Name:________________Class:______(__)

S.6 Mock Examination (2021-2022)

BIOLOGY PAPER 1

Time allowed: 2 hours 30 minutes

This paper must be answered in English.
Total marks: 120 marks

GENERAL INSTRUCTIONS

1. There are TWO sections, A and B, in this Paper. You are advised to finish Section A in about 35
minutes.

2. Section A consists of multiple-choice questions in this question paper. Section B contains

conventional questions printed separately in Question-Answer Book B.

3. Answers to Section A should be marked on the Multiple-choice Answer Sheet while answers to
Section B should be written in the spaces provided in Question-Answer Book B. The Answer
Sheet for Section A and the Question-Answer Book B for Section B will be collected
separately at the end of the examination.

INSTRUCTIONS FOR SECTION A (MULTIPLE-CHOICE QUESTIONS)

1. Read carefully the instructions on the Answer Sheet. After the announcement of the start of the
examination, you should fill in the information required in the space provided. No extra time will be
given for filling in the required information after the ‘Time is up’ announcement.

2. When told to open this book, you should check that all the questions are there. Look for the words
‘END OF SECTION A’ after the last question.

3. All questions carry equal marks.

4. ANSWER ALL QUESTIONS. You are advised to use an HB pencil to mark all the answers on the
Answer Sheet, so that wrong marks can be completely erased with a clean rubber. You must mark
the answers clearly; otherwise you will lose marks if the answers cannot be captured.

5. You should mark only ONE answer for each question. If you mark more than one answer, you will
receive NO MARKS for that question.

6. No marks will be deducted for wrong answers.

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 SECTION A (MULTIPLE-CHOICE QUESTIONS)

There are 36 questions in this section.

The diagrams in this section are NOT necessarily drawn to scale.

1. Which of the following reactions takes place in plants but not in animals?

A. glucose → cellulose
B. glucose → glycogen
C. glycogen → glucose
D. starch → glucose

2. The photomicrograph below shows cells at different stages of the cell cycle.

1 2

A chemical can prevent the formation of spindle fibres during mitosis. Which cell
represents the first stage to be affected by the chemical?

A. 1
B. 2
C. 3
D. 4

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 S.6 Biology Mock Examination (2021-2022)

Directions: Questions 3 and 4 refer to the diagram below, which shows a broad bean seed.

P
S
Q

3. Which structure of the seed serves a similar function to amniotic fluid?

A. P
B. Q
C. R
D. S

4. Which of the following graphs correctly shows the changes in the fresh masses of
structures P and Q during germination?

A. B.
Fresh mass (g)

Fresh mass (g)

P P

Q Q

0 10 0 10
Time (day) Time (day)

C. D.

Q
Fresh mass (g)
Fresh mass (g)

Q P

0 10 0 10
Time (day) Time (day)

3 .
Directions: Questions 5 and 6 refer to the diagram below, which shows the longitudinal
section of a tooth and its associated structures.

2
4
3

5. Which of the labelled structures are hard and rigid?

A. 1 and 2 only
B. 2 and 4 only
C. 1, 2 and 4 only
D. 1, 2 and 5 only

6. A deficiency disease is characterized by swelling and breeding of structure 3. Which

food can be used to prevent this disease?

A. orange
B. liver
C. milk
D. egg yolk

7. Which of the following blood vessels has the greatest fluctuation in blood glucose levels
within the day?

A. aorta
B. hepatic vein
C. hepatic artery
D. hepatic portal vein

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 S.6 Biology Mock Examination (2021-2022)

8. The diagram below shows the longitudinal section of a blood vessel.

valve

A B

Which of the following statements is correct?

A. The walls of the blood vessel contract to open the valves.

B. The elastic walls recoil to close the valves.
C. Blood flows from A to B and pushes the valves open.
D. The valves close to prevent the backflow of blood from A to B.

9. The graph below shows the effect of carbon dioxide concentration on the rate of
photosynthesis at low and high light intensities.

Y
high light intensity
Rate of photosynthesis

X
Z
low light intensity

Carbon dioxide concentration

Which of the following combinations correctly identify the limiting factors at points X,
Y and Z?

X Y Z
A. light intensity carbon dioxide light intensity
B. light intensity carbon dioxide carbon dioxide
C. carbon dioxide light intensity light intensity
D. carbon dioxide light intensity carbon dioxide

5 .
10. The set-up below, which is used to investigate respiration in germinating seeds.

delivery tube
thermometer

ruler
germinating seeds

wire gauze
coloured liquid
soda lime

After four hours, the liquid level in the delivery tube will

A. fall because of the carbon dioxide given out by the germinating seeds.
B. rise because of the oxygen taken in by the germinating seeds.
C. rise because of the heat released by the germinating seeds.
D. remain unchanged because the volume of carbon dioxide given out equals the
volume of oxygen taken in.

11. The pie charts below show the change in the proportion of individuals possessing at least
one allele X in a lizard population over 100 generations.

