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This is recycling of nitrogen compounds in nature; Tree nitrogen in the air cannot be used by plants; but has to be
converted into ammonium compounds; and nitratesin order to be reabsorbed; It is done in the following ways.
- The atmospheric nitrogen and oxygen combine to form nitric and nitrous acids; The acids combine with minerals in the soil;
to form nitrates that are absorbed; Fixation of nitrogen is done by nitrogen fixing bacteria; called Rhizobium; This bacteria
lives in root nodules; of leguminous plants; These bacteria absorb the nitrogen and convert it into nitrates; which are used by
the plants; other free living bacteria in the soil; like Azotobacter absorb nitrogen and then it is absorbed by the soil; Nitrifying
bacteria; like nitrosomonas; and nitrocucous are also nitrifying bacteria; when plants and animals did; they decompose;
releasing the ammonium compounds which are converted by nitrifying bacteria into nitrates and then nitrites; which are then
absorbed by the plants; which are then absorbed by the plants; However there are some bacteria that, convert
nitrates into nitrogen gas; which escapes back into the atmosphere; These are known as denitrifying bacteria; examples are
pseudomonas and dentrificans; They reduce the nitrates to obtain oxygen gas. (Accept the diagram to cycle for
nitrogen whose arrows are properly pointed
gregorymasila answered the question on February 23, 2018 at 12:09
- (a) Describe the photosynthetic theory of opening and closing of the stomata.
(b) Describe the regulation of blood sugar level in man.(Solved)
(a) Describe the photosynthetic theory of opening and closing of the stomata.
(b) Describe the regulation of blood sugar level in man.
Date posted: February 23, 2018. Answers (1)
- The pancreas and the liver work together in the regulation of glucose in the blood.
i) State the role of these organs when the concentration...(Solved)
The pancreas and the liver work together in the regulation of glucose in the blood.
i) State the role of these organs when the concentration of glucose in blood is below normal.
ii) What would be the effect of removing the pancreas from the body?
iii) Distinguish between diabetes mellitus and diabetes insipidus
Date posted: February 23, 2018. Answers (1)
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b) Describe the mechanism of regulation of the amount of light entering the eye.(Solved)
a) Describe the process of accommodation in the human eye.
b) Describe the mechanism of regulation of the amount of light entering the eye.
Date posted: February 23, 2018. Answers (1)
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Describe the uptake and movement of water from the soil to the leaves of a tall plant till transpiration
Date posted: February 23, 2018. Answers (1)
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(i) Golgi apparatus
(ii) Mitochondria
Date posted: February 19, 2018. Answers (1)
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Name the organelle that:-
a) Manufacture and transport lipids and steroids in a cell.
b) Contain enzymes that are capable of destroying old damaged cells.
c) Control all the processes in a cell.
d) Form cilia and flagella in cells that have them.
Date posted: February 19, 2018. Answers (1)
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State two differences between bryophytes and pteridophytes
Date posted: February 19, 2018. Answers (1)
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Date posted: February 19, 2018. Answers (1)
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State three causes of variation in living things.
Date posted: February 19, 2018. Answers (1)
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State the significance of sunken stomata in plants.
Date posted: February 19, 2018. Answers (1)
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Highlight three importance of transpiration in plants
Date posted: February 19, 2018. Answers (1)
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State three differences between male and female gametes
Date posted: February 19, 2018. Answers (1)
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(a) Name two divisions in the kingdom Plantae that show alternation of generation
(b)Name the phylum whose member possesses a notochord.
Date posted: February 19, 2018. Answers (1)
- (a) What is homeostasis? (b) Name three processes in the human body in which homeostasis is involved (Solved)
(a) What is homeostasis? (b) Name three processes in the human body in which homeostasis is involved.
Date posted: February 19, 2018. Answers (1)
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A patient was given a drug which caused afferent arteriole entering the glomerulus to dilate while efferent arteriole constricted. Explain the effect the drug had to the amount of urine produced.
Date posted: February 19, 2018. Answers (1)
- Name the part of the brain responsible for:-
i) Maintaining balance of the body.
ii) Thermoregulation and osmoregulation.
iii) Sensation of pain, touch and sight
(Solved)
Name the part of the brain responsible for:-
i) Maintaining balance of the body.
ii) Thermoregulation and osmoregulation.
iii) Sensation of pain, touch and sight
Date posted: February 19, 2018. Answers (1)
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Distinguish between analogous and homologous structures
Date posted: February 19, 2018. Answers (1)
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How is the rate of diffusion affected by:
(i) Temperature
(ii) Concentration…
(iii) Surface area to volume ratio
Date posted: February 19, 2018. Answers (1)
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Distinguish between hypertonic and hypotonic solutions.
Date posted: February 19, 2018. Answers (1)
- Highlight the importance of the respiratory surface being:
1. Thin ...(Solved)
a) Highlight the importance of the respiratory surface being:
1. Thin
2. Moist
(b) State three adaptations of gills to their function.
(c) State how a guard cell is adapted to its function.
Date posted: February 19, 2018. Answers (1)