K.C.S.E Biology Q & A - MODEL 1997PP1QN20b
Describe how the mammalian small intestine is adapted to its function
answers
K.C.S.E Biology Q & A - MODEL 1997PP1QN20.
What is meant by the term digestion?
answers
K.C.S.E Biology Q & A - MODEL 1997PP1QN19
Describe how the tapeworm is adapted to a parasitic mode of life
answers
Has hooks/suckers: for attachment to wall of intestines: long; to increase surface area for absorption of food: award increase in S.A for absorption once. Secretes enzymes/to neutralize digestive enzymes; (mucus inhibitor substance/anti enzymes) Hermaphroditic: to ensure reproductive/ self fertilization. Production of many eggs: to ensure survival
Segment for egg dispersal: More than one host; for transmission: e.g T solium – pig (Intermediate host) T. Saginata. Long to fit in the intestine/ increase surface area for ( flatten) Absorption of food; Anaerobic survive in the gut with low Oxygen
K.C.S.E Biology Q & A - MODEL 1997PP1QN19
What is parasitism?
answers
K.C.S.E Biology Q & A - MODEL 1997PP1QN18
An experiment was carried out to determine the growth rates of bamboo and a variety of maize plants in two adjacent plots. The average height and average dry weight of plants from the two populations were determined over a period of twenty weeks. The data is as shown in the table below.
(a) Between which two weeks did the greatest increase in weight occur in
(b) Bamboo plants (ii) Maize plants (b) (i) Which of the two types of plants had a higher productivity by the end of the experiment (ii) Give a reason for your answer in (b) (i) above (c) Between weeks 14 and 18, the average height of the maize plants remained constant while average dry weight increased. Explain this observation (d) Suggest how the change in the average dry weight bamboo and maize Plants would have been at week 22 if the experiment was continued. (e) Why was it appropriate for this experiment to use (i) Dry weight instead of fresh weight (ii) Weight and height (f) Describe how the average height and weight of the plants were determined in this experiment. Average height Average dry Weight (g) Give a reason why secondary thickening does not occur in bamboo and maize plants
answers
(a) (i) Bamboo plants
4 and 6 (ii)Maize plants 12 and 14 (b) (i) Bamboo (ii) It had accumulated more weight and therefore greater dry weight (c) Maize plants have reached maturity/maximum height food being manufactured (in green parts); is utilized for growth storage primary in the cob. (d)Increase in weight – bamboo reject both increase/ decrease accept bamboo and maize increase/ decrease. (e) (i) Dry weight instead of fresh weight Fresh weight is dependant on the amount of water present in the plants and this fluctuates depending on environmental factors. (ii) Weight and height Both given a better measure of growth (f) Average height At every 2 weeks measure the height of samples of plants in each plot: Divide the total height by the number of plants in each of plot. Average dry weight Harvest the sample measure of the plants in each plot; dry to constant weight: And divide by the number of plants (g) Being monocots/ lack (Inter) fascicular cambium: K.C.S.E Biology Q & A - MODEL 1997PP1QN17
​Figures 1 and 2 below represent reproductive organ of plants and an animal respectively.
​(a) Which letters in figures 1 and 2 represents the organs that produce female gametes?
Figure 1 Figure 2 (b) What is the function of the structure labeled S? (c) Name the structure labeled W (d) Which letters in figures 1 and 2 represents the structures where fertilization takes place (e) Which letter in figure 1 represents the structure where male gametes are produced?
answers
​(a) Figure 1 R:
Figure 2 T: (b) Development of the foetous/zygote/fertilized/ova/egg/embryo (c) Style (d) R;P; (e) X K.C.S.E Biology Q & A - MODEL 1997PP1QN16
In a breeding experiment, plants with red flowers were crossed. The produced 123 plants with red flowers and 41 with white flowers
(a) Identify the recessive character Give a reason (b) What was the genotype of the parent plants that gave rise to the plants with a red and white flowers?
answers
​(a) White
Give a reason – Fewer numbers/ lower ratio; lower in numbers/ absence of white in parents & absence in offspring. (b) Heterozygous (c) Double recessive / homozygous (recessive)
K.C.S.E Biology Q & A - MODEL 1997PP1QN15
The equation below represent a metabolic that occurs in the mammalian live Amino acids →Organic compounds + urea
​(a) Name the process.
