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L.38

WARNING: This Question Paper MUST be returned with your answer book(s) at the end of the Examination: otherwise marks will be lost.

STUDENT NAME

SCHOOL

TEACHER

PRE-LEAVING CERTIFICATE EXAMINATION, 2010

BIOLOGY – HIGHER LEVEL

TIME : 3 HOURS

Section A Answer any five questions from this section. Each question carries 20 marks. Write your answers in the spaces provided on this examination paper. Section B Answer any two questions from this section. Each question carries 30 marks. Write your answers in the spaces provided on this examination paper. Section C Answer any four questions from this section. Each question carries 60 marks. Write your answers in the answer book. It is recommended that you spend not more than 30 minutes on Section A and 30 minutes on Section B, leaving 120 minutes for Section C. You must return this examination paper with your answer book at the end of the examination.

For Examiner’s use only

Sect. Q. Mark

Sect. A Sect. B

Sect. C

TOTAL

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Section A Answer any five questions.

Write your answers in the spaces provided. 1. Answer five of the following:

(a) Name the basic unit of a fat. ________________________________________________________

(b) What is a phospholipid? ___________________________________________________________

(c) Into which two groups are vitamins normally divided?

1. _____________________________________________________________________________

2. _____________________________________________________________________________

(d) Name two trace elements present in food.

1. _____________________________________________________________________________

2. _____________________________________________________________________________

(e) Name a protein biomolecule found in human skin. ______________________________________

(f) List two elements present in food as dissolved salts.

1. _____________________________________________________________________________

2. _____________________________________________________________________________

2. (a) What is a theory?

_______________________________________________________________________________

(b) List two steps involved in following the scientific method which can lead to the development of a

theory.

1. _____________________________________________________________________________

2. _____________________________________________________________________________

(c) Give two limitations of the scientific method.

1. _____________________________________________________________________________

2. _____________________________________________________________________________

(d) Explain what is meant by double-blind in relation to the testing of a drug on a group of patients.

_______________________________________________________________________________

(e) What term is used to distinguish right from wrong (immoral) conduct in relation to the scientific

method?

_______________________________________________________________________________

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3. The diagram shows the relationship between parts of

two nerve cells (neurons).

(a) Name the parts X and Y.

X. ____________________________________

Y. ____________________________________

(b) Describe how a nerve impulse passes from

cell A to cell B.

_______________________________________________________________________________

_______________________________________________________________________________

_______________________________________________________________________________

(c) Explain the importance of the myelin sheath in the transmission of a nerve impulse.

_______________________________________________________________________________

(d) The spinal cord contains white matter and grey matter.

Distinguish between white and grey matter by stating what each contains.

White matter contains _____________________________________________________________

Grey matter contains ______________________________________________________________

4. (a) When light is absorbed by the pigment molecules of a chloroplast, to which specific type of

chlorophyll molecule is it passed?

_______________________________________________________________________________

(b) In a chloroplast, where do the following events occur?

(i) Light-dependent reactions ___________________________________________________

(ii) Light-independent reactions __________________________________________________

(c) There are two pathways in the light-dependent reactions. Which feature(s) do pathway I and

pathway II have in common?

_______________________________________________________________________________

(d) Which pathway is responsible for:

1. The elevation of electrons to their highest level?

_______________________________________________________________________________

2. The acceptance of electrons from the lysis (splitting) of water?

_______________________________________________________________________________

(e) What is the role of NADPH in the dark stage?

_______________________________________________________________________________

_______________________________________________________________________________

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5. (a) To which of the five kingdoms do bacteria belong? ______________________________________

(b) Complete and label the outline diagram below to show three features which may be found in

bacteria but not in other groups of micro-organisms.

(c) Based on shape, name the type of bacteria drawn above.

(d) Name one human disease caused by bacteria of this type. _________________________________

(e) On the axes below, draw a typical bacterial growth curve which includes five phases. Correctly

label the five phases.

6. (a) Distinguish between diffusion and osmosis. ____________________________________________

_______________________________________________________________________________

_______________________________________________________________________________

(b) Give an application of osmosis which is used in food preservation. _________________________

_______________________________________________________________________________

(c) Name the gas which diffuses from a leaf as a result of cellular respiration. ____________________

(d) Name the material which you used as a semi-permeable membrane to demonstrate osmosis in the

laboratory.

_______________________________________________________________________________

(e) Give one essential difference between active transport and other forms of transport across

biological membranes. ____________________________________________________________

_______________________________________________________________________________

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Section B Answer any two questions.

Write your answers in the spaces provided. Part (a) carries 6 marks and part (b) carries 24 marks in each question in this section.

7. (a) State two uses of plant growth regulators.

1. _____________________________________________________________________________

2. _____________________________________________________________________________

(b) Answer the following questions in relation to your investigation on the effect of growth regulators

on plant growth.

(i) In this investigation you made a serial dilution of a stock solution. Explain one of the underlined terms.

_________________________________________________________________________

_________________________________________________________________________

(ii) Name the plant you used in your investigation. ___________________________________

(iii) How did you ensure that the plant was in constant contact with the solution?

