2009 biology examination paper

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External Examination 2009

2009 BIOLOGY

Monday 9 November: 9 a.m.

Time: 3 hours

Section A and Part 1 of Section B

Examination material: Question Booklet 1 (21 pages)Question Booklet 2 (12 pages)Question Booklet 3 (8 pages)one multiple-choice answer sheetone SACE registration number label

Approved dictionaries and calculators may be used.

Instructions to Students

1. You will have 10 minutes to read the paper. You must not write in your question booklets, or on your multiple-

choice answer sheet, or use a calculator during this reading time but you may make notes on the scribbling paper provided.

2. This paper is in three sections: Section A and Part 1 of Section B are in Question Booklet 1; Part 2 of Section Bis in Question Booklet 2; and Section C is in Question Booklet 3.

Section A: Multiple-choice Questions (Questions 1 to 25)Answer Section A on the separate multiple-choice answer sheet, using black or blue pen.

Answer all questions in Section A.

Section B: Short-answer Questions (Questions 26 to 34)Answer Part 1 of Section B (Questions 26 to 28) in the spaces provided in Question Booklet 1.Write on page 21 of Question Booklet 1 if you need more space.

Answer Part 2 of Section B (Questions 29 to 34) in the spaces provided in Question Booklet 2.

Write on page 12 of Question Booklet 2 if you need more space.Section C: Extended-response Questions (Questions 35 and 36)Answer both questions in Section C in Question Booklet 3.Write on page 8 of Question Booklet 3 if you need more space.

3. In Section B there is no need to ll all the space provided; clear, well-expressed answers are required. If youdelete part or all of an answer you should clearly indicate your nal answer and label it with the appropriatequestion number.

4. The allocation of marks and suggested allotment of time are as follows:

Section A 50 marks 40 minutesSection B 120 marks 110 minutesSection C 30 marks 30 minutesTotal 200 marks 180 minutes

5. Attach your SACE registration number label to the box at the top of this page. Copy the information fromyour SACE registration number label into the boxes on your multiple-choice answer sheet and on the frontcovers of Question Booklets 2 and 3.

6. At the end of the examination, place Question Booklets 2 and 3, and your multiple-choice answer sheet, insidethe back cover of Question Booklet 1.

ATTACH SACE REGISTRATION NUMBER LABEL

TO THIS BOX

FOR OFFICE

USE ONLY

SUPERVISOR

CHECK

RE-MARKED

QUESTION

BOOKLET

121 pages, 28 questions



2

STUDENT’S DECLARATION ON THE USE OF

CALCULATORS

By signing the examination attendance roll I declare that:

my calculators have been cleared of all memory;•

no external storage media are in use on these calculators.•

I understand that if I do not comply with the above conditions

for the use of calculators I will:

be in breach of the rules;•

have my marks for the examination cancelled or amended;•

be liable to such further penalty, whether by exclusion from•

future examinations or otherwise, as the SACE Board of

South Australia determines.



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SECTION A: MULTIPLE-CHOICE QUESTIONS (Questions 1 to 25)

(50 marks)

Answer all questions in this section.

Each of the twenty- ve multiple-choice questions in Section A involves choosing from four

alternative answers. Read each question carefully. Then indicate the one alternative that you

consider best answers the question by shading the bubble by the appropriate letter alongside

the question number on the multiple-choice answer sheet. Use black or blue pen. It is in your

interest to give an answer to every question in this section of the paper, as no marks are deducted

for incorrect answers. Each question is worth 2 marks. You should spend about 40 minutes on

this section.

1. Which one of the following macromolecules is not used as an energy reserve in a cell?

J. Chitin.

K. Lipid.

L. Glycogen.

M. Starch.

2. Which one of the following substances is present in an onion root cell, but not in a human muscle

cell?

J. DNA.

K. Cellulose.

L. Lipid.

M. Glycogen.

3. The shape of the active site of an enzyme molecule can be altered by

J. lowering the activation energy.

K. the presence of molecules with a shape similar to that of the active site.

L. the presence of molecules with a shape complementary to that of its substrate.

M. increasing the temperature.



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4. A retrovirus contains genetic material in the form of RNA. When a retrovirus infects a host cell,

its RNA is used as a template to make DNA, in a process called ‘reverse transcription’.

