Name:………………………………………………………………………Index No:……………….

P530/1
BIOLOGY PAPER 1
(Theory)
2 ½ HOURS

DEPARTMENT OF BIOLOGY
UGANDA ADVANCED CERTIFICATE OF EDUCATION
INTERNAL MOCK EXAMINATIONS
BIOLOGY PAPER ONE
TIME: 2 HOURS 30 MINUTES

INSTRUCTIONS
- Answer ALL the questions.
- Write your answers to Section A on the answer sheet at the end of the Section.
- Write your answers to Section B only in the answers provided.

FOR EXAMINER’S USE ONLY

QUESTION MARKS
SECTION A: 1 – 40
SECTION B: 41
42
43
44
45
46
TOTAL

SECTION A
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1. Cholesterol is:
A. A diglyceride C. an unsaturated fat
B. A saturated fat D. a steroid

2. The unique properties of each amino acid are determined by its particular:
A. R group C. kind of peptide bonds
B. amino group D. number of bonds to other amino acids

3. The two types of secondary structures of proteins are:

A. Conjugated, alpha index C. Alpha helix, beta pleated sheet
B. Beta pleated, conjugated D. Polypeptide, alpha helix

4. The shape of an enzyme, and consequently its activity, can be reversibly altered from
moment to moment by:
A. Heat C. allosteric submits
B. Amino acid substitutions D. sulfur substitutions

5. The active site of an enzyme is formed by a few of the enzyme’s.

A. R group of the amino acids C. Carboxyl groups of the amino acids
B. Amino groups of the amino acids D. Exposed sulfur bonds

6. Which of the following forms part of a coenzyme?

A. Zn2+ B. Lipase C. Vitamin B2 D. Lysine

7. Proteins that are to be used outside the cell are synthesized:

A. in the mitochondria
B. on the rough endoplasmic reticulum
C. on the smooth endoplasmic reticulum
D. on free ribosomes

8. The mesh of fibres, such as microtubules and microfilament, that crisscross through the
cytoplasm of a cell is called the:
A. Golgi complex C. Endoplasmic reticulum
B. Cellulose D. Cytoskeleton

9. When phospolipids molecules are placed in water, they may cluster into a spherical
structure called:
A. Micelle C. Vacuole
B. Coated pit D. Centriole
10. Pressure on a plant cell wall caused by osmotic movement of water is called:
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 A. Osmotic pressure C. Ionic pressure
B. turgor pressure D. hypertonic

11. The osmotic pressure of pure water is:

A. O B. 1 C. 10 D. 100

12. Which of the following substance does not enter cells through membrane proteins or by
endocytosis?
A. O2 B. Glucose C. Proteins D. Amino acids

13. A woman without dimples mates with a man who has dimples and who is known to be
heterozygous for the trait. What is the chance that their first child will have dimples?
A. ¼ B. ½ C. ¾ D. it is certain

14. If the first child of the couple described in question 13 above had dimples then what is the
chance that their second child will have dimples?
A. No chance B. ¼ C. ½ D. ¾

15. The allele for black hair colour (B) is dominant over the allele for white hair colour (b) in
guinea pigs. A test cross between a black female and a white male produced a litter of six
black guinea pigs. The genotype of the father is:
A. unknown, due to the small sample size.
B. BB C. Bb D. bb

16. In water melons, the allele for green colour (G) is dominant over the allele for stripped
colour (g) and the allele for short shape (S) is dominant over the allele for long shape (s).
When long, stripe water melons are crossed with water melons heterozygous for both
traits, what proportion of the offspring are striped and short?
A. O B. ¼ C. ½ D.

17. When two or more nonallelic gene pairs affect the same character in the same way, this
is called:
A. Polygenic inheritance C. Total penetrance
B. Pleitropy D. additive expressivity

18. Compared to gram-negative bacteria gram positive bacteria.

A. Have more complex cell walls
B. Are more resistant to antibiotics
C. Retain the violet dye rather that the red.
D. Have less pepetidoglycan

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19. Slime molds in the division myxomycota (true slime molds) have.
A. Feeding stages consisting of solitary, individuals cells.
B. Spores that develop into flagellated gametes.
C. Pseudoplasmodia
D. Spores that develop into free living amoeboid cells

20. Which of the following structures is not diploid?

A. Sertoli cells C. Spermatids
B. Germ cells D. Oogonia

21. After ovulation the secondary oocyte enter the:

A. ovary C. Cervix
B. corpus luteum D. Oviducts

22. The acrosome of sperms is important in reproduction because it:

A. carries genetic information
B. provides energy for movement
C. carries the enzymes that facilitate fertilization
D. induces ovulation

23. During oogenesis in mammals the second meitotic division occurs:

A. after implantation C. before acrosome reaction
B. before ovulation D. after sperm enters the egg.

24. Which of the following is not a function of semen?

A. Neutraalizing the acidic medium of the vagina
B. Activation of spermatozoa
C. Destruction of bacteria in the urethral tract.
D. Nourishing the sperms.

