SL.


• The use of calculators is not permitted.

• No marks are deducted for incorrect answers.

Paper 2Duration: 2¼ hoursWeighting: 36%Marks: 72• Data-based question.

• Short-answer and extended-response questions on core and AHL material.

• Two out of three extended response questions to be attempted by candidates.



Paper 3Duration: 1¼ hoursWeighting: 24%Marks: 45• Section A: candidates answer all questions, two to three short-answer questions based on experimental

skills and techniques, analysis and evaluation, using unseen data linked to the core and AHL material.

• Section B: short-answer and extended-response questions from one option.



Biology guide148148

Assessment

Internal assessment

Purpose of internal assessmentInternal assessment is an integral part of the course and is compulsory for both SL and HL students. It enables students to demonstrate the application of their skills and knowledge, and to pursue their personal interests, without the time limitations and other constraints that are associated with written examinations. The internal assessment should, as far as possible, be woven into normal classroom teaching and not be a separate activity conducted after a course has been taught.

The internal assessment requirements at SL and at HL are the same. This internal assessment section of the guide should be read in conjunction with the internal assessment section of the teacher support materials.

Guidance and authenticityThe work submitted for internal assessment must be the student’s own work. However, it is not the intention that students should decide upon a title or topic and be left to work on the internal assessment component without any further support from the teacher. The teacher should play an important role during both the planning stage and the period when the student is working on the internally assessed work. It is the responsibility of the teacher to ensure that students are familiar with:

• the requirements of the type of work to be internally assessed

• the IB animal experimentation policy and the biology course safety guidelines

• the assessment criteria—students must understand that the work submitted for assessment must address these criteria effectively.

Teachers and students must discuss the internally assessed work. Students should be encouraged to initiate discussions with the teacher to obtain advice and information, and students must not be penalized for seeking guidance. As part of the learning process, teachers should read and give advice to students on one draft of the work. The teacher should provide oral or written advice on how the work could be improved, but not edit the draft. The next version handed to the teacher must be the final version for submission.

It is the responsibility of teachers to ensure that all students understand the basic meaning and significance of concepts that relate to academic honesty, especially authenticity and intellectual property. Teachers must ensure that all student work for assessment is prepared according to the requirements and must explain clearly to students that the internally assessed work must be entirely their own. Where collaboration between students is permitted, it must be clear to all students what the difference is between collaboration and collusion.

All work submitted to the IB for moderation or assessment must be authenticated by a teacher, and must not include any known instances of suspected or confirmed academic misconduct. Each student must confirm that the work is his or her authentic work and constitutes the final version of that work. Once a student has officially submitted the final version of the work it cannot be retracted. The requirement to confirm the authenticity of work applies to the work of all students, not just the sample work that will be submitted to the IB for the purpose of moderation. For further details refer to the IB publication Academic honesty (2011), The Diploma Programme: From principles into practice (2009) and the relevant articles in General regulations: Diploma Programme (2011).

Internal assessment

Biology guide 149

Authenticity may be checked by discussion with the student on the content of the work, and scrutiny of one or more of the following:

• the student’s initial proposal

• the first draft of the written work

• the references cited

• the style of writing compared with work known to be that of the student

• the analysis of the work by a web-based plagiarism detection service such as http://www.turnitin.com.

The same piece of work cannot be submitted to meet the requirements of both the internal assessment and the extended essay.

Group workEach investigation is an individual piece of work based on different data collected or measurements generated. Ideally, students should work on their own when collecting data. In some cases, data collected or measurements made can be from a group experiment provided each student collected his or her own data or made his or her own measurements. In biology, in some cases, group data or measurements may be combined to provide enough for individual analysis. Even in this case, each student should have collected and recorded their own data and they should clearly indicate which data are theirs.

It should be made clear to students that all work connected with the investigation should be their own. It is therefore helpful if teachers try to encourage in students a sense of responsibility for their own learning so that they accept a degree of ownership and take pride in their own work.

Time allocationInternal assessment is an integral part of the biology course, contributing 20% to the final assessment in the SL and the HL courses. This weighting should be reflected in the time that is allocated to teaching the knowledge, skills and understanding required to undertake the work, as well as the total time allocated to carry out the work.

It is recommended that a total of approximately 10 hours of teaching time for both SL and HL should be allocated to the work. This should include:

• time for the teacher to explain to students the requirements of the internal assessment

• class time for students to work on the internal assessment component and ask questions

• time for consultation between the teacher and each student

• time to review and monitor progress, and to check authenticity.

Safety requirements and recommendationsWhile teachers are responsible for following national or local guidelines, which may differ from country to country, attention should be given to the guidelines below, which were developed for the International Council of Associations for Science Education (ICASE) Safety Committee by The Laboratory Safety Institute (LSI).

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It is a basic responsibility of everyone involved to make safety and health an ongoing commitment. Any advice given will acknowledge the need to respect the local context, the varying educational and cultural traditions, the financial constraints and the legal systems of differing countries.

The Laboratory Safety Institute’s Laboratory Safety Guidelines...40 suggestions for a safer lab

Steps Requiring Minimal Expense1. Have a written health, safety and environmental affairs (HS&E) policy statement.