100 generations

Key: proportion of individuals possessing at least one allele X

proportion of individuals possessing alleles other than allele X

Based on the pie charts above, which of the following statements is/are correct?

(1) Allele X must be a dominant allele.

(2) Allele X can cause disease in heterozygous condition.
(3) Individuals possessing two copies of allele X are more likely to survive and
reproduce.

A. (3) only
B. (1) and (2) only
C. (1) and (3) only
D. (2) and (3) only

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 S.6 Biology Mock Examination (2021-2022)

12. Which of the following does not require energy released by respiration?
A. uptake of oxygen from air sacs
B. uptake of glucose from the small intestine
C. release of neurotransmitters into the synaptic cleft
D. release of antibodies by lymphocytes

Directions: Questions 13 and 14 refer to an experiment to investigate changes in pH when

lipase is added to a food sample having a high fat content. The graph below
shows the results.

6
pH
5

0 2 4 6 8 10 12 14
Time (minute)

13. The decrease in pH during the first 10 minutes is due to the formation of

A. fatty acid.
B. lactic acid.
C. amino acid.
D. hydrochloric acid.

14. Which of the following is/are the possible explanation(s) of the results between 10
minutes and 14 minutes?

(1) All the lipase active sites are occupied.

(2) Substrate concentration becomes the limiting factor.
(3) Lipase becomes denatured.

A. (1) only
B. (2) only
C. (1) and (3) only
D. (2) and (3) only

7 .
15. The diagrams below show the appearance of two sections of spring onion that have been
split longitudinally halfway and immersed in two different liquids.

waxy outer
layer
in liquid P in liquid Q

Which of the following statements are correct?

(1) In liquid P, cells in the outer layer of the spring onion expand more than those in the
inner layer.
(2) In liquid Q, cells in the inner layer of the spring onion become plasmolysed.
(3) The water potential of liquid P is higher than that of liquid Q.

A. (1) and (2) only

B. (1) and (3) only
C. (2) and (3) only
D. (1), (2) and (3)

16. Which of the following are genetically identical?

A. buds of the same tuber

B. maize grains on the same cob
C. sperms produced in a human testis
D. the placenta and the uterine wall in a pregnant woman

17. After a woman receives a surgery to tie and cut both of her oviducts, which of the
following may still occur?

(1) ovulation
(2) menstruation
(3) production of female sex hormones

A. (1) and (2) only

B. (1) and (3) only
C. (2) and (3) only
D. (1), (2) and (3)

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 S.6 Biology Mock Examination (2021-2022)

18. In a family, the mother has blood group B and the two children have blood groups A and
O. What is the probability that her next child will be a girl of blood group A?
3
A. /4
1
B. /2
1
C. /4
1
D. /8

19. A fruit fly (Drosophila melanogaster) has four pairs of chromosomes in its body cells.
After meiosis I, how many chromatids are present in each daughter cell?

A. 4
B. 8
C. 16
D. 32

20. The diagram below shows an experiment on auxins.

agar block
coleoptile In darkness
with auxins
top 2
cut 1 2

after
cut 2 decapitated
base 2 days
coleoptile
plain agar
block

agar block In darkness

coleoptile with auxins
base 3
cut 4 4

after
cut 4 decapitated
top 2 days
coleoptile
(shoot inverted)
plain agar
block

Which of the following conclusions can be drawn from the results of the experiment?

A. Auxins are produced at the tip of the coleoptile.

B. Phototropism is due to the uneven distribution of auxins in the shoot.
C. Transport of auxins involves an active process.
D. Transport of auxins is unidirectional.

9 .
Directions: Questions 21 and 22 refer to the diagram below, which shows the human
digestive system.

5 2

4 3

21. Chemical digestion of proteins takes place in

A. structures 2 and 3 only.

B. structures 2 and 4 only.
C. structures 1, 2 and 3 only.
D. structures 1, 2 and 4 only.

22. Structure 5 is regarded as a digestive gland because it

A. converts stored glycogen into glucose.

B. carries out deamination.
C. breaks down red blood cells.
D. produces bile.

23. Which of the following substances is/are not normally found in the blood plasma?

(1) antibodies
(2) haemoglobin
(3) glucagon

A. (1) only
B. (2) only
C. (3) only
D. (2) and (3) only

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 S.6 Biology Mock Examination (2021-2022)

24. The table below shows the number of differences between the amino acid sequence of
cytochrome c (an important protein) of the five species.

Number of amino acid differences

Species P Q R S T

P -

Q 12 -

R 11 1 -

S 10 3 2 -

T 11 6 5 3 -

Which of the following evolutionary trees best illustrates the phylogenetic relationships
of the five mammalian species?