(b) What is the importance of the process to the mammal? (c) What is the source of amino acids in this process (d) What is the difference between essential and nonessential amino acids?
ANSWERS
​(a) Deamination
(b) Removal of excess amino acids availing energy in the body formation glycogen/ fat for storage. (c) Proteins (d) Essentials amino acids are acquired from food Non- essential are synthesized in the body K.C.S.E Biology Q & A - MODEL 1997PP1QN14
The diagram below represents a simplified nitrogen cycle.
​(a) Name the organisms that cause process E and J
(b) Name the process represented by F and H. (c) Name the group of organism represented by G
ANSWERS
(a) E- Denitrifying bacteria; e.g pseudomonas denitrifications
J- Nitrifying bacteria; Nitrobacteria reject nitrosamines (b) H- Death decay/ decomposition; excretion/ Aminonification putrefaction egestion. F- Nitrogen fixation (c) Plants K.C.S.E Biology Q & A - MODEL 1997PP1QN13
An experiment was carried out to determine the rate of transpiration in three plants A, B and C. Plants, A and B belonged to different species while plants B and C belonged to the same species. Plant C had all its leaves removed. The three plants were of similar size and were exposed to the same environment conditions. The results are as shown below in the graphs below
​(a) Suggest possible environment conditions under which the experiment was carried out between 30 and 60 minutes
(b) Account for the results obtained for plant C (c) Suggest the habitat for plant A and B. Give reasons for your answer. Habitat for plant A Habitat for plant B
ANSWERS
​(a)strong air/ winds
High temperature Low humidity; accept dry conditions/ sunlight (b)Absence of leaves/ stomata absent Transpiration; / little transpiration (c)Arid/dry/ desert/ accept semi- desert Reason Low rate of water loss; accept more/ a lot of water loss Wet/Moist/aquatic Reason High rate of water/ high rate of transpiration /acc. A lot of water loss K.C.S.E Biology Q & A - MODEL 1997PP1QN12
A person was able to read a book clearly at arm’s length but at normal reading distance.
(a) State the detect the person suffered from? (b) Why was he unable to read book clearly at normal distance (c) How can the defect be corrected?
ANSWERS
(a) Long sightedness/ hypermetropia
(b) Eye ball too short/ eye lens are unable to focus because they are flat/weak, unable to focus the image on the retina; eyes are unable to accommodate/ change their focal length (c)By wearing convex / biconvex lenses; accept converging lenses K.C.S.E Biology Q & A - MODEL 1997PP1QN11
​The following below represents a feeding relationship in an ecosystem
​(a) Write down the food chains in which the guinea fowls are secondary consumers
(b) What would be the short term effects on the ecosystem if lions invaded the area? (c) Name the organism through which energy from the sun enters the food web.
ANSWERS
​(a) Grass→ Grasshoppers → Guinea fowls
Grass→ Termites → Guinea fowls (b) Lions would compete with leopards Gazelle numbers would reduce Grass would increase (c) Grass; K.C.S.E Biology Q & A - MODEL 1997PP1QN10
Name a disease caused by lack of each of the following in human diet.
ANSWERS
K.C.S.E Biology Q & A - MODEL 1997PP1QN09.
State three pieces of evidence that support the theory of evolution
ANSWERS
K.C.S.E Biology Q & A - MODEL 1997PP1QN08
A person was found to pass out large volumes of dilute urine frequently.
Name the (a) Disease the person was suffering from (b) Hormone that was deficient
ANSWERS
​(a) Disease the person was suffering from
Diabetes inspidus ref. Diuresis/ water diabetes (b) Hormone that was deficient Antidiuretic hormone/ ADH/Vasopressin |
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