2. Organize a departmental HS&E committee of employees, management, faculty, staff and students that will meet regularly to discuss HS&E issues.

3. Develop an HS&E orientation for all new employees and students.

4. Encourage employees and students to care about their health and safety and that of others.

5. Involve every employee and student in some aspect of the safety program and give each specific responsibilities.

6. Provide incentives to employees and students for safety performance.

7. Require all employees to read the appropriate safety manual. Require students to read the institution’s laboratory safety rules. Have both groups sign a statement that they have done so, understand the contents, and agree to follow the procedures and practices. Keep these statements on file in the department office

8. Conduct periodic, unannounced laboratory inspections to identify and correct hazardous conditions and unsafe practices. Involve students and employees in simulated OSHA inspections.

9. Make learning how to be safe an integral and important part of science education, your work, and your life.

10. Schedule regular departmental safety meetings for all students and employees to discuss the results of inspections and aspects of laboratory safety.

11. When conducting experiments with hazards or potential hazards, ask yourself these questions:

– What are the hazards?

– What are the worst possible things that could go wrong?

– How will I deal with them?

– What are the prudent practices, protective facilities and equipment necessary to minimize the risk of exposure to the hazards?

12. Require that all accidents (incidents) be reported, evaluated by the departmental safety committee, and discussed at departmental safety meetings.

13. Require every pre-lab/pre-experiment discussion to include consideration of the health and safety aspects.

14. Don’t allow experiments to run unattended unless they are failsafe.

15. Forbid working alone in any laboratory and working without prior knowledge of a staff member.

16. Extend the safety program beyond the laboratory to the automobile and the home.

17. Allow only minimum amounts of flammable liquids in each laboratory.

18. Forbid smoking, eating and drinking in the laboratory.

19. Do not allow food to be stored in chemical refrigerators.

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20. Develop plans and conduct drills for dealing with emergencies such as fire, explosion, poisoning, chemical spill or vapour release, electric shock, bleeding and personal contamination.

21. Require good housekeeping practices in all work areas.

22. Display the phone numbers of the fire department, police department, and local ambulance either on or immediately next to every phone.

23. Store acids and bases separately. Store fuels and oxidizers separately.

24. Maintain a chemical inventory to avoid purchasing unnecessary quantities of chemicals.

25. Use warning signs to designate particular hazards.

26. Develop specific work practices for individual experiments, such as those that should be conducted only in a ventilated hood or involve particularly hazardous materials. When possible most hazardous experiments should be done in a hood.

Steps Requiring Moderate Expense27. Allocate a portion of the departmental budget to safety.

28. Require the use of appropriate eye protection at all times in laboratories and areas where chemicals are transported.

29. Provide adequate supplies of personal protective equipment—safety glasses, goggles, face shields, gloves, lab coats and bench top shields.

30. Provide fire extinguishers, safety showers, eye wash fountains, first aid kits, fire blankets and fume hoods in each laboratory and test or check monthly.

31. Provide guards on all vacuum pumps and secure all compressed gas cylinders.

32. Provide an appropriate supply of first aid equipment and instruction on its proper use.

33. Provide fireproof cabinets for storage of flammable chemicals.

34. Maintain a centrally located departmental safety library:

– “Safety in School Science Labs”, Clair Wood, 1994, Kaufman & Associates, 101 Oak Street, Wellesley, MA 02482

– “The Laboratory Safety Pocket Guide”, 1996, Genium Publisher, One Genium Plaza, Schnectady, NY

– “Safety in Academic Chemistry Laboratories”, ACS, 1155 Sixteenth Street NW, Washington, DC 20036

– “Manual of Safety and Health Hazards in The School Science Laboratory”, “Safety in the School Science Laboratory”, “School Science Laboratories: A guide to Some Hazardous Substances” Council of State Science Supervisors (now available only from LSI.)

– “Handbook of Laboratory Safety”, 4th Edition, CRC Press, 2000 Corporate Boulevard NW, Boca Raton, FL 33431

– “Fire Protection Guide on Hazardous Materials”, National Fire Protection Association, Batterymarch Park, Quincy, MA 02269

– “Prudent Practices in the Laboratory: Handling and Disposal of Hazardous Chemicals”, 2nd Edition, 1995

– “Biosafety in the Laboratory”, National Academy Press, 2101 Constitution Avenue, NW, Washington, DC 20418

– “Learning By Accident”, Volumes 1-3, 1997-2000, The Laboratory Safety Institute, Natick, MA 01760

(All are available from LSI.)

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35. Remove all electrical connections from inside chemical refrigerators and require magnetic closures.

36. Require grounded plugs on all electrical equipment and install ground fault interrupters (GFIs) where appropriate.

37. Label all chemicals to show the name of the material, the nature and degree of hazard, the appropriate precautions, and the name of the person responsible for the container.

38. Develop a program for dating stored chemicals and for recertifying or discarding them after predetermined maximum periods of storage.

