SECTION A

Answer all the questions in both sections

1. State the importance of the following elements to plants: (a) iron: (b) phosphorus (c) calcium (d) potassium

2. Give one example each of the following (a) plant parasite (b) saprophytic plant (c) carnivorous plant.

3. List two structural modifications each of one named bird which feeds on: (a) nectar, (b) flesh.

4. State three principles on which the use of the quadrat for determining population density is based on

5. (a) Name the nucleic acid that caries inherited traits (b) Name four elements found in the named nucleic acid.

6. Diagrams A and B below represent the reaction of some structures in the mammalian skin to different environmental conditions.

Use them to answer questions (a) and (b)

 

(a) Which of the diagrams represents tne reactions of the skin to cold condition? (b) List four observations from the diagrams to support your answer.

7. State three methods of controlling growth of micro- organisms.

8. In an experiment it was found that auxin was concentrated more on the shaded side of the shoot as shown in the diagram below

Use the diagram to answer questions (a) to (c): 

(a) From which direction did light reach the shoot? (b) Towards which of the directions, side A or side B will the tip grow? (c)Suggest a title for this experiment. Layer of trapped air Layer of- trapped air.

                                                                                                SECTION B

Answer all the questions

 9 Examine specimens A and B carefully, (a) State: (i) two similarities (ii) four differences. In structure between them (b) Make a labeled drawing 6-8 cm wide of the cut surface of specimen A.

10. (a) identify specimens C and D without giving reasons for your answer.

(b) In a tabular form state three differences in external features between specimens C and D.

(c) Remove a quill feather from specimen D and label it D. Make a fully labeled diagram 10 to 20 cm long of specimen D

(d) Explain how four observable features of specimen C adapt the organism to life in water. Shoot.

11. The amount of starch hydrolyzed by the enzyme ptyalin over a period of time at three different temperature are given in the table below

Time in Minutes	Volume of Starch hydrolyzed at different Temperature
	15°C                                 25°C                           45°C
5	10.0cm\(^3\)                    21.5cm\(^3\)                4.0cm\(^3\)
10	20.0 cm\(^3\)                    40.0 cm\(^3\)              6.5cm\(^3\)
15	30.0 cm\(^3\)                    56.5cm\(^3\)               10.0cm\(^3\)
20	40.0 cm\(^3\)                     68.5cm\(^3\)               17.0cm\(^3\)
25	50.0 cm\(^3\)                     70.0cm\(^3\)               19.0cm\(^3\)

(a) Placing time on the horizontal axis and the amount of starch hydrolyzed on the vertical axis, plot the date given for the different temperatures on the sam graph (b) From the graph deduce the effect(s) of temperature on the action of ptyalin on starch (C) Calculate the amount of starch hydrolyzed at the (i) 7th minute at 15°C (ii) 12th minute at 25°C (i) 24th minute at 45°C.