Mastering KCSE Biology with Comprehensive Topical Questions and Answers
K.C.S.E Biology Q & A - MODEL 2016PP1QN23
Name one salivary gland in humans.
answers
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Explain why it is not advisable to be in a poorly ventilated room with a burning charcoal stove.30/6/2020
K.C.S.E Biology Q & A - MODEL 2016PP1QN019
Explain why it is not advisable to be in a poorly ventilated room with a burning charcoal stove.
answer
​Charcoal in limited supply of air produces carbon(ii) oxide, which combines with haemoglobin forming Carboxylhaemoglobin which is a stable compound and does not dissociate easily, reducing capacity of the haemoglobin to carry oxygen leading to suffocation hence death
K.C.S.E Biology Q & A - MODEL 2016PP1QN016
State one use of each of the following excretory products of plants:
(a) colchicine (b) papain
answers
​(a) colchicine
Inducing polyploidy/ treatment (b) papain Meat tenderizer
K.C.S.E Biology Q & A - MODEL 2016PP1QN14
Give three factors that determine the amount of energy a human being requires in a day.
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K.C.S.E Biology Q & A - MODEL 2016PP1QN09
What is the effect of contraction of the diaphragm muscles during breathing in mammals?
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K.C.S.E Biology Q & A - MODEL 2016PP1QN09
Name two structures for gaseous exchange in aquatic plants.
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K.C.S.E Biology Q & A - MODEL 2016PP1QN05
State the economic importance of anaerobic respiration in plants.
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K.C.S.E Biology Q & A - MODEL 2016PP1QN04
State three functions of blood other than transport.
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K.C.S.E Biology Q & A - MODEL 2016PP1QN04
Name one defect of the circulatory system in humans.
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K.C.S.E Biology Q & A - MODEL 2016PP1QN02
Why are plants able to accumulate most of their waste products for long?
answers
K.C.S.E Biology Q & A - MODEL 2016PP1QN01
State two ways in which the muscles of the mammalian heart are special.
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K.C.S.E Biology Q & A - MODEL 2015PP2QN08
How is a mammalian heart structurally adapted to its function?
ANSWERS
K.C.S.E Biology Q & A - MODEL 2015PP2QN01
The diagram below illustrates a blood capillary surrounding a structure for gaseous exchange in human beings.
​(a) Name the gaseous exchange structure.
(b) Identify the gases labelled Y and Z. Y Z (c) How does the gas labelled Y reach the inside of the blood capillary? (d) How does cigarette smoking lead to lung cancer?
ANSWERS
​.(a) Alveolus;
(b) Y - oxygen/O2; Z - Carbon (IV) Oxide/CO2; (c) Oxygen concentration is lower in the blood capillary than in the alveolus; oxygen diffuses; through the epithelium and endothelium of capillary wall, plasma into the red blood cells where it combines with haemoglobin. (d) Cigarettes/tobacco contains tar; tar contains carcinogenic substances; which trigger cancer
K.C.S.E Biology Q & A - MODEL 2015PP1QN11
Name two structures used for gaseous exchange in plants.
answers
K.C.S.E Biology Q & A - MODEL 2015PP1QN09
The diagram below shows an experimental set up to investigate a certain physiological process in plants.
​(a) State the aim of the experiment.
(b) State the role of the following in the experiment: (i) potassium hydroxide; (ii) aluminum foil. (c) Account for the expected colour change in tube F.
answers
​(a) To show that carbon (TV) oxide is produced during respiration in plants;
(b) (i) Absorb carbon (IV) oxide from the (incoming) air; (ii) Exclude light / to prevent photosynthesis; (c) No colour change in tube F / no observable colour change. Carbon (IV) oxide removed/absorbed from air by potassium hydroxide.
K.C.S.E Biology Q & A - MODEL 2015PP1QN07
How is a guard cell structurally adapted for gaseous exchange?
answers
K.C.S.E Biology Q & A - MODEL 2015PP1QN03
.An individual is of blood group B positive.
(a) Name the antigens in the individual’s blood. (b) Give the reason why the individual cannot receive blood from a blood group A donor.
answers
​(a) (Antigen) B; Rhesus (antigen)/Rhesus factor/Antigen D
(b) Has antibody a in the blood plasma of the recipient and will correspond with antigen A in the donor’s blood, hence there will be antigen antibody reaction/agglutination.