A. B.

Q R S T P T R S P Q

ancestor ancestor

C. D.

T S R Q P T R Q S P

ancestor ancestor

11 .
25. The following diagram shows four types of human cells (not drawn to scale).

cell type P cell type Q cell type R

cell type S

structure X

Structure X of cell type S is found in

A. the dorsal root ganglion of a spinal nerve.

B. the ventral root of a spinal nerve.
C. the grey matter of the spinal cord.
D. the white matter of the cerebrum.

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 S.6 Biology Mock Examination (2021-2022)
26. The graph below shows the changes in the rate of oxygen uptake of a person before,
during and after exercise.

before after
exercise exercise exercise
rate of oxygen uptake
(arbitrary unit)

m n o

p q r

0 5 10 15 20 25 30 35
time (min)

The oxygen debt of the person can be obtained by measuring the area of

A. m.
B. o.
C. n + o.
D. o + r.

27. A scientist extracted some mitochondria from a mouse liver tissue and transferred the
extracted mitochondria to a solution containing ADP and inorganic phosphate (Pi). He
then added two chemicals, succinate and cyanide, one by one into the solution mixture.
The amount of oxygen consumed and the amount of ATP synthesized by the
mitochondria were measured. The graph below shows the results of the experiment.

succinate cyanide
added added
amount of oxygen consumed or
ATP synthesized

synthesis of ATP
oxygen consumption

time

13 .
 Which of the following can be deduced from the results of the experiment?

(1) Succinate is one of the intermediates of glycolysis.

(2) Cyanide inhibits the synthesis of ATP in oxidative phosphorylation.
(3) Oxidative phosphorylation takes place at the inner membrane of mitochondria.

A. (2) only
B. (3) only
C. (1) and (2) only
D. (1) and (3) only

28. The table below shows the results of blood tests for the presence of antigens and
antibodies of hepatitis B virus (HBV) in four individuals.

Antigen Antibodies

Individual 1 Present Present

Individual 2 Present Absent
Individual 3 Absent Present
Individual 4 Absent Absent

Which of the following statements is incorrect?

A. Individuals 1 and 2 are infected with HBV, but only individual 1 can produce
antibodies against the virus.
B. Individual 3 has recovered from an infection and has become immune to HBV.
C. Individual 4 has no previous infection and is not immune to HBV.
D. Vaccination can confer protective effect to individuals 2 and 4 against HBV.

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 S.6 Biology Mock Examination (2021-2022)

29. The electron micrograph below shows a section of a chloroplast.

X Y

(×20, 000)

Which of the following correctly states the metabolites produced in the reactions that
occur at X and Y?

At X At Y
A. ATP NADP
B. NADP glucose
C. NADP oxygen
D. NADPH ATP

30. Which of the following combinations correctly compares the way ATP being made in
respiration and photosynthesis?

Key: ✓ = common to both  = not common to both

Electron transport chain ATP synthase Oxidation of NADH

A. ✓ ✓ ✓
B. ✓ ✓ 
C.  ✓ ✓
D.   

15 .
31. Increased grazing by herbivores in a grassland habitat can result in an increase in
diversity of plant species in the habitat. Which of the following is most likely the
explanation?

A. Few herbivores are able to eat every plant species present.

B. Some plants can regenerate quickly following damage by herbivores.
C. Damage to dominant plant species by grazing allows the survival of other
species.
D. Plant species with defences against grazing are selected.

Directions: Questions 32 and 33 refer to the diagrams below, which shows a food web
consisting of five different species (P, Q, R, S and T).

2 3 T
P R

4
S

32. Which of the following statements correctly describe the above species?

(1) P is a producer.
(2) R is a herbivore.
(3) The biomass of T is less than that of Q.

A. (1) and (2) only

B. (1) and (3) only
C. (2) and (3) only
D. (1), (2) and (3)

33. Assuming the energy input for each food chain is the same, the transfer of energy
between two trophic levels is the smallest in

A. 1.
B. 2.
C. 3.
D. 4.
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 S.6 Biology Mock Examination (2021-2022)

Directions: Questions 34 and 35 refer to the diagrams below, which shows the distribution
of four species of seaweeds down a shore. The height of each small square
represents 10% coverage.

species 1
Percentage cover of seaweeds (%)

species 2

species 3

species 4

0 10 20 30 40 50
Distance from
high tide mark high tide mark (m) low tide mark

34. What is the percentage cover of seaweed species 3 at the low tide mark?

A. 15%
B. 30%
C. 60%
D. 80%

35. Which species of seaweed is more adapted to great fluctuations in environmental

conditions?

A. 1
B. 2
C. 3
D. 4

17 .
36. After trying to observe a specimen under high-power magnification of a light
microscope, George decided to switch back to low-power. Which of the following are
the probable reasons behind?

(1) He would like to obtain a brighter image at the high-power magnification.

(2) He would like to observe a larger area of the specimen and select another part of the
specimen to observe.
(3) He would like to refocus once again as he failed to obtain a clear image at the
high-power magnification.

A. (1) and (2) only

B. (1) and (3) only
C. (2) and (3) only
D. (1), (2) and (3)

END OF SECTION A
Go on to Question-Answer Book B for questions on Section B

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