(a) What is photosynthesis?
(b) List: (i) four external factors
(ii) two internal factors; that affect the rate of photosynthesis.
(c)(i)List the major products of the light dependent stage of photosynthesis.
(ii)State the importance of each of the products listed in (c)(i) above.
(d)(i) Explain why there are no green plants at the lower depths of some lakes.
(ii) State why decomposers are important to flowering plants.
Explanation
(a) Photosynthesis: The process by which green plants; manufacture/ synthesize their food/organic compounds; from carbon dioxide and water; in the presence of sunlight/solar energy; giving off oxygen as a byproduct. OR
(b) (i) External Factors: Light intensity/sunlight; carbon dioxide concentration; temperature; pollution; water
(ii) Internal factors: Hormones; chlorophyll/presence of ehiorophyll/ebloroplast; enzymes; number/state of stomata
(c)(i) Major products of light-dependent stage of photosynthesis: - ATP (Adenosine triophosphate)/energy, -H+ (Hydrogen ion), - OH- (Hydroxyl ion), - NADPH2 (reduced nicotinamide adenine dinucleotide phosphate), - 0² (oxygen gas).
(ii) Importance of the products: -ATP to generate energy for the dark stage reaction, - 2H+ NADP→ NADPH2, - 0H- (Hydroxyl ion)→ H2O, O2 gas, NADPH2 - to generate hydrogen ions/to reduce carbon dioxide /C02 to form carbohydrate in the dark stage; - 02 - given off into the atmosphere for animals/other organisms to use for respiration.
(d) (i) Why green plants are absent at the lower depth of some lakes: Light intensity decreases with depth in water bodies; so at certain depths in water, there is no light for photosynthesis to occur.
(ii) Importance of decomposers to flowering plants: Decomposers (fungi/bacteria) break down dead organic matter; and release the nutrients in them; 002 in the soil/water/environment; which is absorbed by plants for growth.