39. Develop a system for the legal, safe and ecologically acceptable disposal of chemical wastes.

40. Provide secure, adequately spaced, well ventilated storage of chemicals.

Using assessment criteria for internal assessmentFor internal assessment, a number of assessment criteria have been identified. Each assessment criterion has level descriptors describing specific achievement levels, together with an appropriate range of marks. The level descriptors concentrate on positive achievement, although for the lower levels failure to achieve may be included in the description.

Teachers must judge the internally assessed work at SL and at HL against the criteria using the level descriptors.

• Assessment criteria are the same for both SL and HL.

• The aim is to find, for each criterion, the descriptor that conveys most accurately the level attained by the student, using the best-fit model. A best-fit approach means that compensation should be made when a piece of work matches different aspects of a criterion at different levels. The mark awarded should be one that most fairly reflects the balance of achievement against the criterion. It is not necessary for every single aspect of a level descriptor to be met for that mark to be awarded.

• When assessing a student’s work, teachers should read the level descriptors for each criterion until they reach a descriptor that most appropriately describes the level of the work being assessed. If a piece of work seems to fall between two descriptors, both descriptors should be read again and the one that more appropriately describes the student’s work should be chosen.

• Where there are two or more marks available within a level, teachers should award the upper marks if the student’s work demonstrates the qualities described to a great extent; the work may be close to achieving marks in the level above. Teachers should award the lower marks if the student’s work demonstrates the qualities described to a lesser extent; the work may be close to achieving marks in the level below.

• Only whole numbers should be recorded; partial marks (fractions and decimals) are not acceptable.

• Teachers should not think in terms of a pass or fail boundary, but should concentrate on identifying the appropriate descriptor for each assessment criterion.

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• The highest level descriptors do not imply faultless performance but should be achievable by a student. Teachers should not hesitate to use the extremes if they are appropriate descriptions of the work being assessed.

• A student who attains a high achievement level in relation to one criterion will not necessarily attain high achievement levels in relation to the other criteria. Similarly, a student who attains a low achievement level for one criterion will not necessarily attain low achievement levels for the other criteria. Teachers should not assume that the overall assessment of the students will produce any particular distribution of marks.

• It is recommended that the assessment criteria be made available to students.


General introductionThe internal assessment requirements are the same for biology, chemistry and physics. The internal assessment, worth 20% of the final assessment, consists of one scientific investigation. The individual investigation should cover a topic that is commensurate with the level of the course of study.

Student work is internally assessed by the teacher and externally moderated by the IB. The performance in internal assessment at both SL and HL is marked against common assessment criteria, with a total mark out of 24.

Note: Any investigation that is to be used to assess students should be specifically designed to match the relevant assessment criteria.

The internal assessment task will be one scientific investigation taking about 10 hours and the write-up should be about 6 to 12 pages long. Investigations exceeding this length will be penalized in the communication criterion as lacking in conciseness.

The practical investigation, with generic criteria, will allow a wide range of practical activities satisfying the varying needs of biology, chemistry and physics. The investigation addresses many of the learner profile attributes well. See section on “Approaches to teaching and learning” for further links.

The task produced should be complex and commensurate with the level of the course. It should require a purposeful research question and the scientific rationale for it. The marked exemplar material in the teacher support material will demonstrate that the assessment will be rigorous and of the same standard as the assessment in the previous courses.

Some of the possible tasks include:

• a hands-on laboratory investigation

• using a spreadsheet for analysis and modelling

• extracting data from a database and analysing it graphically

• producing a hybrid of spreadsheet/database work with a traditional hands-on investigation

• using a simulation provided it is interactive and open-ended.

Some tasks may consist of relevant and appropriate qualitative work combined with quantitative work.

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The tasks include the traditional hands-on practical investigations as in the previous course. The depth of treatment required for hands-on practical investigations is unchanged from the previous internal assessment and will be shown in detail in the teacher support materials. In addition, detailed assessment of specific aspects of hands-on practical work will be assessed in the written papers as detailed in the relevant topic(s) in the “Syllabus content” section of the guide.

The task will have the same assessment criteria for SL and HL. The five assessment criteria are personal engagement, exploration, analysis, evaluation and communication.

Internal assessment details

Internal assessment componentDuration: 10 hoursWeighting: 20%• Individual investigation.

• This investigation covers assessment objectives 1, 2, 3 and 4.

Internal assessment criteriaThe new assessment model uses five criteria to assess the final report of the individual investigation with the following raw marks and weightings assigned:

Personal engagement

Exploration Analysis Evaluation Communication Total

2 (8%) 6 (25%) 6 (25%) 6 (25%) 4 (17%) 24 (100%)

Levels of performance are described using multiple indicators per level. In many cases the indicators occur together in a specific level, but not always. Also, not all indicators are always present. This means that a candidate can demonstrate performances that fit into different levels. To accommodate this, the IB assessment models use markbands and advise examiners and teachers to use a best-fit approach in deciding the appropriate mark for a particular criterion.

Teachers should read the guidance on using markbands shown above in the section called “Using assessment criteria for internal assessment” before starting to mark. It is also essential to be fully acquainted with the marking of the exemplars in the teacher support material. The precise meaning of the command terms used in the criteria can be found in the glossary of the subject guides.

