Biology 2018 Theory
1.(a) Explain briefly how the structure of each of the following cells relate to their functions:
(i) Sperm cell
(ii) Palisade cell.
(b) Make a drawing, 8cm to -10cm long of the front view of the female reproductive system in humans and label fully.
(c) State two differences between reproduction in mammals and in amphibians.
(d) State two methods of birth control in humans.
2. (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.
| Holozoic | Parasitic | Symbiotic | Saprophytic | Autotrophic |
3. (a). Explain briefly the following terms:
(i) Renewable natural resources
(ii) Non -renewable natural resources;
(b) Give two examples each of:
(i) Renewable natural resources
(ii) Non -renewable natural resources
(c) State five ways of conserving forests
(d) State four effects of adding animal manure to garden soil.
(e) Give the possible genotypes in humans;
4. a. Explain briefly the following terms:
i. gene;
ii. Hybrid;
iii. Trait.
(b) Two heterozygous yellow flowers are crossed. Using a genetic diagram, state the phenotypic and genotypic ratios of the first filial generation.
(c) State four transmitted characters in plants.
5 (a)(1) Explain briefly chemosynthesis as a mode of nutrition.
(ii) Give two examples of organism that carry out chemosynthesis.
(b) List three gases in the atmosphere with their percentage composition.
| Gases in the atmosphere | Percentage composition |
(c) (i) State four characteristics of a salt marsh habitat.
(ii) Explain briefly how plants are modified for anchorage in a salt marsh habitat.
(d) (i) List four bacterial disease associated with poor food hygiene.
(ii) State three effects of poor food hygiene.
(e) A person was involved in a car accident and became unconscious due to excessive blood loss. Explain briefly how the blood lost could be restored.
(f) State three differences between tillage and bush burning as farming practices.
| Tillage | Bush burning |