K.C.S.E Biology Q & A - MODEL 2014PP2QN08
Describe the role of the human skin in homeostasis.
answers
When body temperature is lowered below normal; arterioles in the skin constrict; blood is diverted to a shunt system; less blood flows to the skin/less heat is lost; when body temperature is raised above normal;arterioles in the skin dilate;more blood flows to the skin; more heat is lost by convection and radiation;when body temperature is lowered below normal:erector-pilli muscle s contract, hair stands erect; more air is trapped, air is a bad conductor;and insulates the body against heat loss; when body temperature is raised above normal: erectorpi11i muscles relax, hair lies on skin;less air is trapped, more heat is lost; when body temperature is lowered below normal: less fluids are absorbed by sweat glands;less sweating, less vaporisation of water;
when body temperature is raised above normal:sweat glands are more stimulated and more sweat is produced; water in sweat evaporates and takes up heat from the body;body is cooled/body temperature is lowered;
K.C.S.E Biology Q & A - MODEL 2014PP2QN08
How does excretion take place in plants?
answers
K.C.S.E Biology Q & A - MODEL 2014PP2QN02
The diagram below illustrates the role played by red blood cells in the transportation of carbon (1V) oxide.
​(a) Other than the carbon (IV) oxide transportation in the red blood cells, name the other form of carbon (1V) oxide transportation in humans.
(b) (i) Name substance F (ii) Name the enzyme marked C and state its role in the reaction. Enzyme Role (c) Explain why transportation of carbon (1V) oxide in red blood cells is advantageous. (d) Explain the role of calcium ions in blood clotting.
ANSWERS
​(a) Carbonic acid/carbaminohaemoglobin/hydrogen carbonate;
(b) (i) Water; (ii) Carbonic acid; Role: catalyses reaction between carbon IV oxide and water to form (weak) carbonic acid; (c) Prevents accumulation of acidity/maintains pH of blood since hydrogen ions combine with haemoglobin to form Haemoglobin acids; Faster; due to the catalytic effect of carbonic anhydrase; (d) Activates thromboplastin; thrombokinase to neutralize heparin/convert prothrombin to thrombin; K.C.S.E Biology Q & A - MODEL 2014PP1QN27
The diagram below shows the gaseous exchange system of a locust.
​(a) Name the structure labelled Q.
(b) State the function of the part labelled R. (c) How is the part labelled S structurally adapted to its function?
ANSWERS
​ (a) Spiracle;
(b) Keep the trachea open for air passage; (c) Lacks spiral bands of chitin /to make it thin; for diffusion of gases; Moist; to dissolve respiratory gases; K.C.S.E Biology Q & A - MODEL 2014PP1QN24
The table provided shows the transportation of substances in the human body.
​Name the substances represented by
M N P
ANSWERS
​M - lungs;
N - Urea, ammonia. ; P - Digested food. water; mineral ions; K.C.S.E Biology Q & A - MODEL 2014PP1QN23
Below is an illustration of a cross section of a plant root showing the transportation of substances in the plant.
​(a) Name the substances transported along the paths labelled K and L.
K L (b) Give a reason for your answer in L above.
ANSWERS
​(a) K - Photosynthetic products/manufactured foods example vitamins/alicose/proteins/sucrose/maltose/fructose/lipids/nitrates;
L - Water and mineral salts; (b) The substances are moved into the star shaped xylem;
K.C.S.E Biology Q & A - MODEL 2014PP1QN19
Why is a burning charcoal stove in a poorly ventilated room likely to cause death of the inhabitants?
ANSWERS
K.C.S.E Biology Q & A - MODEL 2014PP1QN12
The diagram below represents a model used to demonstrate breathing in mammals.
​(a) Name the mammalian structure represented by the parts labelled D and E.
(i) D . (ii) E (b) State the observation made when the string is pulled downwards. (c) Explain the observation in (b) above.
ANSWERS
​(a) (i) Rib-cage/chest cavity;
(ii) Diaphragm; (b) The balloons are inflated; (c) Pulling down the string increases the volume of D, hence decreasing the pressure inside: The low pressure causes external atmospheric air to rush in and inflate the balloons; |
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