THE APEX JOINT EXAMINATIONS

Kenya Certificate of Secondary Education

231/ 2 - BIOLOGY PAPER 2 – FORM FOUR

MOCK EXAMINATIONS – JULY 2024 – 2 Hours
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Name……………………………………………………Index number………………………….…

Candidate’s Signature………………………………...Date……………………………………….
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Instructions to candidates
(a) Write your name and class number in each of the foolscaps answer sheets.
(b) Sign and write the date of the examination in the spaces provided.
(c) This paper consists of two sections; A and B.
(d) Answer all the questions in section A in the spaces provided.
(e) In section B answer question 6 (compulsory) and either question 7 or 8 in the spaces provided after
question 8.
(f) This paper consists of 10 printed pages.
(f) Candidates should check the question paper to ascertain that all the pages are printed as
indicated and that no questions are missing
(g) Candidates should answer the questions in English.

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For examiner’s use only

Questions Maximum score Candidates score
1 8
2 8
3 8
4 8
5 8
6 20
7 or 8 20
80

© The Apex Joint Mock Examinations 2024

231/2

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 SECTION A (40 MARKS)
Answer all the questions in this section in the spaces provided.
1. The diagram below shows a section through a leaf.

(a) (i) Identify the labeled part that will produce the most glucose. Explain. (2 marks)
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(ii) Explain what happens to the glucose produced in the part identified in (a) (i) above. (1mark)
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(b) Describe how carbon (IV) oxide enters the leaf. (3 marks)
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(c) Describe the processes that take place in the leaf to produce oxygen. (2 marks)
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2. Study the diagram of the mammalian ear and answer the questions that follow.

(a) Name the parts labeled X, Y and N. (3 marks)

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(b) State how the parts labelled Y are adapted to their functions. (2 marks)
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(c) (i) Besides hearing, state one other function of the ear. (1mark)
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(ii) Which of the labelled parts is responsible for the function you have stated in (c) (i) above? (1mark)
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(d) What would happen if the auditory nerve is completely nerve is completely damaged? (1mark)
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3 (a) What is advantage of an individual having heterozygous condition (1mark)
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(b) Name two disorders in man due to gene mutations. (1mark)

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(c) State two symptoms of Down’s syndrome. (2 marks)

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(d) When flies with grey bodies were crossed with flies with black bodies, all the offspring in the F1 had grey
bodies. Use the letters G and g to represent a genetic cross to show the F2 genotypes and phenotypes if the F1
were test-crossed. (4 marks)
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4. The diagram below shows part of a longitudinal section of a young root.

(a) Name the parts labeled B and C. (2 marks)

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(b) State the significance of cell A. (1mark)
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(c) Explain how water from the soil reaches tissue D. (4 marks)
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(d) State one adaptation of part D to its function. (1mark)
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5 (a) Explain two adaptations of the buccal cavity of a frog to gaseous exchange. (2 marks)
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(b) The diagram shows apparatus used to investigate breathing.

At the start, both tubes contain orange hydrogen carbonate indicator solution.
 The solution is orange when atmospheric air passes through it.
 The solution changes to red when air with less carbon dioxide passes through it.
 The solution changes to yellow when air with more carbon dioxide passes through it.
Which changes occur to the hydrogen carbonate indicator solution in tubes X and Y when a person breathes in
and out through the tube M? (3 marks)
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(c) Describe and explain what might happen to a person’s breathing as they climb up a mountain. (3 marks)

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 SECTION B (40 marks)
Answer question 6 (compulsory) and either question 7 or 8 in the spaces provided after question 8.
6. The data provided below represent the growth of a pollen tube of a certain plant species over a given time.

Time in minutes 0 30 60 90 120 150 180

Growth in millimeters 0 1.8 2.8 6.2 9.0 10.2 10.4

(a) Draw a graph of growth of pollen tube against time. (6 marks)

(b) (i) At what intervals was the growth of the pollen tube measured. (1mark)
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(ii) At what time was the length of the pollen tube 7.8mm? (1mark)
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(c) With reasons describe growth pattern of the pollen tube between:
(i) 0 to 120 minutes (1mark)
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Reason (1mark)
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(ii) 120 to 180 minutes (1mark)
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Reason (1mark)
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(d) Apart from nutrients, state two factors that affect the growth of pollen tube. (2 marks)
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(e) State two functions of the pollen tube. (2 marks)
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(f) Describe what happens when the pollen tube enters the embryo sac. (4 marks)
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7 (a) Define the following terms: (3 marks)
(i) Excretion
(ii) Egestion
(iii) Secretion
(b) Describe how urea is formed in the human body. (7 marks)

(c) Explain the role of antidiuretic hormone in homeostasis. (10 marks)

(10 marks)
8. Describe the causes and effects of water pollution
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