Candidate’s Name: ….…………………………………………………………………….

Signature: …………………………………………………………………………………..
BIO P530/1
BIOLOGY
PAPER 1
SET I 2022
2 ½ hours
Uganda Advanced Certificate of Education

Resource Examinations, 2022

BIOLOGY (THEORY)

PAPER 1

2 HOURS 30 MINUTES

INSTRUCTIONS TO CANDIDATES
This paper consists of sections A and B. Answer all questions in both sections.
SECTION A:
Answers to this section must be written in boxes provided.
SECTION B.
Answers to this section should be written in the spaces provided and not anywhere else.

For Examiner’s use only

Section Marks
A: 1-40
B: 41
42
43
44
45
46
Total

Page 1 of 13
 SECTION A (40 marks)
Write the letter corresponding to the right answer in the box provided. Each question in
this section carries one mark.
1. Oxidative phosphorylation occurs…….
A. Between hydrogen acceptor molecules and cytochrome molecules of electron transport chain
on cristae in mitochondria.
B. Between hydrogen acceptor molecules and cytochrome molecules of electron transport chain
in chloroplasts.
C. Inner membrane cytochrome molecules on cristae infolding in mitochondria.
D. Grana of chloroplast.

2. Carbon dioxide functions as a greenhouse gas by

A. Interfering with water’s ability to absorb heat
B. Increasing the random molecular motion of oxygen
C. Allowing radiation from the sun to reach the earth and absorbing the reradiated heat
D. Splitting into carbon and oxygen and increasing the rate of cellular respiration.

3. Which of these is not consistent with evolutionary theory?

A. All living organisms share a common ancestor
B. The environment affects which organisms survive to reproduce
C. Natural selection always favors the same traits regardless of the environment
D. Species change over time.

4. The path of a sperm during fertilization is

A. Follicle cells, egg plasma membrane, zona pellucida
B. Egg plasma membrane, zonapellucida, follicle cells
C. Zona pellucida, follicle cells, egg plasma membrane
D. Follicle cells, zona pellucida, egg plasma membrane.

5. Facilitated diffusion and active transport both require……

A. Adenosine triphosphate
B. Protein carriers
C. Unidirectional movement of solutes.
D. That the solutes moved be soluble in liquids.

6. The substances which lowers the surface tension in alveoli to ease their flexing during ventilation
movements of the chest is…
A. Mucus

Page 2 of 13
 B. Tissue fluid
C. Surfactant
D. Pleural fluid

7. Which of the following does not occur during cyclic photophosphorylation?

A. Oxidation of chlorophyll
B. Production of NADH
C. Production of ATP
D. An electron transport system.

8. The homeostatic reaction glycogen to glucose during stress is stimulated by the hormone…
A. Insulin C. Cortisol
B. Glucagon D. Thyroxin

9. During support in flowering plants, the following forces are experienced except….
A. Tension C. Thrust
B. Shear stress D. Compression

10. Which of the following hereditary characteristics is known to be sex limited?

A. Haemophilia C. Albinism
B. Baldness D. Gap between teeth (diastema)

11. Which of the following does not play part in regulating the salt concentration of mammalian
blood?
A. Kidney C. Liver
B. Skin D. Pituitary gland

12. Viruses cannot reproduce outside a living cell because…

A. Not all of them contain DNA
B. They are too small to reproduce.
C. They are unable to synthesize their own DNA
D. They are unable to absorb raw materials from the surroundings.

13. In order to survive in the sea, a marine fish

A. Loses water by osmosis and absorbs salts
B. Swallows water and absorbs salts
C. Swallows water and extrudes salts
D. Gains water by osmosis and extrudes salts.

Page 3 of 13
14. Which of the following mineral elements is not required by plants?
A. Copper C. Iodine
B. Iron D. Zinc

15. Monosomy and trisomy are genetic abnormalities that usually arise due to….
A. Polyploidy C. Non-disjunction
B. Crossing over D. Lack of cytokinesis

16. Sensitivity of the uterus to oxytocin is increased in a human female by a hormone

A. Progesterone C. Prolactin
B. Oestrogen D. Luteinizing hormone

17. Development of a seed from an unfertilized egg is called…

A. Viviparity C. Apospory
B. Apogamy D. Parthenocarpy

18. Which of the following is the function of helper T- cell in the immune response?
A. Activates B cells C. Attacks antigens
B. Produces antibodies D. Suppresses B cells

19. Haemolytic disease of the new born usually occurs when…

A. Rh- mother bears Rh+ foetus C. O+ mother bears A+ foetus.
B. Rh+ mother bears Rh- foetus D. O+ mother bears A- foetus.