Personal engagementThis criterion assesses the extent to which the student engages with the exploration and makes it their own. Personal engagement may be recognized in different attributes and skills. These could include addressing personal interests or showing evidence of independent thinking, creativity or initiative in the designing, implementation or presentation of the investigation.

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Mark Descriptor

0 The student’s report does not reach a standard described by the descriptors below.

1 The evidence of personal engagement with the exploration is limited with little independent thinking, initiative or creativity.

The justification given for choosing the research question and/or the topic under investigation does not demonstrate personal significance, interest or curiosity.

There is little evidence of personal input and initiative in the designing, implementation or presentation of the investigation.

2 The evidence of personal engagement with the exploration is clear with significant independent thinking, initiative or creativity.

The justification given for choosing the research question and/or the topic under investigation demonstrates personal significance, interest or curiosity.

There is evidence of personal input and initiative in the designing, implementation or presentation of the investigation.

Exploration This criterion assesses the extent to which the student establishes the scientific context for the work, states a clear and focused research question and uses concepts and techniques appropriate to the Diploma Programme level. Where appropriate, this criterion also assesses awareness of safety, environmental, and ethical considerations.

Mark Descriptor


1–2 The topic of the investigation is identified and a research question of some relevance is stated but it is not focused.

The background information provided for the investigation is superficial or of limited relevance and does not aid the understanding of the context of the investigation.

The methodology of the investigation is only appropriate to address the research question to a very limited extent since it takes into consideration few of the significant factors that may influence the relevance, reliability and sufficiency of the collected data.

The report shows evidence of limited awareness of the significant safety, ethical or environmental issues that are relevant to the methodology of the investigation*.

3–4 The topic of the investigation is identified and a relevant but not fully focused research question is described.

The background information provided for the investigation is mainly appropriate and relevant and aids the understanding of the context of the investigation.

The methodology of the investigation is mainly appropriate to address the research question but has limitations since it takes into consideration only some of the significant factors that may influence the relevance, reliability and sufficiency of the collected data.

The report shows evidence of some awareness of the significant safety, ethical or environmental issues that are relevant to the methodology of the investigation*.

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Mark Descriptor

5–6 The topic of the investigation is identified and a relevant and fully focused research question is clearly described.

The background information provided for the investigation is entirely appropriate and relevant and enhances the understanding of the context of the investigation.

The methodology of the investigation is highly appropriate to address the research question because it takes into consideration all, or nearly all, of the significant factors that may influence the relevance, reliability and sufficiency of the collected data.

The report shows evidence of full awareness of the significant safety, ethical or environmental issues that are relevant to the methodology of the investigation*.

* This indicator should only be applied when appropriate to the investigation. See exemplars in TSM.

AnalysisThis criterion assesses the extent to which the student’s report provides evidence that the student has selected, recorded, processed and interpreted the data in ways that are relevant to the research question and can support a conclusion.

Mark Descriptor


1–2 The report includes insufficient relevant raw data to support a valid conclusion to the research question.

Some basic data processing is carried out but is either too inaccurate or too insufficient to lead to a valid conclusion.

The report shows evidence of little consideration of the impact of measurement uncertainty on the analysis.

The processed data is incorrectly or insufficiently interpreted so that the conclusion is invalid or very incomplete.

3–4 The report includes relevant but incomplete quantitative and qualitative raw data that could support a simple or partially valid conclusion to the research question.

Appropriate and sufficient data processing is carried out that could lead to a broadly valid conclusion but there are significant inaccuracies and inconsistencies in the processing.

The report shows evidence of some consideration of the impact of measurement uncertainty on the analysis.

The processed data is interpreted so that a broadly valid but incomplete or limited conclusion to the research question can be deduced.

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Mark Descriptor

5–6 The report includes sufficient relevant quantitative and qualitative raw data that could support a detailed and valid conclusion to the research question.

Appropriate and sufficient data processing is carried out with the accuracy required to enable a conclusion to the research question to be drawn that is fully consistent with the experimental data.

The report shows evidence of full and appropriate consideration of the impact of measurement uncertainty on the analysis.

The processed data is correctly interpreted so that a completely valid and detailed conclusion to the research question can be deduced.

Evaluation This criterion assesses the extent to which the student’s report provides evidence of evaluation of the investigation and the results with regard to the research question and the accepted scientific context.

Mark Descriptor


1–2 A conclusion is outlined which is not relevant to the research question or is not supported by the data presented.

The conclusion makes superficial comparison to the accepted scientific context.

Strengths and weaknesses of the investigation, such as limitations of the data and sources of error, are outlined but are restricted to an account of the practical or procedural issues faced.

The student has outlined very few realistic and relevant suggestions for the improvement and extension of the investigation.

3–4 A conclusion is described which is relevant to the research question and supported by the data presented.

A conclusion is described which makes some relevant comparison to the accepted scientific context.

Strengths and weaknesses of the investigation, such as limitations of the data and sources of error, are described and provide evidence of some awareness of the methodological issues* involved in establishing the conclusion.

