Revision10

Bio3B

Structure of the exam paperSection One - Multiple-choice – 20 questions – 40 marksAnswer all questions, using a blue or black pen, on the separate Multiple Choice Answer Sheet.Suggested working time 30 minutesSection Two - Short answers – 5 questions – 100 marksAnswer in the spaces provided in this Question/Answer Booklet. Do not answer this section in the Standard Answer Book. A blue or black ball point or ink pen should be used for written answers and pencil for diagrams.Suggested working time 90 minutesSection Three - Extended answers Part A – select 2 questions from a choice of 4 – 30 marks (15 marks each)Part B – select 2 questions from a choice of 4 – 30 marks (15 marks each)Write your answers in the Standard Answers Book. Your writing or printing must be LEGIBLE. Use a blue or black ball point or ink pen for this section.Answers may be presented in a combination of different ways provided they communicate your ideas

effectively. You may choose to:• present a clearly labelled diagram or flow chart;• write notes besides a clear diagram;• write lists of points, with sentences which link them;• write concisely worded sentences;• use some other appropriate way to present ideas.Suggested working time 60 minutes (30 minutes for Part A and 30 minutes for Part B)Total marks 200

The mock exam and the WACE are on the whole year’s work (A and B)

Notes about exam format

The WACE Biology examination will be marked online. Students will write all of their responses for sections B and C in the

question/answer booklet. The following points will facilitate the on-line marking:1. Please write in blue or black ink, not pencil.2. If drawing diagrams in pencil, please press firmly to ensure a strong line.3. Avoid highlighters. The examiners’ reports discourage their use and they

will not show up in on- line marking.4. The only answer that the examiners will see in colour is the compulsory

graphing question in Section B, where some candidates use colour in the legend. It is unnecessary to use colour elsewhere.

5. Wherever possible, confine answers to the lined spaces provided in the answer book.

The mock exams are set up in exactly the same format as the WACE exams.

Non-programmable calculatorsThere is no limit on the number of non-programmable calculators permitted in

these examinations.An approved non-programmable calculator is any commercially produced

calculator which is battery or solar operated, silent, hand held, non-programmable and does not have either a full alphabetic display or a graphical display.

As a guide only, the following typically appear on programmable calculators- data bank - load- execute - memo- formulae - programme- forward- reverse- go to - run- learn - LRN- letters of the

alphabetWatches, rulers, pens or any other equipment with built-in calculators or

memory functions must also conform to the criteria for an approved calculator.

Extended answer format

Q26. You could answer this one

OR

Q27. You could do this one

OR

Q28. You could answer this one

OR

Q29. You could do this one

Indicate the second question you will answer on page 34 .Five ruled pages for the answer will be provided (pages 29-33). Then on page 34:Indicate the second question you will answer by ticking the box next to the question. Write your answer on the pages provided.Then you do the same for part B – ticking the box & answering each question on the pages indicated

Part AAnswer any two questions from questions 26 to 29. (30 marks)Indicate the first question you will answer by ticking the box next to the question. Write your answer on the pages provided.

Conservation

Over the last century, thousands of species have decreased in numbers, around the world. In WA alone over 20 species of small marsupials are threatened with extinction within the next decade.

a) Discuss reasons for the decrease in numbers of species.

b) Discuss the consequences of the permanent extinction of these and other native species.

c) Describe strategies that could be used to prevent the extinction of these and other species

ConservationOver the last century, thousands of species have decreased in numbers, around the

world. In WA alone over 20 species of small marsupials are threatened with extinction within the next decade.

a) Discuss reasons for the decrease in numbers of species.Habitat loss (agriculture, mining, logging, urbanisation)Pollution (eutrophication, pesticides/biomagnification, heavy metals)Environmental degradation (salinity, erosion, desertification) loss of habitatIntroduced species (competitors, predators, diseases, non-edible vegetation)Poaching/hunting

b) Discuss the consequences of the permanent extinction of these and other native species.

Loss of species raises the following questions:Aesthetic value of biodiversityEthics – is it right to destroy biodiversity?Custodial – we should preserve biodiversity for future generationsUtility – biodiversity may provide useful products (e.g. medicines)Ecosystem stability – biodiversity contributes to ecosystem servicesRecreation/ecotourismScientific researchEducationAffects ability to cope with environmental change/greater genetic diversity

ConservationOver the last century, thousands of species have decreased in numbers,

around the world. In WA alone over 20 species of small marsupials are threatened with extinction within the next decade.

c) Describe strategies that could be used to prevent the extinction of these and other species

Management strategies involve controlling access to and use of areas eg parks, reserves, limits on size or numbers of organisms to be taken

Environmental strategies involve maintaining habitats and controlling changes eg reafforestation, biological control, removal of introduced species

Genetic strategies involve manipulation of DNA or gene pools eg breeding programs, genetic engineering, DNA profiling, seed banks

Remember marks are often given for examples eg breeding programs and release of numbats, cloning of Tasmanian tigers etc

Protein synthesisName structures:

1

2

4

Indicate on the diagram the location of

• transcription

• translation

• the template strand

• DNA

• a codon

• an anticodon

• a protein

Protein synthesisName structures:

1 mRNA

2 tRNA

4 Ribosome

Indicate on the diagram the location of

• transcription

• translation

• the template strand

• DNA

• a codon

• an anticodon

• a protein

transcription

translation

DNA

codon

anticodon

protein

DNA replication and protein synthesis

Compare and contrast the processes of transcription, translation and DNA replication.