20. The potentiality for the replication of DNA depends on…

A. Hydrogen bonds between the bases C. Covalent bonds between bases
B. High energy bonds between phosphate D. High molecular weight.
groups

21. Patients with diabetes mellitus have frequent urination and increased thirst because…
A. Less water passes from the glomerulus to the bowman’s capsule
B. More water is driven from the glomerulus to bowman’s capsule than normal
C. More salt is reabsorbed at the proximal convoluted tubules
D. Increased glucose in the urine increases its osmorality and less water is reabsorbed by blood.

22. Skeletal muscle contraction is normally triggered by release of neurotransmitter at a synapse that
A. Causes high level of oxygen and sugar to be released by sarcolemma
B. Causes actin and myosin to slide past each other
C. Causes flow of calcium ions that attaches to actin filaments exposing the myosin binding sites

Page 4 of 13
 D. Causes flow of calcium ions that release ATP which then causes actin filaments to slide past
myosin filaments.

23. According to evolutionary history the first animals to evolve flight as a means of locomotion
were…
A. Mammals C. Insects
B. Birds D. Reptiles

24. The pigment molecules of a chloroplast are located within the

A. Thylakoid membranes C. Intrathylakoid space
B. Inner membranes D. Intermembrane space

25. Some animals appear to spend time and energy helping others of their species. This type of
behaviour is
A. Socialism C. Territoriality
B. Mutualism D. Altruism

26. During meiotic cell division which of the following events occur during synapsis?
A. Random separation of homologous chromosomes.
B. Replication of DNA
C. Mixing up of half the maternal and paternal chromosomes.
D. Pairing up of homologous chromosomes.

27. Fixed action patterns of behaviour are predictable stereotyped behaviour responses due to…
A. Habituation C. Insight
B. Imprinting D. Innate behaviour

28. Which of these best describes development?

A. Cells divide and become large
B. Cells become specialized in structure and function
C. Body parts are shaped and patterned into a specific form
D. Organs and systems form

29. Some species that appear to occupy the same niche are able to co-exist because of…
A. Habitat fragmentation
B. Resource partitioning
C. Gause’s exclusion principle
D. Competition

Page 5 of 13
30. Which one of the following is the main form of photosynthetic product transported through the
phloem?
A. Starch C. Sucrose
B. Amino acids D. Glucose

31. High carbon dioxide concentration in respiring tissues is important because it causes
A. Local vasodilation, allowing more blood into the tissue
B. Low pH in the tissues leading to unloading of oxygen
C. Local vasoconstriction creating high blood pressure
D. Have a higher proportion of hydrogen atoms.

32. Compared to carbohydrates, fats have higher energy value because fats
A. Have long chains of fatty acids
B. Are more compact in structure
C. Have a higher proportion of carbon atoms
D. Have a higher proportion of hydrogen atoms.

33. When a man is attacked by a pathogen that secretes antigens, his body secretes antibodies. This
type of immunity is called…
A. Passive immunity C. Natural immunity
B. Active immunity D. Artificial immunity

34. Cells with important secretory functions have well developed…..

A. Mitochondria C. Centrioles
B. Lysosomes D. Golgi body

35. The trophic level that has the least amount of energy is
A. Producer C. Primary consumer
B. Decomposer D. Secondary consumer

36. Which of the following human cells contains only non-homologous chromosomes?
A. Hepatocytes C. Chondrocytes
B. Erythrocytes D. Spermatozoa

37. Which one of the following occurs when arterial pressure fails too much?
A. Stretch receptors are stimulated
B. Cardiac output decreases
C. Peripheral blood vessels dilate
D. Stretch receptors are not stimulated

Page 6 of 13
38. Which of the following causes the closure of aortic valves during cardiac cycle in mammalian
heart?
A. Filling of atria with blood
B. Ventricular pressure rising above aortic pressure
C. Ventricular pressure falling below aortic pressure
D. Contraction of ventricles.

39. Gametes in gametophyte generation of a moss are formed by

A. Meiosis 1 C. Meiosis II
B. Mitosis D. Meiosis I and II

40. Which one of the following is not an essential force during flight in birds?
A. Compressional force C. Driving force
B. Sinking force D. Lift force

Section B (60 marks)

41. a) Figure 1 below shows the relationship between substrate concentration and the initial rate
of an enzyme-catalyzed reaction under different conditions.
(A=No inhibitor, B=Competitive inhibitor and C=Non-competitor inhibitor).