The student has described some realistic and relevant suggestions for the improvement and extension of the investigation.

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Mark Descriptor

5–6 A detailed conclusion is described and justified which is entirely relevant to the research question and fully supported by the data presented.

A conclusion is correctly described and justified through relevant comparison to the accepted scientific context.

Strengths and weaknesses of the investigation, such as limitations of the data and sources of error, are discussed and provide evidence of a clear understanding of the methodological issues* involved in establishing the conclusion.

The student has discussed realistic and relevant suggestions for the improvement and extension of the investigation.

*See exemplars in TSM for clarification.

CommunicationThis criterion assesses whether the investigation is presented and reported in a way that supports effective communication of the focus, process and outcomes.

Mark Descriptor


1–2 The presentation of the investigation is unclear, making it difficult to understand the focus, process and outcomes.

The report is not well structured and is unclear: the necessary information on focus, process and outcomes is missing or is presented in an incoherent or disorganized way.

The understanding of the focus, process and outcomes of the investigation is obscured by the presence of inappropriate or irrelevant information.

There are many errors in the use of subject-specific terminology and conventions*.

3–4 The presentation of the investigation is clear. Any errors do not hamper understanding of the focus, process and outcomes.

The report is well structured and clear: the necessary information on focus, process and outcomes is present and presented in a coherent way.

The report is relevant and concise thereby facilitating a ready understanding of the focus, process and outcomes of the investigation.

The use of subject-specific terminology and conventions is appropriate and correct. Any errors do not hamper understanding.

*For example, incorrect/missing labelling of graphs, tables, images; use of units, decimal places. For issues of referencing and citations refer to the “Academic honesty” section.

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Rationale for practical workAlthough the requirements for IA are centred on the investigation, the different types of practical activities that a student may engage in serve other purposes, including:

• illustrating, teaching and reinforcing theoretical concepts

• developing an appreciation of the essential hands-on nature of much scientific work

• developing an appreciation of scientists’ use of secondary data from databases

• developing an appreciation of scientists’ use of modelling

• developing an appreciation of the benefits and limitations of scientific methodology.

Practical scheme of workThe practical scheme of work (PSOW) is the practical course planned by the teacher and acts as a summary of all the investigative activities carried out by a student. Students at SL and HL in the same subject may carry out some of the same investigations.

Syllabus coverageThe range of practical work carried out should reflect the breadth and depth of the subject syllabus at each level, but it is not necessary to carry out an investigation for every syllabus topic. However, all students must participate in the group 4 project and the IA investigation.

Planning your practical scheme of workTeachers are free to formulate their own practical schemes of work by choosing practical activities according to the requirements outlined. Their choices should be based on:

• subjects, levels and options taught

• the needs of their students

• available resources

• teaching styles.

Each scheme must include some complex experiments that make greater conceptual demands on students. A scheme made up entirely of simple experiments, such as ticking boxes or exercises involving filling in tables, will not provide an adequate range of experience for students.

Teachers are encouraged to use the online curriculum centre (OCC) to share ideas about possible practical activities by joining in the discussion forums and adding resources in the subject home pages.

FlexibilityThe practical programme is flexible enough to allow a wide variety of practical activities to be carried out. These could include:

• short labs or projects extending over several weeks

• computer simulations

• using databases for secondary data

• developing and using models

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• data-gathering exercises such as questionnaires, user trials and surveys

• data-analysis exercises

• fieldwork.

Practical work documentationDetails of the practical scheme of work are recorded on Form 4/PSOW provided in the Handbook of Procedures. A copy of the class 4/PSOW form must be included with any sample set sent for moderation. For an SL only class or an HL only class, only one 4/PSOW is required, but for a mixed SL/HL class, separate 4/PSOW forms are required for SL and HL.

Time allocation for practical workThe recommended teaching times for all Diploma Programme courses are 150 hours at SL and 240 hours at HL. Students at SL are required to spend 40 hours, and students at HL 60 hours, on practical activities (excluding time spent writing up work). These times include 10 hours for the group 4 project and 10 hours for the internal assessment investigation. (Only 2–3 hours of investigative work can be carried out after the deadline for submitting work to the moderator and still be counted in the total number of hours for the practical scheme of work.)

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Assessment

The group 4 project

The group 4 project is an interdisciplinary activity in which all Diploma Programme science students must participate. The intention is that students from the different group 4 subjects analyse a common topic or problem. The exercise should be a collaborative experience where the emphasis is on the processes involved in, rather than the products of, such an activity.

In most cases students in a school would be involved in the investigation of the same topic. Where there are large numbers of students, it is possible to divide them into several smaller groups containing representatives from each of the science subjects. Each group may investigate the same topic or different topics—that is, there may be several group 4 projects in the same school.

Students studying environmental systems and societies are not required to undertake the group 4 project.

Summary of the group 4 projectThe group 4 project is a collaborative activity where students from different group 4 subjects work together on a scientific or technological topic, allowing for concepts and perceptions from across the disciplines to be shared in line with aim 10—that is, to “develop an understanding of the relationships between scientific disciplines and their influence on other areas of knowledge”. The project can be practically or theoretically based. Collaboration between schools in different regions is encouraged.