Which one of the following alternatives shows the DNA segment that would be made using the

RNA segment template shown below?

RNA segment template: G C C U A G G

J. C G G A U C C

K. G C C T A G G

C G G A T C C

L. C G G A T C C

M. C G G A U C C

G C C U A G G

5. Refer to the following diagram, which shows process A , compound B , and structures 1 and 2 in a

cell:

process A

compound B

compound B

structure 1

structure 2aa

aa

aa

aa

aa

aa

DNA

[This diagram is not drawn to scale.]

Which one of the following combinations identies process A, compound B, and structures 1

and 2?

Process A Compound B Structure 1 Structure 2

J. transcription mRNA ribosome tRNA

K. transcription mRNA amino acid anticodon

L. DNA replication DNA ribosome anticodon

M. DNA replication DNA amino acid tRNA



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6. Refer to the following table, which shows the amino acid sequence for the same part of a

beta-haemoglobin polypeptide in ve species. Each letter represents one amino acid.

Species Amino acid sequence

ghost bat V K A H G K K V L N S

rose-ringed

parakeetV R A H G K K V L T S

hamster V K A H G K K V I H S

platypus V K A H G A K V L T S

black-headed

gullV R A H G K K V L T S

It is reasonable to conclude from the information in the table above that the

J. ghost bat is descended from the hamster.

K. platypus is more closely related to the ghost bat than to the hamster.

L. rose-ringed parakeet and the black-headed gull have the same DNA sequence.

M. hamster is more closely related to the platypus than to the black-headed gull.

7. Refer to the following diagram, which shows a process involving part of the cell membrane and a

vesicle inside a cell:

cell membrane

vesicleinside cell

outside cell

Which one of the following statements identies and describes the process illustrated?

J. Exocytosis, which is a passive process.

K. Endocytosis, which is a passive process.

L. Exocytosis, which is an active process.

M. Endocytosis, which is an active process.



6

8. The following table shows four sets of conditions in which the same number of identical human

skin cells were cultured. All other factors were kept constant.

Which one of the sets of conditions, J, K, L, or M, would result in the highest rate of cell division?

Conditions

Temperature Light Carbon dioxide Oxygen

J. 25°C not present present present

K. 35°C present not present not present

L. 25°C present not present not present

M. 35°C not present present present

9. The movement of chloroplasts within the cytoplasm of some green plant cells maximises theexposure of the chloroplasts to sunlight.

Which one of the following cell structures enables this movement of chloroplasts to occur?

J. Endoplasmic reticulum.

K. Cytoskeleton.

L. Golgi body.

M. Cell membrane.

10. Refer to the following diagram, which shows an organelle found in a eukaryotic cell:

membrane A

membrane B

Source: Adapted from B. LeCornu & T. Diercks, Biology: Levels of Life,

2nd edn (rev.), Briton Books, Adelaide, 2005, page 48

The organelle shown above is thought to have evolved by endosymbiotic events approximately

1.5 billion years ago.

Which one of the following combinations identies the organelle, the origin of membrane A, and

the origin of membrane B?

Organelle Origin of membrane A Origin of membrane B

J. mitochondrion heterotrophic prokaryote host cell membrane

K. chloroplast host cell membrane autotrophic prokaryote

L. chloroplast autotrophic prokaryote host cell membrane

M. mitochondrion host cell membrane heterotrophic prokaryote



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11. Two types of gene are involved in regulating the cell cycle. Proto-oncogenes control the start of

cell division, and tumour-suppressor genes stop cell division. A mutated proto-oncogene can result

in cancer. Both proto-oncogenes and tumour-suppressor genes are susceptible to carcinogens.

Which one of the following combinations of type of gene, presence or absence of carcinogen, and

effect on the cell cycle is consistent with the information above?