_________________________________________________________________________

_________________________________________________________________________

(iv) Why was it necessary to use distilled water?

_________________________________________________________________________

_________________________________________________________________________

_________________________________________________________________________

(v) How did you replicate your experiment?

_________________________________________________________________________

_________________________________________________________________________

(vi) What control did you use?

_________________________________________________________________________

_________________________________________________________________________

(vii) Describe the results you obtained.

_________________________________________________________________________

_________________________________________________________________________

_________________________________________________________________________

(viii) Which plant tissue is used to distribute growth regulators?

_________________________________________________________________________

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8. (a) (i) To which kingdom do yeasts belong? ___________________________________________

(ii) Name one other organism in this kingdom. ______________________________________

(b) Answer the following questions in relation to an experiment that you carried out to investigate the

growth of leaf yeast.

(i) From which plant did you collect the leaf sample?

_________________________________________________________________________

(ii) How did you prepare the leaves when you returned to the laboratory?

_________________________________________________________________________

_________________________________________________________________________

_________________________________________________________________________

_________________________________________________________________________

(iii) Name the nutrient medium that you used.

_________________________________________________________________________

(iv) Describe, in words and/or a labelled diagram, how you conducted the investigation.

_________________________________________________________________________

_________________________________________________________________________

_________________________________________________________________________

_________________________________________________________________________

_________________________________________________________________________

_________________________________________________________________________

_________________________________________________________________________

_________________________________________________________________________

_________________________________________________________________________

_________________________________________________________________________

_________________________________________________________________________

_________________________________________________________________________

_________________________________________________________________________

_________________________________________________________________________

(v) What was the result of your investigation?

_________________________________________________________________________

_________________________________________________________________________

_________________________________________________________________________

_________________________________________________________________________

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9. (a) (i) Name the large biomolecule from which all enzymes are made. ______________________

(ii) What general name is used for the substance upon which an enzyme acts?

_________________________________________________________________________

(b) In your practical work you investigated the effect of temperature on the rate of enzyme action. The

table below shows the results from the investigation.

(i) Name the enzyme you used. __________________________________________________

(ii) Draw a labelled diagram of the apparatus you used.

(iii) Plot a graph to show the results.

Temperature (ºC)

Rate of enzyme action (/min)

5 30

25 180

35 210

45 200

65 40

(iv) What does the graph tell you about the effect of temperature on enzyme action?

_________________________________________________________________________

_________________________________________________________________________

(v) From the graph, what is the rate of enzyme action per minute at 15ºC? ________________

(vi) What happens to the enzyme when the temperature is above 60ºC?

_________________________________________________________________________

(vii) Name one environmental factor which you kept constant in your investigation on the effect of changing temperature on enzyme activity.

_________________________________________________________________________

(viii) What were the products of the reaction in your investigation?

_________________________________________________________________________

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Section C Answer four questions.

Write your answers in the answer book. 10. (a) (i) Define the following terms used in the study of genetics: heterozygous and linkage. (ii) State Mendel’s Law of Independent Assortment. (9) (b) (i) Two gene loci in an organism have the following alleles. Gene locus one : T and t Gene locus two : P and p An organism showing both dominant traits, but with unknown genotype, is represented by

T– p–. Suggest an appropriate cross to establish the genotype of such an organism. Show the possible outcomes (i.e. genotypes of the offspring) of such a cross if the above organism is (a) homozygous for both traits and (b) heterozygous for both traits and there is no linkage.

(ii) Give two instances where Mendel’s Law of Independent Assortment does not apply.

(iii) Name two cell organelles other than the nucleus which contain some DNA. (27) (c) The diagram on the right outlines the production of protein in a cell when DNA is activated.

(i) Step E is a process which involves enzymes. Explain what is happening during Step E.

(ii) Step F leads to the formation of Product G. Name and explain Step F and name Product G.

(iii) Product G moves into the cytoplasm and Structure K attaches to it. What is Structure K?

(iv) What is the structure in the diagram labelled H and what is the significance of the three-letter code?

(v) The start codon on Product G is AUG. What do the letters A, U and G stand for and what would the corresponding code have been on the DNA molecule in the nucleus?

(24) 11. (a) (i) What is meant by the Central Nervous System (CNS) in humans? (ii) Give two tissues which protect this system. (9) (b) (i) Name the functional unit of the kidney. (ii) Draw a diagram of a single kidney unit and its associated blood supply. (iii) Briefly describe how urine is formed by the kidney unit. (27) (c) (i) Name the hormone which controls urine volume. From which endocrine gland

is it secreted?

(ii) Which area of the kidney does this hormone target? (iii) Outline what would happen at the target area when water content in the blood is low. (iv) The kidneys are the main excretory organs in the human body. Name two other organs of

excretion and a waste product other than water which each produces. (24)

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12. (a) (i) Define the terms parasitism and symbiosis. (ii) Distinguish between an ectoparasite and an endoparasite. (9) (b) In a survey of a grasshopper population in a field, 30 grasshoppers were captured and marked with a

small dot of paint before they were released. The next day, 24 grasshoppers were captured using the same technique and of these, 6 were found to be marked with the paint dot.