Include in your answer the:

Inputs

Outputs

Enzymes involved

Roles of RNA and DNA

Importance to the functioning of organisms

DNA replication and protein synthesisTranscription - copying of DNA to make RNA – 1st step in the

process of protein synthesis Uses the base pair rule

Cytosine in DNA Guanine in RNA Guanine in DNA Cytosine in RNAAdenine in DNA Uracil in RNA Thymine in DNA Adenine in RNA(RNA contains Uracil not Thymine)

DNA acts as template, mRNA is madeInputs – ribose nucleotides (A, C, U and G)Outputs – mRNAEnzymes – Helicase unwinds DNA, RNA polymerase glues

nucleotides together

Translation - reading of mRNA to make proteins – occurs at ribosomes – 2nd step in protein synthesis

Inputs – amino acids, tRNA (carries amino acids into ribosome), mRNA (codes for sequence), ribosome

Outputs – protein (ribosomes, mRNA & tRNA undamaged)Ribosomal enzymes attach amino acids togetherAnticodons on tRNA attach to codons on mRNA using base pair rule

DNA replication – duplication of DNA – necessary for cell division (reproduction or replacement of cells)Uses base pair rule A -T, C – GInputs – deoxyribose nucleotides (A, T, C and G)Outputs - new DNA strandsEnzymes - Helicase unwinds DNA, DNA polymerase glues nucleotides together, RNA primase makes primerRNA fragments act as primers to start the replication process

Using DNA technology

The diagram opposite shows the results of gel electrophoresis on members of a family.

One of the children is adopted.

a) Which child is it?

b) How can you tell?

One of the children is the result of a previous marriage of one of the parents.

a) Which child is it?

b) Who is the genetic parent & who is the step-parent?

c) How can you tell?

Using DNA technology

The diagram opposite shows the results of gel electrophoresis on members of a family.

One of the children is adopted.

a) Which child is it? S2

b) How can you tell? No genes in common

One of the children is the result of a previous marriage of one of the parents.

a) Which child is it? D2

b) Who is the genetic parent & who is the step-parent? Mother is gene dor, father is stepfather

c) How can you tell? Daughter shares genes with mother but not father

BiotechnologyDescribe how the following can be used in agriculture or conservation. Include

a description of each technique• DNA sequencing

• Gel electrophoresis

• PCR (polymerase chain reaction)

• Genetic probes

• Recombinant DNA techniques

• Cloning

• Tissue culture

• Transgenic organisms

DNA sequencingDNA sequencing involves identifying the

precise order of nucleotide in DNA. In DNA profiling sequences are

compared between individuals (DNA fingerprint or profile)

Special enzymes called restriction enzymes are use to split the DNA into segments so the sequence of nucleotides can be identified.

It is used to• identify the genetic relationships

between individuals (eg to confirm paternity)

• forensic science (eg identifying criminals)

• look for genetic disease

Gel electrophoresis

Gel electrophoresis refers to a process that allows identification or observation of DNA patterns

Uses include identification of

• individuals from samples (eg forensic science)

• genome sequences

• presence of inherited disease

Polymerase chain reaction

Polymerase chain reaction (PCR) refers to the process used to replicate DNA.

This increases the amount of DNA present in a sample.

It is needed so that there is enough DNA present to test.

Genetic probes

Probes are nucleic acid bases arranged in a sequence which is complementary to a sequence in the genome

They usually have radioactive or chemical markers that are used to make them easily visible

They can be used to detect if a genomic sequence is present, deleted or altered.

They are often used to identify the presence of a gene for a disease

Recombinant DNA technologyThis is also known as genetic engineeringThis refers to the processes that allow introduction of new

DNA into a cell. This allows the taking of genes from one organism and placing them in the chromosomes of another producing a transgenic organism.

The genes can come from individuals of the same species (eg transferring a healthy gene from one person into a person with a genetic disease = gene therapy) or from a different species (eg placing insulin producing gene into a bacteria)

Uses include gene therapy, producing transgenic bacteria that can produce useful products (eg insulin).

Products now being produced by this technology include hormones (eg insulin, hGH, FSH), factor VIII or vaccines

Recombinant DNA techniques

Restriction enzymes are used to cut sections of DNA at specific locations and are necessary because they allow the selection of 1 gene or DNA fragment

Ligation refers to joining of the two segments and is necessary because it produces 1 strand of DNA or a plasmid now containing the gene

A gene for antibiotic resistance is usually added so that the bacteria with the new DNA can be identified and collected

Gene cloning

In gene cloning the host cell's biochemical processes are used to make many copies of the inserted gene and the protein it codes for.

Cloning animals

The cloning of animals has many important commercial implications. It allows an individual animal with desirable features, such as a cow that produces

a lot of milk, to be duplicated several times. Mice have successfully been cloned from frozen tissue

Cloned mice provide identical test subjects for research

Tissue culture Tissue culture is the growth of

tissues and/or cells separate from the organism in a growth medium – this can be liquid or solid (eg on agar).

In plants this has been used for centuries for propagation.

In animals it is being used to grow tissues for research and medical treatments (eg skin grafts)

Another recent area of research is tissue culture to produce meat products, instead of raising animals to be killed for food – animal tissue will be grown in vats and harvested.

Transgenic organisms

These are organisms with inserted genes.

They are also known as genetically modified organisms or GMO’s.

Uses include inserting genes for:• pest or disease resistance eg cotton • turning off the gene for ripening to

give a longer shelf life eg tomatoes• ability to cope with salt or drought eg

wheat• add nutrients to food eg omega 3

fatty acids into vegetable• create cyanobacteria capable of

making ‘diesel’ fuel