The group 4 project allows students to appreciate the environmental, social and ethical implications of science and technology. It may also allow them to understand the limitations of scientific study, for example, the shortage of appropriate data and/or the lack of resources. The emphasis is on interdisciplinary cooperation and the processes involved in scientific investigation, rather than the products of such investigation.

The choice of scientific or technological topic is open but the project should clearly address aims 7, 8 and 10 of the group 4 subject guides.

Ideally, the project should involve students collaborating with those from other group 4 subjects at all stages. To this end, it is not necessary for the topic chosen to have clearly identifiable separate subject components. However, for logistical reasons, some schools may prefer a separate subject “action” phase (see the following “Project stages” section).

Project stagesThe 10 hours allocated to the group 4 project, which are part of the teaching time set aside for developing the practical scheme of work, can be divided into three stages: planning, action and evaluation.

PlanningThis stage is crucial to the whole exercise and should last about two hours.

• The planning stage could consist of a single session, or two or three shorter ones.

• This stage must involve all group 4 students meeting to “brainstorm” and discuss the central topic, sharing ideas and information.

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• The topic can be chosen by the students themselves or selected by the teachers.

• Where large numbers of students are involved, it may be advisable to have more than one mixed subject group.

After selecting a topic or issue, the activities to be carried out must be clearly defined before moving from the planning stage to the action and evaluation stages.

A possible strategy is that students define specific tasks for themselves, either individually or as members of groups, and investigate various aspects of the chosen topic. At this stage, if the project is to be experimentally based, apparatus should be specified so that there is no delay in carrying out the action stage. Contact with other schools, if a joint venture has been agreed, is an important consideration at this time.

ActionThis stage should last around six hours and may be carried out over one or two weeks in normal scheduled class time. Alternatively, a whole day could be set aside if, for example, the project involves fieldwork.

• Students should investigate the topic in mixed-subject groups or single subject groups.

• There should be collaboration during the action stage; findings of investigations should be shared with other students within the mixed/single-subject group. During this stage, in any practically based activity, it is important to pay attention to safety, ethical and environmental considerations.

Note: Students studying two group 4 subjects are not required to do two separate action phases.

EvaluationThe emphasis during this stage, for which two hours are probably necessary, is on students sharing their findings, both successes and failures, with other students. How this is achieved can be decided by the teachers, the students or jointly.

• One solution is to devote a morning, afternoon or evening to a symposium where all the students, as individuals or as groups, give brief presentations.

• Alternatively, the presentation could be more informal and take the form of a science fair where students circulate around displays summarizing the activities of each group.

The symposium or science fair could also be attended by parents, members of the school board and the press. This would be especially pertinent if some issue of local importance has been researched. Some of the findings might influence the way the school interacts with its environment or local community.

Addressing aims 7 and 8Aim 7: “develop and apply 21st century communication skills in the study of science.”

Aim 7 may be partly addressed at the planning stage by using electronic communication within and between schools. It may be that technology (for example, data logging, spreadsheets, databases and so on) will be used in the action phase and certainly in the presentation/evaluation stage (for example, use of digital images, presentation software, websites, digital video and so on).

Aim 8: “become critically aware, as global citizens, of the ethical implications of using science and technology.”

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Addressing the international dimensionThere are also possibilities in the choice of topic to illustrate the international nature of the scientific endeavour and the increasing cooperation required to tackle global issues involving science and technology. An alternative way to bring an international dimension to the project is to collaborate with a school in another region.

Types of projectWhile addressing aims 7, 8 and 10 the project must be based on science or its applications. The project may have a hands-on practical action phase or one involving purely theoretical aspects. It could be undertaken in a wide range of ways:

• designing and carrying out a laboratory investigation or fieldwork.

• carrying out a comparative study (experimental or otherwise) in collaboration with another school.

• collating, manipulating and analysing data from other sources, such as scientif ic journals, environmental organizations, science and technology industries and government reports.

• designing and using a model or simulation.

• contributing to a long-term project organized by the school.

Logistical strategiesThe logistical organization of the group 4 project is often a challenge to schools. The following models illustrate possible ways in which the project may be implemented.

Models A, B and C apply within a single school, and model D relates to a project involving collaboration between schools.

Model A: mixed-subject groups and one topic

Schools may adopt mixed-subject groups and choose one common topic. The number of groups will depend on the number of students.

Model B: mixed-subject groups adopting more than one topic

Schools with large numbers of students may choose to do more than one topic.

Model C: single-subject groups

For logistical reasons some schools may opt for single subject groups, with one or more topics in the action phase. This model is less desirable as it does not show the mixed subject collaboration in which many scientists are involved.

Model D: collaboration with another school

The collaborative model is open to any school. To this end, the IB provides an electronic collaboration board on the OCC where schools can post their project ideas and invite collaboration from other schools. This could range from merely sharing evaluations for a common topic to a full-scale collaborative venture at all stages.