Type of gene Carcinogen Effect on the cell cycle

J. proto-oncogene present uncontrolled cell division

K. tumour suppressor present cell division is stopped

L. proto-oncogene not present cell division is stopped

M. tumour suppressor not present uncontrolled cell division

12. Refer to the following diagram, which shows two compartments, A and B , separated by asemi-permeable membrane. The initial volume of solution in each compartment is 5 mL. The

initial concentrations of substances in each compartment are shown in parts per million (ppm).

potassium ions (K +)

sodium ions (Na+)

sucrose

potassium ions (K +)

sodium ions (Na+)

sucrose

5 ppm

20 ppm

25 ppm

25 ppm

30 ppm

35 ppm

semi-permeable membrane(permeable to K +, Na+, and water, but not to sucrose)

Compartment A Compartment B

According to the information in the diagram above, there would be an overall movement of

J. potassium ions from compartment A to compartment B.

K. water from compartment A to compartment B.

L. sodium ions from compartment A to compartment B.

M. sucrose from compartment B to compartment A.

13. A human heart is a major organ composed of

J. one type of cell.

K. cells that contain different genes.

L. tissues that contain different genes.

M. genetically identical cells.



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14. Genetic variation does not arise during

J. the cell cycle, when mistakes in copying the DNA base sequence occur.

K. the rst division of meiosis, when genes are exchanged between the members of a pair of

homologous chromosomes.

L. the second division of meiosis, when pairs of homologous chromosomes align themselvesindependently of each other.

M. fertilisation, when a random combination of gametes forms a zygote.

15. If the body temperature of a healthy person falls below the normal setting of 37°C

J. an increased amount of the hormone thyroxine is released, resulting in a decrease in heat

loss.

K. a decreased amount of sweating occurs, resulting in an increase in heat production.

L. vasodilation occurs, resulting in an increase in heat production.

M. vasoconstriction occurs, resulting in a decrease in heat loss.

16. Bacillus thuringiensis (Bt) is a bacterium that synthesises crystal-like proteins (Cry proteins).

Cry proteins bind to specic receptors on the intestinal lining of specic groups of insects,

rupturing the cells and killing the insects within a few days.

Cotton plants do not naturally synthesise Cry proteins. Biotechnology is used to produce cotton

plants that do synthesise Cry proteins.

Which one of the following processes could be used to produce a cotton plant with the potential tosynthesise Cry proteins in all its cells?

J. Using a bacterial vector to transfer Cry proteins into the cells of a cotton plant.

K. Transferring the genes for Cry proteins into the cells of a cotton plant.

L. Using microinjection to transfer Cry proteins into the fertilised egg cell of a cotton plant.

M. Transferring the genes for Cry proteins into the fertilised egg cell of a cotton plant.

17. In the process of

J. aerobic respiration, autotrophs and heterotrophs convert chemical energy into heat energy.

K. aerobic respiration, autotrophs convert light energy into chemical energy.

L. photosynthesis, heterotrophs convert light energy into chemical energy.

M. photosynthesis, autotrophs and heterotrophs convert chemical energy into heat energy.



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18. Refer to the following diagram, which shows the respiratory system of an insect:

spiracle tracheole trachea

There are many openings called ‘spiracles’ on the surface of an insect’s body. Each spiracle

connects to an air tube (trachea) that branches throughout the insect’s body. Air is moved in and

out of the air tubes by contractions of the insect’s body.

The many tiny branches (tracheoles) of the air tubes deliver air direct to the body cells of the

insect. There is moisture at the end of each tiny branch. Gas exchange between the tiny branches

and the body cells occurs by diffusion.

Which one of the following descriptions does not apply to both an insect and a human being?

J. There is a large surface area for gas exchange because of the presence of many tiny

structures.

K. Air is delivered direct from tiny branches to body cells for gas exchange.

L. The mechanism of gas exchange is diffusion.

M. Water is lost by evaporation during gas exchange.



10

19. Refer to the following diagram, which shows a dividing cell from a diploid organism:

This cell

J. is undergoing mitosis.

K. has a haploid number of 6.

L. is undergoing the rst division of meiosis.

M. will produce genetically variable daughter cells.

20. Various types of organism, including native bushes, insects, small birds, and lizards, live in the

shrubbery in a suburban backyard.