(i) Suggest a suitable technique for capturing a small animal like a grasshopper.

(ii) Estimate the size of the grasshopper population in the field and show your workings.

(iii) Name this method of estimating population size.

(iv) Distinguish between qualitative and quantitative surveys.

(v) The relationship between two species of insects was investigated. The graph shows the number of both species over a period of time. Identify and explain two reasons why Species A was most likely to have been the prey and Species B the predator.

(vi) Name one abiotic factor which may have influenced the results of this investigation. (27)

(c) In an ecological study, the following numbers of organisms were obtained at each trophic level.

(i) Draw and label a pyramid of numbers to represent this food chain.

(ii) From a named habitat you have investigated, give one organism which could be found at each level in your pyramid.

(iii) Suggest two reasons why there is such a large difference in the numbers of primary and secondary consumers.

(iv) Why do ecologists use ecological pyramids? Give one limitation of their use. (24)

Trophic level

Number of organisms

Producer 1 Primary consumer 300 Secondary consumer 25 Tertiary consumer 5

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13. (a) (i) Distinguish between sexual and asexual reproduction. (ii) Define the term gamete. (9) (b) (i) A flower has four main parts: sepals, petals, stamens and carpels (pistils).

State one function of each of these four parts. (ii) In which of the four named parts does meiosis occur? (iii) Explain the term double fertilisation. (iv) Outline the development of the embryo sac from megaspore mother cell to formation

of the egg cell. (27) (c) Seeds and fruits form after fertilisation and may remain dormant for a long time before germination. (i) Explain the underlined terms and give two advantages of dormancy. (ii) What triggers fruit formation and which part of the carpel usually becomes the fruit? (iii) A seed only germinates in suitable environmental conditions. List two main

environmental conditions needed before a seed can germinate. (iv) Describe the role of digestion and respiration in early seedling growth. (24)

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14. Answer any two of (a), (b) and (c). (30, 30) (a) (i) Distinguish between a prokaryotic and a eukaryotic cell and give one example of each type.

(ii) The diagram above shows a cross-section of a plasma (cell) membrane. Give the main function of a plasma membrane in a cell.

(iii) Give the chemical composition of structures A and B in the diagram. (iv) Cells may be grown using tissue culture. Explain what tissue culture is and give two

conditions necessary for successful tissue culture. (v) Name two applications of tissue culture.

(b) (i) The diagram below shows a stage of mitosis in an animal cell. Name this stage of mitosis.

(ii) Describe what is happening during this stage and state how many chromosomes will be in the nucleus of each new cell.

(iii) Why is DNA replication important before a cell divides by mitosis? Describe, briefly, the process of DNA replication.

(iv) During which phase of the cell cycle does DNA replication occur? (v) Give a function of mitosis in single-celled organisms and a function of mitosis in

multicellular organisms. (c) (i) ATP, NAD and NADP+ are carrier molecules. What do these three abbreviations stand for? (ii) Give the word structure of ATP and draw a simple diagram to indicate where the available

energy is located. (iii) When ATP releases its energy, what is the molecule converted into? (iv) The table below contains some statements relating to biochemical processes in a plant cell.

Copy the table into your answer book and complete the table with a tick () if the statement is true or a cross (×) if the statement is not true for each biochemical process.

Statement Glycolysis Krebs cycle Light-dependent

reactions of photosynthesis

NAD is used NADP is used ATP is produced ATP is required

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15. Answer any two of (a), (b) and (c). (30, 30) (a) The diagrams below show sections of the human male and female reproductive organs.

(i) Name the parts labelled A, B, C, D, E and F. (ii) State the letters that indicate where the following events occur: (1) Fertilisation. (2) Production of testosterone. (3) Development of the foetus. (iii) Define the term secondary sexual characteristics and using either a male or female example

give two secondary sexual characteristics and name the hormone that causes them to develop. (iv) As a human embryo develops it is first organised into three primary germ layers. Name these

three germ layers and list one organ system which arises from each layer. (b) (i) White blood cells can be classified as lymphocytes or monocytes. Distinguish between these

two cell types. (ii) Lymphocytes may also be classified as T-cells or B-cells. Distinguish between these two cell

types. (iii) Name the three main types of blood vessels in the human circulatory system and name the

type of tissue which lines these vessels. (iv) The heart is a major organ in the circulatory system.

Name: 1. The blood vessel which supplies blood to the heart muscle.

2. The blood vessel which drains blood from the heart muscle.

3. The stage of the heartbeat when the heart chambers contract.

4. The stage of the heartbeat when the heart chambers relax. (v) Heartbeat is controlled by specialised nodes in the heart muscle tissue.

Name two of these nodes. (c) (i) Transport tissues in plants include xylem and phloem. Name one substance,

apart from water, transported by each of these tissues. (ii) Name the transport model which explains how water is transported to great heights in tall

trees. Outline how water moves upward in plants as suggested by this model. (iii) Draw a labelled diagram of one of the transport tissues you named above and name the

tissue.

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