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For schools with few Diploma Programme students or schools with Diploma Programme course students, it is possible to work with non-Diploma Programme or non-group 4 students or undertake the project once every two years. However, these schools are encouraged to collaborate with another school. This strategy is also recommended for individual students who may not have participated in the project, for example, through illness or because they have transferred to a new school where the project has already taken place.

TimingThe 10 hours that the IB recommends be allocated to the project may be spread over a number of weeks. The distribution of these hours needs to be taken into account when selecting the optimum time to carry out the project. However, it is possible for a group to dedicate a period of time exclusively to project work if all/most other schoolwork is suspended.

Year 1In the first year, students’ experience and skills may be limited and it would be inadvisable to start the project too soon in the course. However, doing the project in the final part of the first year may have the advantage of reducing pressure on students later on. This strategy provides time for solving unexpected problems.

Year 1–Year 2The planning stage could start, the topic could be decided upon, and provisional discussion in individual subjects could take place at the end of the first year. Students could then use the vacation time to think about how they are going to tackle the project and would be ready to start work early in the second year.

Year 2Delaying the start of the project until some point in the second year, particularly if left too late, increases pressure on students in many ways: the schedule for finishing the work is much tighter than for the other options; the illness of any student or unexpected problems will present extra difficulties. Nevertheless, this choice does mean students know one another and their teachers by this time, have probably become accustomed to working in a team and will be more experienced in the relevant fields than in the first year.

Combined SL and HLWhere circumstances dictate that the project is only carried out every two years, HL beginners and more experienced SL students can be combined.

Selecting a topicStudents may choose the topic or propose possible topics and the teacher then decides which one is the most viable based on resources, staff availability and so on. Alternatively, the teacher selects the topic or proposes several topics from which students make a choice.

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Student selectionStudents are likely to display more enthusiasm and feel a greater sense of ownership for a topic that they have chosen themselves. A possible strategy for student selection of a topic, which also includes part of the planning stage, is outlined here. At this point, subject teachers may provide advice on the viability of proposed topics.

• Identify possible topics by using a questionnaire or a survey of students.

• Conduct an initial “brainstorming” session of potential topics or issues.

• Discuss, briefly, two or three topics that seem interesting.

• Select one topic by consensus.

• Students make a list of potential investigations that could be carried out. All students then discuss issues such as possible overlap and collaborative investigations.

A reflective statement written by each student on their involvement in the group 4 project must be included on the coversheet for each internal assessment investigation. See Handbook of Procedures for more details.

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Appendices

Glossary of command terms

Command terms with definitionsStudents should be familiar with the following key terms and phrases used in examination questions. Although these terms will be used frequently in examination questions, other terms may be used to direct students to present an argument in a specific way.

These command terms indicate the depth of treatment required.

Assessment objective 1Define Give the precise meaning of a word, phrase, concept or physical quantity.

Draw Represent by means of a labelled, accurate diagram or graph, using a pencil. A ruler (straight edge) should be used for straight lines. Diagrams should be drawn to scale. Graphs should have points correctly plotted (if appropriate) and joined in a straight line or smooth curve.

Label Add labels to a diagram.

List Give a sequence of brief answers with no explanation.

Measure Obtain a value for a quantity.

State Give a specific name, value or other brief answer without explanation or calculation.

Assessment objective 2Annotate Add brief notes to a diagram or graph.

Calculate Obtain a numerical answer showing the relevant stages in the working (unless instructed not to do so).

Describe Give a detailed account.

Distinguish Make clear the differences between two or more concepts or items.

Estimate Obtain an approximate value.

Identify Provide an answer from a number of possibilities.

Outline Give a brief account or summary.

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Assessment objective 3Analyse Break down in order to bring out the essential elements or structure.

Comment Give a judgment based on a given statement or result of a calculation.

Compare Give an account of the similarities between two (or more) items or situations, referring to both (all) of them throughout.

Compare and contrast

Give an account of similarities and differences between two (or more) items or situations, referring to both (all) of them throughout.

Construct Display information in a diagrammatic or logical form.

Deduce Reach a conclusion from the information given.

Design Produce a plan, simulation or model.

Determine Obtain the only possible answer.

Discuss Offer a considered and balanced review that includes a range of arguments, factors or hypotheses. Opinions or conclusions should be presented clearly and supported by appropriate evidence.

Evaluate Make an appraisal by weighing up the strengths and limitations.

Explain Give a detailed account including reasons or causes.

Predict Give an expected result.

Sketch Represent by means of a diagram or graph (labelled as appropriate). The sketch should give a general idea of the required shape or relationship, and should include relevant features.

Suggest Propose a solution, hypothesis or other possible answer.

Biology guide168168

Appendices

Bibliography

This bibliography lists the principal works used to inform the curriculum review. It is not an exhaustive list and does not include all the literature available: judicious selection was made in order to better advise and guide teachers. This bibliography is not a list of recommended textbooks.

Rhoton, J. 2010. Science Education Leadership: Best Practices for the New Century. Arlington, Virginia, USA. National Science Teachers Association Press.

Masood, E. 2009. Science & Islam: A History. London, UK. Icon Books.

Roberts, B. 2009. Educating for Global Citizenship: A Practical Guide for Schools. Cardiff, UK. International Baccalaureate Organization.