Fig.1

i) Suggest why the initial rate of the reaction was measured in each case. (2 marks)
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………

Page 7 of 13
 ii) Explain;
The shape of curve A (2 marks)
………………………………………………………………………………………………………
………………………………………………………………………………………………………
………………………………………………………………………………………………………
………………………………………………………………………………………………………
The difference between the rate of reaction of curve B and curve C. (2 marks)
………………………………………………………………………………………………………
………………………………………………………………………………………………………
………………………………………………………………………………………………………
………………………………………………………………………………………………………
………………………………………………………………………………………………………
b) Figure 2 represents a metabolic pathway controlled by enzymes e1, e2, e3 and e4.

Fig.2
i) Name the type of control mechanism which regulates the production of compound Z. (1
mark)
……………………………………………………………………………………………………………
ii) Explain how an excess of compound Z will inhibit its further production. (3 marks)
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………

42. a) State two locations in the body of a mammal and the importance of the tissues in these
locations.
i) Pavement/squamous epithelium. (4 marks)
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
Page 8 of 13
 ……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
ii) Ciliated epithelium (4 marks)
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
b) State two structural differences between the epidermis of a mammal and the epidermis of
the plant leaf. (2 marks)
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
43. The number of lichen species growing along a 20km transect from the city center was recorded
at 1 km intervals. The results are presented in the figure below.

a) What is the relationship between number of lichen species and distance from city centre?
(2 marks)
………………………………………………………………………………………………………
………………………………………………………………………………………………………
………………………………………………………………………………………………………

Page 9 of 13
 b) Explain the relationship described above in (a) (5 marks)
………………………………………………………………………………………………………
………………………………………………………………………………………………………
………………………………………………………………………………………………………
………………………………………………………………………………………………………
………………………………………………………………………………………………………
………………………………………………………………………………………………………
………………………………………………………………………………………………………
………………………………………………………………………………………………………
………………………………………………………………………………………………………
………………………………………………………………………………………………………
c) Briefly describe three ways in which nitrogen is incorporated into a food chain. (3 marks)
………………………………………………………………………………………………………
………………………………………………………………………………………………………
………………………………………………………………………………………………………
………………………………………………………………………………………………………
………………………………………………………………………………………………………

44. In a school, students were asked to roll their tongues. The results obtained showed that out of
450 students, 378 were rollers and the rest non-rollers. The ability to roll one’s tongue is
determined by a dominant gene R and the lack of this ability is due to a recessive gene r.
a) Determine the total number of the R and r alleles in the school. (6 marks)
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
b) State the Hardy-Weinberg principle. (2 marks)

Page 10 of 13
 ……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
c) Name one example in each of the following abnormalities of importance to man. (2 marks)
i) Chromosome number abnormality.
………………………………………………………………………………………………………
ii) Gene mutation.
………………………………………………………………………………………………………
45. a) Non-sexual reproduction produces offsprings identical with the parent whereas sexual
reproduction produces variations. Under what circumstances does;
i) Non-sexual reproduction produces offsprings that vary. (2 marks)
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
ii) Sexual reproduction produces identical offsprings. (2 marks)
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
b) explain two ways in which the placenta is adapted to provide nutrients to a developing fetus.
(4marks)
………………………………………………………………………………………………………………
………………………………………………………………………………………………………………
………………………………………………………………………………………………………………
………………………………………………………………………………………………………………
………………………………………………………………………………………………………………
………………………………………………………………………………………………………………
………………………………………………………………………………………………………………
d) What is the role of the placenta in maintaining a pregnancy? (2 marks)
……………………………………………………………………………………………………………..
……………………………………………………………………………………………………………..
……………………………………………………………………………………………………………..

Page 11 of 13
46. Seedlings from 100g of maize seeds were grown in the dark for 10 days. The seedlings were
then analyzed and compared with 100g of ungerminated maize seeds. Table 2 below shows
the results obtained.
Dry mass of Dry mass of
ungerminated seedlings after 10
seeds days
Cellulose 2g 5g
Starch 63g 9g
Other organic 13g 27g
material 2g 4g
Ash
Total dry mass 80g 45g

a) Why is dry mass used for comparison? (1 mark)

……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
b) How would one ensure that the drying process had been completed? (1 mark)
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………

c) Explain the decrease in the total dry mass of the seedlings. (3 marks)
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
d) Why did the seedlings contain more cellulose than the ungerminated seeds? (1 mark)
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
e) Explain the relationship between starch and other organic materials in both ungerminated
seeds and germinated seeds. (4 marks)
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………

Page 12 of 13
……………………………………………………………………………………………………………
……………………………………………………………………………………………………………

Page 13 of 13