25. Which of the following is true during fertilization in man?

A. Sperms meet the ovum in the ovary.
B. Ovum complete oogenesis immediately after fertilization.
C. Ovum completes oogenesis immediately before fertilization.
D. Only the egg nucleus and sperm nucleus fuse to form zygote.

26. The hormone controlling the ovulation and luteal phase of the human menstrual cycle is:
A. Luteinizing hormone C. Follicle stimulating hormone
B. Progesterone D. Oestrogen
27. Below the carrying capacity which is the following statements is true:
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 A. Mortality is density independent C. Population is growing exponentially
B. Natality is density independent D. Mortality is density dependent.

28. During development in birds the embryo grows in the:

A. Yolk sac C. Amnion
B. Allantois D. Chorion

29. The inter-relationship between living and non living components in a biological system is
best described as:
A. Community C. Ecosystem
B. Population D. Micro habitats

30. Which types of natural selection does artificial selected resemble:

A. Disruptive selection C. Stabilizing selection
B. Progressive selection D. Kin selection

31. Which one of the following is a compound plant tissue?

A. Parenchyma C. Epidermis
B. Xylem D. Collenchyma

32. A species whose distribution in nature is largely restricted to one locality is termed:
A. Extinct C. Endemic
B. Rare D. Vulnerable

33. During the action of an antibody, antigen can easily be clumped together because:
A. antibodies adhere to surface of the micro-organism.
B. The shape and amino acid sequence of antibodies varies
C. antibodies have complementary shapes to antigens.
D. Each antibody has two binding sites

34. The human cardiac muscle has a relatively longer refractory period so as to prevent:
A. The muscle contracting strongly.
B. The heart from pumping a lot of blood to the body tissues.
C. The muscle from developing a tetanus.
D. The muscle from developing a much higher oxygen debt.

35. Which bonds are the last to break when an enzyme is heated?
A. Disulphide C. Hydrophobic
B. Hydrogen D, Ionic

36. The lymphatic system is like the circulatory system in that they both:
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 A. Have nodes that filter our pathogens C. Have capillaries
B. Have a network of arteries D. Are open systems

37. Gall stones are as a result of precipitation of which components of bile?

A. Bilirubin C. Cholesterol
B. Bile acids D. Bile salts

38. Most carbondioxide from catabolic reactions is released during:

A. Glycolysis C. Lactate fermentation
B. The Kreb’s cycle D. Oxidative phosphorylation

39. Two organisms that use the same resources when those resources are in short supply are
said to be:
A. Predators C. Mutualists
B. Competitors D. Commensals

40. The appropriate unit for defining and measuring genetic variation in an area is the:
A. individuals C. community
B. population D. ecosystem

ANSWER SHEET TO SECTION A

1. 11. 21. 31.

2. 12. 22. 32.

3. 13. 23. 33.

4. 14. 24. 34.

5. 15. 25. 35.

6. 16. 26. 36.

7. 17. 27. 37.

8. 18. 28. 38.

9. 19. 29. 39.

10. 20. 30. 40.

SECTION B
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41. The figure represents three types of distribution in nature:
A B C

(a) Name the pattern of distribution. (03mks)

(i) A:………………………………………………………………………………………………………………
(ii) B:………………………………………………………………………………………………………………
(iii) C:………………………………………………………………………………………………………………
(b) Explain why the following patterns of distribution are rare: (03mks)
A and B
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(c) Explain why type C distribution is common in nature. (02mks)
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(d) State one advantage and one disadvantage of type C distribution in animals.
(02mks)
Advantage
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Disadvantage
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42. (a) What is meant by carrying capacity of the environment? (02mks)
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(b) Give two major factors that determine the carrying capacity of environment.
(02mks)
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(c) Under which circumstances may a population exceed its carrying capacity?(03mks)
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(d) State the environmental indicators for a population that has exceeded its carrying
capacity. (03mks)
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43. The movement of blood through blood vascular systems of mammals is as a result of
pressure gradients.
(a) Describe how the pressure gradients are produced in the vascular systems.
(04mks)
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 (b) Explain a physiology advantage of a closed double circulatory system to an
organism. (03mks)
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(c) How is a mammalian cardiac muscle suited for its function? (03mks)

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44. (a) What do you understand by the following types of synapses. (03mks)
(i) Axodendritic
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(ii) Somatic
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(iii) Electrical
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 (b) Briefly describe impulse transmission across a chemical synapse. (07mks)
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45. (a) Describe what occurs during the following phases of spermatogenesis in human
male.
(i) Multiplication (03mks)
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(ii) Maturation (03mks)
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(b) State 3 advantages of internal fertilization. (02mks)
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(c) Explain the acrosome reaction. (02mks)
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46. (a) What is polyploidy? (02mks)
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(b) Explain how polyploidy may cause formation of new species. (04mks)
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(c) Explain why Polyploidy is more likely to occur in plants than animals. (04mks)
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END

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