These organisms together make up

J. a community.

K. an ecosystem.

L. a population.

M. a habitat.

21. Which one of the following statements describes an example of a mechanism that would help to

maintain reproductive isolation?

J. The production of similar mating calls by two species of frog.

K. The production of gametes during the same season by two species of pine tree.

L. The mating and production of infertile offspring by two individuals.M. The separation of two populations of the same species by a geographical barrier.



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22. Refer to the following graph, which shows the level of productivity of six types of ecosystem:

10000

8000

6000

4000

2000

0temperate

forestsavannah woodland lakes and

streamsagricultural

land estuaries

p r o d u c t i v i t y ( a r b

i t r a r y u n i t s )

type of ecosystem

Which one of the following statements is most consistent with the data in the graph above?

J. There is more water available in savannah than in agricultural land.K. There are more sunlight hours in woodland than in savannah.

L. The concentration of nutrients available for plant growth is higher in estuaries than in

temperate forest.

M. The productivity of estuaries is four times higher than that of lakes and streams.

23. The wounds of patients who have undergone surgery are susceptible to bacterial infections.

Enterococcus faecium and methicillin-resistant Staphylococcus aureus (MRSA) are species of

bacterium associated with these infections. Methicillin and other antibiotics are often used to treat

infections of surgical wounds, but do not always cure them.

Which one of the following statements about the development of resistance to antibiotics in

bacteria such as Enterococcus faecium and MRSA is correct?

J. Individual bacteria that are not affected by antibiotics evolve resistance.

K. Bacteria that are exposed to methicillin will become resistant to all antibiotics to which

they are exposed.

L. A number of individuals in a population of bacteria may be resistant to methicillin.

M. A person who is resistant to methicillin will pass on the methicillin-resistant gene to the

bacteria.



12

24. Refer to the following diagram of a food web:

dingo

desert hopping mousekoala

gum tree

brown snake

frill-necked lizard

native insect

native grass

Which one of the following statements is incorrect?

J. Frill-necked lizards and dingoes belong to different trophic levels.

K. Gum trees and native grasses are both in the rst trophic level.

L. Koalas and desert hopping mice belong to the same trophic level.

M. Brown snakes belong to both the third and the fourth trophic levels.



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25. Two students investigated anaerobic respiration by taking measurements of the volume of carbon

dioxide (CO2) produced by yeast during bread-making.

Both students used the same experimental conditions when collecting the data recorded in the

table below:

Sample number Volume of CO2 produced (arbitrary units)Student A Student B

1 1.02 1.01

2 1.10 1.02

3 1.15 1.02

4 0.99 1.03

5 1.09 1.02

Average 1.07 1.02

If the true value for this experiment was 1.05 (arbitrary units), the data in the table indicate that

the set of data collected by student A

J. has the same random errors as the set of data collected by student B.

K. has random errors but the set of data collected by student B does not.

L. is more accurate than the set of data collected by student B.

M. is more reliable than the set of data collected by student B.



14

SECTION B: SHORT-ANSWER QUESTIONS (Questions 26 to 34)

(120 marks)

You should spend about 110 minutes on this section. Answers may be in note form. The allocation of

marks is shown in brackets at the end of each part of each question. Answer all questions in the spaces

provided.

Part 1 (Questions 26 to 28)

(60 marks)

26. Silk, which is produced by spiders when building webs, is one of the strongest substances known.

It is ve times stronger than steel in a weight-to-weight comparison, more elastic than nylon, and

lighter and stronger than Kevlar ®. Its many potential uses include body armour in the military,

articial tendons, medical sutures, and biodegradable shing lines.

Spider silk is made of a protein. Scientists have located and isolated the gene for the spider silk

protein from orb-weaving spiders that produce the strongest silk.

(a) Describe the features of a probe that would be used to locate the gene for the spider silk

protein in the spider DNA.

