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.
Explanation
SECTION A
1. (a) Iron - Required for formation of chlorophyll
(b) Phosphorus - Formation of nucleic acids, enzymes, controls cell division
(c) Calcium - For cel formation, neutralization of some organic acids
(d) Potassium - Required for cell formation and regulation of cell activities
2. (a) Plant parasite Cassytha, Mistletoe
(b) Saprophytic plant - Rhizopus, mucor
(c) Carnivorous plant - Bladderwort, drosera, Venus plant.
3. Structural modifications of named birds that feed on (a) Nectar,: (i) The weight is light (ii) The beak is long and pointed
(iii) The name of the bird is Sunbird (b) Flash: (i) The beak is sharp and curved (ii) eyes are keen and bulging (iii) The claws are sharp curved (iv) The name of the bird is Hawk.
4. Principles on which the use of quadrat for determining population are based: (i) The quadrant is used for stationary organisms
(ii) At least ten throws must be made
(iii) The size of the quadrat depends on the organism being sampled.
5. (a) Deoxyribonucleic acid or ribonucleic acid (b) Phosphorus, carbon, hydrogen, nitrogen, sulfur
6. (a) Diagram B (b) (i) The hair stands erect (ii) There is no sweating (iii) Blood vessels constrict (iV) The erector muscle of the hair contracts.
7. Using high temperature (auto clearing) (i) By the application of salt (ii) By the user of antibiotics (iii) By the use of antiseptic.
8. (a) Direction B (b) Direction B (c) Experiment to show phototropism of shoot to unilateral supply of light OR. To show the effect of auxin on plant growth.
SECTION B
9. (a) The similarities are: (choose any two from the following: (1) Presence of epicarp, mesocarp and endocarp (2) Seed present (3) Spherical in shape (4) Scar or point of attachment or remains of. style present (ii) Differences. (Choose any four from the following):
|
Orange |
Palm fruit |
Coconut |
|
(a) Small seed. |
Large seed |
Large seed |
|
(b) Has soft endocarp |
Has hard endocarp |
Has hard endocarp |
|
(c) Possesses many seeds |
Has one to three seeds |
Has one seed |
|
(d) Has juicy soft and fleshy mesocarp |
Fibrous |
Spongy and fibrous for older ones |
|
(e) Has rough epicarp |
Has smooth epicarp |
Has smooth epicarp |
(b) Drawing of longitudinal section of orange fruit
10. (a) Specimen C is toad or frog, specimen D is bird or chicken or cockerel (b) Differences (Choose any three from the following answers)
|
Specimen C |
Specimen D |
|
(i) Bulging eyes |
No bulging eyes |
|
(ii) Has no tail |
Has tail |
|
(ii) Scales present |
No Scales present |
|
(iv) No-beak |
Has beak |
|
(V) Has digits without claws |
Has digit with claws |
| (vii) Absence of feathers or wings |
Presence of feathers or wings |
|
(VIl) No nect |
Has a short nect |
(d) (Choose any four from the following) (i) Possesses webbed hind limbs for swimming (ii) Possesses big eyes for looking over the water when the whole body is submerged (iii) Has a streamlined shape, for swimming through the water easily (iv) Position of the nostril, helps the animal to breath atmospheric air while the body is still submerged (v) Dark dorsal side and lighter ventral side. The dark dorsal side enables the ventral side. animal to blend with the dark floor when viewed from above, while the lighter ventral side blends with the sky when viewed from underneath (vi) Nictating membrane protecting the eye when submerged in water.
Working: 20 - 10cm|(^3\) in 10 - 5 minutes
5 minutes = 10cm\(^3\)
(i) 12th minute of 25°C
1 minute = 10/5 cm\(^3\)
7 minutes = 10\5 X 7/1 cm\(^3\),
= 14cm\(^3\)
5 minutes = 16.5cm\(^3\)
1 minute = 16.5/5 2/1cm\(^3\)
2 minutes = 6.6 cm\(^3\)
40+ 6.6cm\(^3\) = 46.6cm\(^3\) or 46.5cm\(^3\) if read from graph
11. (a) (b) (i) 25°C gave the best ptyalin action (ii) Increasing temperature above 25°C reduces ptyalin action (iii) Amount of starch hydrolyzed increases with time
(c) 7th minute at 15°C
(iii) 24th minute at 45°C
worked out as in (c) (ii)
25 - 20 i.e
5 minutes = 19 - 17 = 2.0cm\(^3\)
1 minute = 2/5cm\(^3\)
4 minutes = 2/5 X 2/1cm\(^3\), i.e 1.6cm\(^3\)
in 24th minutes 17 + 1.6cm\(^3\) = 18.6cm\(^3\)
or 18.5 / 18.6cm\(^3\) if read from the graph.