(a). Name the gases involved in the photosynthesis of a plant.
(b) State one role each of the gases named in 2 (a).
(c) (i) What is a variegated leaf?
(ii)Which part of the variegated leaf would test positive when treated with iodine solution?
(iii) State two reason for the answer in 2(c) (ii).
(iv) Name one mineral element required by plants for the formation of the part that would test positive in 2(c)(ii).
(d) The table below indicates different methods by which organism obtain food. Place the following organism under the heading in the table below: Human, Mushroom, Venus flytrap, Waterleaf plant, Tapeworm, Elephant grass, Housefly, Lichen, Spirogyra, Rhizopus.
Mode of Nutrition
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Parasitic |
Symbiotic |
Saprophytic |
Autotrophic |
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(a) Gases involved in photosynthesis: carbon dioxide (CO2) and oxygen (O2).
(b) Role of each gas
- Carbon dioxide: it is a raw material that is taken in and used to manufacture carbohydrate (glucose).
- Oxygen: it is the gas given off (released) as a by-product of photosynthesis.
(c)(i) What is a variegated leaf?
A variegated leaf is a leaf that has both green and non-green (white or yellow) patches, because chlorophyll is present only in the green parts.
(c)(ii) Only the green part of the leaf tests positive (turns blue-black) with iodine solution.
(c)(iii) Two reasons
- Only the green part contains chlorophyll, which traps light energy for photosynthesis.
- Therefore only the green part manufactures and stores starch; the non-green part has no chlorophyll and cannot make food.
(c)(iv) Mineral element needed to form chlorophyll: magnesium (nitrogen is also acceptable).
(d) Classification of the organisms by mode of nutrition
| Holozoic | Parasitic | Symbiotic | Saprophytic | Autotrophic |
|---|
| Human, Housefly | Tapeworm | Lichen | Mushroom, Rhizopus | Venus flytrap, Waterleaf plant, Elephant grass, Spirogyra |
(a) Gases involved in photosynthesis: carbon dioxide (CO2) and oxygen (O2).
(b) Role of each gas
- Carbon dioxide: it is a raw material that is taken in and used to manufacture carbohydrate (glucose).
- Oxygen: it is the gas given off (released) as a by-product of photosynthesis.
(c)(i) What is a variegated leaf?
A variegated leaf is a leaf that has both green and non-green (white or yellow) patches, because chlorophyll is present only in the green parts.
(c)(ii) Only the green part of the leaf tests positive (turns blue-black) with iodine solution.
(c)(iii) Two reasons
- Only the green part contains chlorophyll, which traps light energy for photosynthesis.
- Therefore only the green part manufactures and stores starch; the non-green part has no chlorophyll and cannot make food.
(c)(iv) Mineral element needed to form chlorophyll: magnesium (nitrogen is also acceptable).
(d) Classification of the organisms by mode of nutrition
| Holozoic | Parasitic | Symbiotic | Saprophytic | Autotrophic |
|---|
| Human, Housefly | Tapeworm | Lichen | Mushroom, Rhizopus | Venus flytrap, Waterleaf plant, Elephant grass, Spirogyra |