_______________________________________________________________________________________________________

_______________________________________________________________________________________________________

_______________________________________________________________________________________________________

_______________________________________________________________________________________________________

____________________________________________________________________________________________ (4 marks)

(b) Scientists hope to use genetic engineering techniques to create synthetic spider silk that

can be used commercially. Their rst attempts have involved genetically modifying

bacterial cells to produce the spider silk protein.

Describe the process that the scientists would use to insert the isolated gene for the spider silk

protein into the plasmid of a bacterial cell.

_______________________________________________________________________________________________________

_______________________________________________________________________________________________________

_______________________________________________________________________________________________________

_______________________________________________________________________________________________________

____________________________________________________________________________________________ (4 marks)



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(c) Two amino acids, glycine and alanine, make up 70% of spider silk protein. Bacterial

cells that were genetically modied to produce spider silk protein died as a result of the

depletion of these two amino acids.

Explain why the bacterial cells died as a result of the depletion of these two amino acids.

_______________________________________________________________________________________________________

_______________________________________________________________________________________________________

_______________________________________________________________________________________________________

_______________________________________________________________________________________________________

____________________________________________________________________________________________ (4 marks)

(d) Scientists have recently inserted the gene for the spider silk protein into goats in such a

way that it is present in all the goats’ cells, but is expressed only in their milk-producingcells. These ‘spider-goats’ produce between 1 and 2 grams of spider silk in every litre of

milk.

Explain one argument that may be used against the genetic modication of goats to produce

silk.

_______________________________________________________________________________________________________

_______________________________________________________________________________________________________

_______________________________________________________________________________________________________

_______________________________________________________________________________________________________

____________________________________________________________________________________________ (4 marks)



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27. Refer to the following diagram, which shows the movement of acetylcholine, a chemical that

moves across the synapse (the gap between two nerve cells):

acetylcholine

nerve cell 1

vesicle

synapse

nerve cell 2

[This diagram is not drawn to scale.]

(a) Describe the process by which nerve cell 1 releases acetylcholine into the synapse, as

shown in the diagram above.

_______________________________________________________________________________________________________

_______________________________________________________________________________________________________

_______________________________________________________________________________________________________

_______________________________________________________________________________________________________

____________________________________________________________________________________________ (4 marks)

(b) Name the organelle that forms the vesicles containing acetylcholine.

____________________________________________________________________________________________ (2 marks)

(c) After acetylcholine has been released into the synapse, it binds to specic membrane

receptors on nerve cell 2 and triggers a nerve impulse.

Explain why acetylcholine will bind only to acetylcholine membrane receptors and not to

membrane receptors for any other chemical.

_______________________________________________________________________________________________________

_______________________________________________________________________________________________________

_______________________________________________________________________________________________________

_______________________________________________________________________________________________________

____________________________________________________________________________________________ (4 marks)



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(d) Acetylcholine must be broken down very quickly after it has triggered a nerve impulse,

in order to ‘reset’ the synapse in preparation for the next nerve impulse. The enzyme

acetylcholinesterase (AChE) breaks acetylcholine down into choline and acetate at the rate

of 5000 molecules per second per molecule of enzyme. The breakdown of acetylcholine

is represented by the following word equation:

acetylcholine choline + acetateAChE

Explain how AChE lowers the activation energy needed for this reaction.

_______________________________________________________________________________________________________

_______________________________________________________________________________________________________

_______________________________________________________________________________________________________

_______________________________________________________________________________________________________

____________________________________________________________________________________________ (4 marks)

(e) Diisopropyl uorophosphate (DIFP) is a nerve toxin that inhibits AChE. The subsequent

accumulation of acetylcholine in the synapse results in paralysis of muscles, including the

respiratory muscles, followed by death.

Explain how the presence of DIFP results in an accumulation of acetylcholine in the synapse.