Martin, J. 2006. The Meaning of the 21st Century: A vital blueprint for ensuring our future. London, UK. Eden Project Books.

Gerzon, M. 2010. Global Citizens: How our vision of the world is outdated, and what we can do about it. London, UK. Rider Books.

Haydon, G. 2006. Education, Philosophy & the Ethical Environment. Oxon/New York, USA. Routledge.

Anderson, LW et al. 2001. A Taxonomy for Learning, Teaching, and Assessing: A Revision of Bloom’s Taxonomy of Educational Objectives. New York, USA. Addison Wesley Longman, Inc.

Hattie, J. 2009. Visible learning: A synthesis of over 800 meta-analyses relating to achievement. Oxon/New York, USA. Routledge.

Petty, G. 2009. Evidence-based Teaching: A practical approach (2nd edition). Cheltenham, UK. Nelson Thornes Ltd.

Andain, I and Murphy, G. 2008. Creating Lifelong Learners: Challenges for Education in the 21st Century. Cardiff, UK. International Baccalaureate Organization.

Jewkes, J, Sawers, D and Stillerman, R. 1969. The Sources of Invention (2nd edition). New York, USA. W.W. Norton & Co.

Lawson, B. 2005. How Designers Think: The design process demystified (4th edition). Oxford, UK. Architectural Press.

Douglas, H. 2009. Science, Policy, and the Value-Free Ideal. Pittsburgh, Pennsylvania, USA. University of Pittsburgh Press.

Aikenhead, G and Michell, H. 2011. Bridging Cultures: Indigenous and Scientific Ways of Knowing Nature. Toronto, Canada. Pearson Canada.

Winston, M and Edelbach, R. 2012. Society, Ethics, and Technology (4th edition). Boston, Massachusetts, USA. Wadsworth CENGAGE Learning.

Brian Arthur, W. 2009. The Nature of Technology. London, UK. Penguin Books.

Headrick, D. 2009. Technology: A World History. Oxford, UK. Oxford University Press.

Bibliography

Biology guide 169

Popper, KR. 1980. The Logic of Scientific Discovery (4th revised edition). London, UK. Hutchinson.

Trefil, J. 2008. Why Science?. New York/Arlington, USA. NSTA Press & Teachers College Press.

Kuhn, T. S. 1996. The Structure of Scientific Revolutions (3rd edition). Chicago, Illinois, USA. The University of Chicago Press.

Khine, MS, (ed). 2012. Advances in Nature of Science Research: Concepts and Methodologies. Bahrain. Springer.

Spier, F. 2010. Big History and the Future of Humanity. Chichester, UK. Wiley-Blackwell.

Stokes Brown, C. 2007. Big History: From the Big Bang to the Present. New York, USA. The New Press.

Swain, H, (ed). 2002. Big Questions in Sciences. London, UK. Vintage.

Roberts, RM. 1989. Serendipity: Accidental Discoveries in Science. Chichester, UK. Wiley Science Editions.

Ehrlich, R. 2001. Nine crazy ideas in science. Princeton, New Jersey, USA. Princeton University Press.

Lloyd, C. 2012. What on Earth Happened?: The Complete Story of the Planet, Life and People from the Big Bang to the Present Day. London, UK. Bloomsbury Publishing.

Trefil, J and Hazen, RM. 2010. Sciences: An integrated Approach (6th edition). Chichester, UK. Wiley.

ICASE. 2010. Innovation in Science & Technology Education: Research, Policy, Practice. Tartu, Estonia. ICASE/UNESCO/University of Tartu.

American Association for the Advancement of Science. 1990. Science for all Americans online. Washington, USA. http://www.project2061.org/publications/sfaa/online/sfaatoc.htm.

The Geological Society of America. 2012. Nature of Science and the Scientific Method. Boulder, Colorado, USA. http://www.geosociety.org/educate/naturescience.pdf.

Big History Project. 2011. Big History: An Introduction to Everything. http://www.bighistoryproject.com.

Nuffield Foundation. 2012. How science works. London, UK. http://www.nuffieldfoundation.org/practical-physics/how-science-works.

University of California Museum of Paleontology. 2013. Understanding Science. Berkeley, California, USA. 1 February 2013. http://www.understandingscience.org.

Collins, S, Osborne, J, Ratcliffe, M, Millar, R, and Duschl, R. 2012, What ‘ideas-about-science’ should be taught in school science? A Delphi study of the ‘expert’ community. St. Louis, Missouri, USA. National Association for Research in Science Teaching (NARST).

T I M S S ( T h e Tr e n d s i n I n t e r n a t i o n a l M a t h e m a t i c s a n d S c i e n c e S t u d y) . 1 F e b r u a r y 2 013 . http://timssandpirls.bc.edu.

PISA (Programme for International Student Assessment). 1 February 2013. http://www.oecd.org/pisa.

ROSE (The Relevance of Science Education). 1 February 2013. http://roseproject.no/.

Biology guide - IB Documents SUBJECT GUIDES/Group 4... · 2019-06-11 · Biology guide 5...

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