Haemophilia is a sex linked disorder due to a recessive gene. A carrier woman married a normal man. Let H represent gene for normal condition and h to represent gene for haemophiliac condition.
(a) State the genotypes of ; (2 marks)
(i) Man.
(ii) Woman
(b) (i) Using a punnet square, show the genotypes of the children resulting from this marriage. (3 marks)
(ii) State the probability of getting a carrier daughter. (1 mark)
(c) Give an explanation why haemophilia is more common in males than in females. (2 marks)

The figure below shows a germinating seedling.

(a) Name the parts labelled. A,B C (3 marks)
(b) Give three important environmental conditions that are necessary for seed germination and state why they are important. (3 marks)
(c) The part labelled D was removed from the above seedling three months later. After a few daysthe plant became bushy with several lateral branches.
(i) What is this phenomenon called? (1 mark)
(ii) Why did the removal of the stem tip result in a shorter plant with bushy growth? (1 mark)

The diagram below shows a set-up that was used to demonstrate fermentation.

The glucose solution was boiled; then allowed to cool before adding the yeast suspension.
Oil was then added on top of the mixture.
(a) Why was the glucose solution boiled before adding the yeast suspension? (1 mark)
(b) What was the importance of cooling the glucose solution before adding the yeast suspention? (1 mark)
(c) What was the use of the oil in this experiment? (1 mark)
(d) Give two reasons why accumulation of lactic acid during vigorous exercise lead to anincrease in heart beat. (2 marks)

(e) Other than carbon (IV) oxide, name the other products of anaerobic respiration in plants. (2 marks)
(f) Suggest a control for this experiment. (1 mark)

The diagram below represents a section through the mammalian ear. Study it and answer the questions that follow.

(a) Name the structures labelled H and J. (2 marks)
(b) State how the structures labelled H, M and N are adapted to their functions. H,M,N (3 marks)
(c) State what would happen if the structure labelled K was completely damaged? (1 mark)
(d) Name the fluid contained in structure N. (1 mark)
(e) Apart from hearing, state the other role performed by the human ear. (1 mark)

In a physiological experiment, starch, protein, diastase and sodium chloride (common salt) were added to water and put inside a visking tubing. The visking tubing was then placed in a water bath maintained at a temperature between 35^oC and 40^oC. The set-up was as shown in the diagram below.
The following observations were made after the procedures indicated.

(a) Name the process by which salt moved into the water in the beaker from the visking tubing. (1 mark)
(b) (i) Name the food substance responsible for the brown colour observed after one hour both in the beaker and visking tubing
when solutions were boiled with Benedict’s solution. (1 mark)
(ii) Account for the observation in b(i) above. (3 marks)
(c) (i) Name the food substance tested with sodium hydroxide followed by copper sulphate solutions. (1 mark)
(ii) Account for the absence of the food substance named in c(i) above in the beaker after1 hour. (1 mark)
(d) After one hour, the visking tubing was firm. State the term used to describe this state. (1 mark)

In an experiment to investigate the effects of light intensity on the rate of photosynthesis, a
shoot of Elodea (water weed) was used. The shoot was immersed in 2% sodium hydrogen carbonate
solution maintained at 150C in an apparatus which allowed for collection of a gas evolved from
the shoot. The gas given off was collected for five minutes at each light intensity and its volume
recorded as shown below.

(a) Using the data given in the table, plot a graph of gas evolved against light intensity. (6 marks)
(Graph on the next page)
(b) Account for the rate of gas evolved between;
(i) 1 - 18 arbitrary units. (3 marks)
(ii) 26 - 46 arbitrary unts. (2 marks)
(c) Explain why a green leaf is normally tested for the presence of starch instead of glucose. (2 marks)
(d) How is the dry mass of a leaf determined? (3 marks)
(e) Describe how the chloroplast is adapted to its function. (4 marks)

(a) State four characteristics of gaseous exchange surfaces. (4 marks)
(b) Explain the starch-sugar interconversion theory of opening and closing the stomata in plants. (16 marks)

Discuss the various evidences which show that organic evolution has taken place.