_______________________________________________________________________________________________________

_______________________________________________________________________________________________________

_______________________________________________________________________________________________________

_______________________________________________________________________________________________________

____________________________________________________________________________________________ (4 marks)



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28. Refer to the following diagram, which shows a pair of guard cells. Guard cells are specialised

photosynthetic cells found on the leaf surfaces of many green plants.

guard cell

vacuole

chloroplast

epidermal cell

guard cell

The volume of a guard cell varies with different environmental conditions.

Refer to the following table, which shows the results of an experiment to determine the change in

volume of one guard cell over a 24-hour period, beginning at midnight:

time (h) 0(midnight)

4 8 12(noon)

16 20 24(midnight)

volume of guard cell

(m3)3000 4000 4750 5000 4750 4000 3000

(a) On the grid below, graph the data in the table above to show the change in volume of

the guard cell over the 24-hour period.

(4 marks)



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(b) Describe the change in volume of the guard cell over the 24-hour period.

_______________________________________________________________________________________________________

____________________________________________________________________________________________ (2 marks)

(c) Using only the information provided, state one factor in the design of this experiment

that would affect the reliability of the results.

_______________________________________________________________________________________________________

____________________________________________________________________________________________ (2 marks)

(d) State the dependent variable in this experiment.

____________________________________________________________________________________________ (2 marks)

(e) It was later found that a systematic error had affected the results of the experiment.

Explain how this systematic error would have been identied.

_______________________________________________________________________________________________________

_______________________________________________________________________________________________________

_______________________________________________________________________________________________________

_______________________________________________________________________________________________________

____________________________________________________________________________________________ (4 marks)

(f) Explain how an increase in its volume may affect a guard cell’s ability to obtain the

materials it needs from its environment.

_______________________________________________________________________________________________________

_______________________________________________________________________________________________________

_______________________________________________________________________________________________________

_______________________________________________________________________________________________________

____________________________________________________________________________________________ (4 marks)



20

(g) Potassium ions (K +) can move against a concentration gradient through the cell membrane

and into the guard cells.

The diagram below shows a cross section of the cell membrane from a guard cell:

X

X

ATP

ADP

potassium ions

outside

guard cell

insideguard cell

(i) Name the cellular process by which potassium ions move into the guard cell against

a concentration gradient.

_______________________________________________________________________________________ (2 marks)

(ii) Name membrane component X.

_______________________________________________________________________________________ (2 marks)

(iii) Explain how the process of aerobic respiration enables ATP to be formed from ADP.

__________________________________________________________________________________________________

__________________________________________________________________________________________________

__________________________________________________________________________________________________

__________________________________________________________________________________________________

_______________________________________________________________________________________ (4 marks)



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© SACE Board of South Australia 2009

You may write on this page if you need more space to nish your answers to any questions in

Part 1 of Section B. Make sure to label each answer carefully (e.g. 27(a) continued).

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FOR OFFICE

USE ONLY

SUPERVISOR

CHECK

RE-MARKED

SACE REGISTRATION NUMBER

FIGURES

BIOLOGY

CHECK

LETTER

SEQ BIN


2009 BIOLOGY


Part 2 of Section B

Write your answers to Part 2 of Section B in this question booklet.

QUESTION

BOOKLET




2



3 PLEASE TURN OVER

SECTION B: SHORT-ANSWER QUESTIONS

Part 2 (Questions 29 to 34)

(60 marks)

Answer all questions in the spaces provided.

29. Very small amounts of DNA can be collected from a crime scene.

(a) State how the polymerase chain reaction (PCR) enables very small amounts of DNA from

a crime scene to be used as evidence.

_______________________________________________________________________________________________________

____________________________________________________________________________________________ (2 marks)

(b) Refer to the following diagram, which shows three DNA ngerprints: a mixed sample of

DNA from a crime scene, the DNA of the victim, and the DNA of one suspect:

DNA of

victim

DNA of one

suspect

Mixed sample

of DNA from

crime scene

DNA

fragment

A

B

C

D

E

F

With reference to the information in the diagram above, explain how the DNA evidence could

be used to support the suspect’s innocence.

