BIOLOGY PAPER 231/1 K.C.S.E 1997 QUESTIONS

BIOLOGY PAPER 231/1 K.C.S.E 1997

QUESTIONS

Answer all the questions in this section in the spaces provided

1. State the functions of the following cell organelles:
   1. Golgi apparatus
   2. Ribosomes
2. A student caught an animal which had the following characteristics:

   Body divided into two parts

   Simple eyes

   Eight legs

   The animal belongs to the class

3. What are the three end products of anaerobic respiration in plants?
4. State two ways in which xylem vessels are adapted to their function.
5. In an accident, a victim suffered brain injury. Consequently, he had loss of memory. Which part of the brain was damaged?
6. Oil can be applied on stagnant water to control the spread of malaria.
   1. How does this practice control the spread of malaria?
   2. Give a reason why this practice should be discouraged.
7. State three structural differences between biceps muscles and gut muscles.

8. A person was found to pass out large volumes of dilute urine frequently.

   Name the:

   1. Disease the person was suffering from
   2. Hormone that was deficient
9. State three pieces of evidence that support the theory of evolution.
10. Name a disease caused by lack of each of the following in human diet:

    Vitamin D

    Iodine

SECTION B (40 MARKS)

11. The following represents a feeding relationship in an ecosystem:

    

    1. Write down the food chains in which the guinea fowls are secondary consumers.
    2. What would be the short term effects on the ecosystem if lions invaded the area?
    3. Name the organism through which energy from the sun enters the food web.
12. A person was able to read a book clearly at arm’s length but not at normal reading distance.
    1. State the defect the person suffered from.
    2. Why was he unable to read the book clearly at normal distance?
    3. How can the defect be corrected?
13. An experiment was carried out to determine the rate of transpiration in three plants A, B, and C. Plants A and B belonged to different species while plants B and C belonged to the same species. Plant C had all its leaves removed. The three plants were of similar size and were exposed to the same environmental conditions.

    The results are shown in the graphs below:

    

    1. Suggest possible environmental conditions under which the experiment was carried out between 30 and 60 minutes.
    2. Account for the results obtained for plant C.
    3. Suggest the habitat for plant A and B. Give reasons for your answer.

       Habitat for plant A

       Habitat for plant B

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14. The diagram below represents a simplified nitrogen cycle.

15. Name the organisms that cause processes E and J.
16. Name the processes represented by F and H.
17. Name the group of organisms represented by G.

18. The equation below represents a metabolic process that occurs in the mammalian liver:

    Amino acids → Organic compounds + urea

    1. Name the process.
    2. What is the importance of the process to the mammal?
    3. What is the source of amino acids in this process?
    4. What is the difference between essential and nonessential amino acids?
19. In a breeding experiment, plants with red flowers were crossed. The produced 123 plants with red flowers and 41 with white flowers.

    (a) Identify the recessive character and give a reason.

    (b) What was the genotype of the parent plants that gave rise to the plants with red and white flowers?

20. Which letters in figures 1 and 2 represent the organs that produce female gametes?

    Figure 1

    Figure 2

21. What is the function of the structure labeled S?
22. Name the structure labeled W.
23. Which letters in figures 1 and 2 represent the structures where fertilization takes place?
24. Which letter in figure 1 represents the structure where male gametes are produced?

SECTION C (40 marks)

25. An experiment was carried out to determine the growth rates of bamboo and a variety of maize plants in two adjacent plots. The average height and average dry weight of plants from the two populations were determined over a period of twenty weeks. The data is as shown in the table below.

26. Between which two weeks did the greatest increase in weight occur in:
    1. Bamboo plants
    2. Maize plants

27. (i) Which of the two types of plants had a higher productivity by the end of the experiment?

    (ii) Give a reason for your answer in (i) above.

28. Between weeks 14 and 18, the average height of the maize plants remained constant while average dry weight increased. Explain this observation.
29. Suggest how the change in the average dry weight of bamboo and maize plants would have been at week 22 if the experiment was continued.
30. Why was it appropriate for this experiment to use:

    (i) Dry weight instead of fresh weight

    (ii) Weight and height

31. Describe how the average height and weight of the plants were determined in this experiment.

    Average height

    Average dry weight

32. Give a reason why secondary thickening does not occur in bamboo and maize plants.

33. (a) What is parasitism?

    (b) Describe how the tapeworm is adapted to a parasitic mode of life.

34. (a) What is meant by the term digestion?
35. (b) Describe how the mammalian small intestine is adapted to its function.