Biology Paper 2 Questions - Alliance Girl's High School Mock December 2020

Instructions to candidates;

1. Write your name, index number, date and sign on the spaces provided above.
2. Answer ALL questions in section A.
3. In section B, answer question 6 (compulsory) and either question 7 or 8.
4. Candidates should answer the questions in English.

For Examiners' Use Only

QUESTIONS

SECTION A: 40 marks
Answer ALL questions in this section.
1. The diagrams below represent two plant cells A and B placed in two different solutions. Study the diagrams and answer questions that follow:

1. Identify the nature of solution into which each cell was placed, (2 marks)
   A .........
   B............
2. Name the physiological process responsible for the observed results.(1 mark)
3. Give the correct biological term used to describe cell A.(1 mark)
4. Describe what would happen if a red blood cell was placed in the solution in which cell B was placed(2 marks)
5. Explain why freshwater amoeba do not burst when placed in distilled water. (2 marks)

2. 

1. The diagram below illustrates the arrangement of bones and muscles in the human arm.
   
   
   1. Name the bones labelled K and L. (2 marks)
   2. Explain how the upward movement of the lower arm is brought about by the bones and muscles shown on the diagram above.
      (3 marks)
2. State three ways in which support is brought about in a leaf. (3 marks)

3.

1. What is meant by the term linked genes? (1 mark)
2. Haemophilia is a genetic condition transmitted through a recessive gene linked to X chromosome. The normal gene may be represented by X^H
   1. What is the genotype of a haemophilic female? (Imark)
   2. A woman who is a carrier for the haemophilia gene marries a normal man. Work out the phenotypic ratio for their offspring. (4 marks)
   3. Haemophilia is more common in males than in females. Explain this phenomenon. (2 marks)

4. The diagram below shows a set up to investigate a factor necessary for germination

1. Name the factor under investigation. (1 mark)
2. State the role of pyrogallic acid in the set up. (1 mark)
3. Which type of respiration is taking place in the beans? (1 mark)
4. Write a word equation for the process named in (c) above. (1 mark)
5. Explain why plants can only carry out the above respiration process for a short while. (1 mark)
6. State other three factors necessary for germination. (3 marks)

5.

1. Distinguish between pyramid of numbers and pyramid of biomass. (2 marks)
2. Give three reasons for loss of energy from one trophic level to another in a food chain. (3 marks)
3. Describe how the belt transect can be used in estimating the population of a shrub in a grassland. (3 marks)

SECTION B (40 MARKS)
Answer 6 (compulsory) and either question 7 or 8 in the spaces provided
6.

1. An experiment was carried out to investigate the population of a certain micro-organism.
   Two petri-dishes were used into the petri-dish labeled M 60cm³ 'of a culture medium was placed while 30cm³ of the same culture medium was placed in petri-dish labeled N. Equal numbers of the micro-organisms were introduced in both petri-dishes. The set-ups were then incubated at 35^οc. The number of micro-organisms in each petri-dish was determined at irregular intervals for a period of 60 hours. The results were as shown in the table below
   

   Relative number of M micro-organisms	M	40	40	180	280	1200	1720	1600	1840	1560	600
   	N	40	40	120	200	680	560	560	600	600	400
   Time in hours		0	5	10	15	23	30	35	42	45	60

   1. On the same axes, draw the graphs of relative number of micro-organisms against time on the grid provided. (7 marks)
   2. After how many hours was the difference between the two populations greatest? (1 mark)
   3. Work out the difference of the two populations at 50 hours. (2 marks)
   4. With a reason state the effect on the population of micro-organisms in petri-dish M if the temperature was raised to 60°C after 20 hours. (2 marks)
   5. Account for the shape of the curve for population in petri-dish N between 46 hours and 59 hours. (3 marks)
2. Name three biotic factors that influence distribution of living organisms in an ecosystem (3 marks)
3. Using an example, describe what is carrying capacity of an ecosystem? (2 marks)

7. Describe the adaptations of the ear to its functions.
8. Discuss evidences of organic evolution.  (20 marks) (20 marks)