_______________________________________________________________________________________________________

_______________________________________________________________________________________________________

_______________________________________________________________________________________________________

_______________________________________________________________________________________________________

____________________________________________________________________________________________ (4 marks)



4

30. The human eye is a sensory organ. Refer to the following diagram, which shows the location of

the iris, cornea, retina, and optic nerve in the human eye:

optic nerve

retinairis

cornea

(a) State one important function of sensory receptors.

_______________________________________________________________________________________________________

____________________________________________________________________________________________ (2 marks)

(b) Receptor cells in the retina transmit information, via the optic nerve, to the brain. Cellsin the cornea have receptors for steroid hormones.

Describe two differences between the transmission of information by nerves and the

transmission of information by hormones.

Difference 1: ________________________________________________________________________________________

_______________________________________________________________________________________________________

_______________________________________________________________________________________________________

Difference 2: ________________________________________________________________________________________

_______________________________________________________________________________________________________

____________________________________________________________________________________________ (4 marks)



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(c) Receptor cells in the retina transmit information, via nerves, to the dilator muscle in the

iris. The dilator muscle alters the size of the iris and consequently changes the amount of

light entering the eye. This is a reex response.

(i) Name the effector in the reex response described above.

_______________________________________________________________________________________ (2 marks)

(ii) State why this response is called a reex response.

__________________________________________________________________________________________________

_______________________________________________________________________________________ (2 marks)



6

31. It is necessary for double-stranded DNA to break for the process of crossing over to occur.

In an experiment to investigate the number and position of double-stranded DNA breaks (DSBs),

biologists examined a section of DNA from a species of yeast.

The graph below shows the results of this experiment:

30

25

20

15

10

5

0

n u m b e r o f D S B s

protein coding gene

non-protein coding gene

gene 1 gene 2 gene 3 gene 4 gene 5 gene 6

1 kbp

position along section of DNA molecule

Genes 1, 3, 5, and 6 code for proteins. Genes 2 and 4 produce non-protein coding RNA (ncRNA).

(a) Using the scale in the graph above, estimate the length in kilobase pairs (kbp) of gene 4.

____________________________________________________________________________________________ (2 marks)

(b) With reference to the data in the graph:

(i) state the greatest number of DSBs at any position along this section of DNA.

_______________________________________________________________________________________ (2 marks)

(ii) name the gene in which the greatest number of DSBs occurs.

_______________________________________________________________________________________ (2 marks)

(c) The biologists who obtained the results shown in the graph above were investigating the

connection between sections of DNA that produce ncRNA and the likelihood of DSBsoccurring.

State one conclusion that is consistent with these results.

_______________________________________________________________________________________________________

____________________________________________________________________________________________ (2 marks)



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(d) (i) In Box 1, draw a diagram to show one occurrence of crossing over in one pair of

chromosomes.

Box 1

(2 marks)

(ii) In Box 2, draw a diagram to show the result of the crossing over that you have

drawn in Box 1.

Box 2

(2 marks)

(e) Explain what would be the likely consequence for a cell if DSBs occurred in protein

coding sections of DNA.

_______________________________________________________________________________________________________

_______________________________________________________________________________________________________

_______________________________________________________________________________________________________

_______________________________________________________________________________________________________

____________________________________________________________________________________________ (4 marks)



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32. Smoking increases the risk of developing lung cancer more in some people than in others.

Scientists say that a simple urine test can predict whether or not a smoker is likely to develop lung

cancer.

NNAL is a product of a carcinogen in cigarette smoke. Experimental trials found that the

likelihood of developing lung cancer is 8.5 times greater for smokers with the highest levels of

NNAL in their urine than for those with the lowest levels.

The following diagram shows part of a human nephron:

direction of blood flow

(a) On the diagram above, draw an arrow to show the pathway followed by a molecule, such

as NNAL, as it travels from the blood to the urine.

(2 marks)

(b) Describe one way in which the ndings of the experimental trials involving NNAL and

smokers may benet society.

_______________________________________________________________________________________________________

_______________________________________________________________________________________________________

_______________________________________________________________________________________________________

_______________________________________________________________________________________________________

_______________________________________________________________________________________________________

____________________________________________________________________________________________ (4 marks)



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33. Refer to the following photograph, which shows a young zenkey. A zenkey is the offspring

produced from the mating of a male zebra (with a diploid number of 44) and a female donkey

(with a diploid number of 62).

Source: www.smh.com.au

(a) State the number of chromosomes in a body cell of a zenkey.

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(b) The cells of zenkeys are able to undergo mitotic cell division.

Describe two consecutive steps that involve the movement of chromosomes during mitotic

cell division.

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(c) State one factor that would prevent the cells of a zenkey from completing meiosis.

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10

34. In the wet season on the African plains, animals such as wildebeest migrate to follow the

availability of grasses containing high levels of phosphates and nitrates. The wildebeest eat the

leaves, but not the stems, of the grasses.

Acacia is a plant that threatens the growth of the grasses. Acacia seeds are widely distributed

during the dry season, and germinate in the wet season. As the grasses are eaten by the wildebeest,

the acacias have more resources available to them and grow into large trees. The conditions arethen no longer suitable for the grasses, and the wildebeest move away to nd food elsewhere.

Acacias are a source of food for animals such as the dik-dik, a type of antelope. Dik-diks eat all

the easily accessible leaves of the acacias.

Towards the end of the wet season the acacias are destroyed by elephants, which knock them

down and eat the branches.

(a) The remains of the acacias contain phosphates and nitrates.

Name the type of organism that returns these phosphates and nitrates to the soil.

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(b) Name the process described above that results in a change in the mixture of species.

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(c) With reference to the information above:

(i) state one biotic factor that is important for the survival of the dik-dik.

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(ii) explain how the destruction of the acacias enables the population of grasses to

increase at the beginning of the next wet season.

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11 PLEASE TURN OVER

(d) The African elephant is an endangered species.

Explain why the best way to preserve the African elephant is to preserve the African plains

habitat.

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12

You may write on this page if you need more space to nish your answers to any questions in

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SACE REGISTRATION NUMBER

FIGURES

BIOLOGY

CHECK

LETTER

SEQ BIN


FOR OFFICE

USE ONLY

SUPERVISOR

CHECK

RE-MARKED

2009 BIOLOGY


Section C

Write your answers to Section C in this question booklet.

QUESTION

BOOKLET




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3 PLEASE TURN OVER

SECTION C: EXTENDED-RESPONSE QUESTIONS (Questions 35 and 36)

(30 marks)

Answer both questions in this section.

Write your answers in this question booklet:

Question 35, on pages 4 and 5, is worth 15 marks.•

Question 36, on pages 6 and 7, is worth 15 marks.•

You should spend about 30 minutes on this section, 5 to 10 minutes

planning and 20 to 25 minutes writing.

Credit will be given for clear, well-expressed answers that are well

organised and relevant to the questions.



4

35. The ef cient supply of oxygen and glucose to cells enhances athletic performance. At times the

supply of oxygen to cells is inadequate to meet their energy demand. Some athletes choose to use

performance-enhancing drugs to improve the supply of oxygen and / or glucose to their cells.

Explain how the structure of blood capillaries facilitates the supply of glucose to cells.•

Describe how energy is made available in the cells of athletes under• anaerobic conditions.

Describe how choices about drug use can affect the well-being of an athlete.•

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36. The human population is approaching 7 billion. If growth trends continue, the human population

will reach 9 billion by 2050.

Use the human species as an example to explain the idea that• r and K strategies are

extremes on a continuum.

Explain why the exponential growth of the human population is not sustainable.•

Discuss• one ethical issue associated with the level of human population predicted for 2050.

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8


You may write on this page if you need more space to nish your answers to Questions 35 and 36.

Make sure to label each answer carefully (e.g. 35 continued).

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BIOLOGY 2009

ACKNOWLEDGMENT

The photograph for Question 33 on page 9 is copyright © AFP.

The SACE Board of South Australia has made every effort to trace copyright holders. If however,

any material has been incorrectly acknowledged, we apologise and invite the copyright holder to

contact us.

2009 biology examination paper

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