KNEC KCSE BIOLOGY TOPICAL QUESTIONS

K.C.S.E Biology Q & A - MODEL 2019PP1QN25

2/7/2020

K.C.S.E Biology Q & A - MODEL 2019PP1QN25

State one characteristic of muscles responsible for each of the following:
(a) peristaltic movement
(b) movement of limbs

answers

(a) spindle shape
Lack striations/ not striated
Uninucleated /one nucleus

(b) striated;
Numerous mitochondrion;
Multinucleated/many nucleus
Cylindrical shaped.

Comments

Explain the evolutionary basis for the ever changing drugs for malaria treatment.

2/7/2020

Comments

K.C.S.E Biology Q & A - MODEL 2019PP1QN24

Explain the evolutionary basis for the ever changing drugs for malaria treatment.

answers

malaria causing parasite over time become resistant to some malaria drugs; due to (gradually changing their genetic constitutions) mutation; which with time result in the evolution and eventual, perpetuation of the new strains of parasite hence necessitating the discovery of a more effective drug to counter the new/ emerging strains;

Comments

Plasmodium vivax and Plasmodiuin ovale are transmitted by a mosquito. State with a reason whether the two organisms can interbreed.

2/7/2020

Comments

K.C.S.E Biology Q & A - MODEL 2019PP1QN24

Plasmodium vivax and Plasmodiuin ovale are transmitted by a mosquito. State with a reason whether the two organisms can interbreed.

answers

(a) they can interbreed; because they belong to the same genus;
They cannot interbreed; because they do not belong to the same species.

Comments

State three homeostatic roles of the liver.

2/7/2020

Comments

K.C.S.E Biology Q & A - MODEL 2019PP1QN23

State three homeostatic roles of the liver.

answers

Thermoregulation;
Blood sugar regulation
Protein/amino acid/fat regulation

Comments

K.C.S.E Biology Q & A - MODEL 2019PP1QN22

2/7/2020

Comments

K.C.S.E Biology Q & A - MODEL 2019PP1QN22

The chart below illustrates how respiratory gases are transported in the human blood.

(a) Identify gas Q.
(b) Explain the advantage oxyhaemoglobin has over carboxyhaemoglobin.

answers

(a) carbon(ii) oxide acc. CO
(b) Oxyhaemoglobin is unstable/fully dissociate, releasing oxygen to the tissues/dissociate giving haemoglobin free to take up more gaseous molecules(hence constantly supplying the much needed oxygen to the respiratory tissues); carboxyhaemoglobin is stable/binds itself on the haemoglobin molecules /does not dissociate ,hence starving the tissues/cells of the oxygen ,leading to suffocation/death

Comments

Make a diagram of a simple, bibbed leaf with a serrated margin.

2/7/2020

Comments

K.C.S.E Biology Q & A - MODEL 2019PP1QN21

Make a diagram of a simple, bibbed leaf with a serrated margin.

answers

Comments

K.C.S.E Biology Q & A - MODEL 2019PP1QN20

2/7/2020

Comments

K.C.S.E Biology Q & A - MODEL 2019PP1QN20

State how each of the following features enhance efficient movement of fish in water:
(a) Scale
(b) body shape

answers

(a) faces towards the back/overlap/points backwards to provide a smooth surface for easier movement in water/are stony/ covered with mucus for easier /smooth movement in water/ reduce friction making
(b) streamlined body shape to reduce friction / pointed(stuff) head for easier penetration / passage in water.;

Comments

K.C.S.E Biology Q & A - MODEL 2019PP1QN19

2/7/2020

Comments

K.C.S.E Biology Q & A - MODEL 2019PP1QN19

Below is a diagram of the human digestive system.

(a) Label with Y on the diagram where enzyme amylase is produced.
(b) Besides the digestive role, explain one other function of the part labelled H.

answers

(b) Endocrine function/secrets (insulin/ glucagon) hormones; responsible for blood sugar regulation;

Comments

Name the type of tooth in carnivores mainly used for piercing and killing of preys.

2/7/2020

Comments

K.C.S.E Biology Q & A - MODEL 2019PP1QN18

Name the type of tooth in carnivores mainly used for piercing and killing of preys.

answers

canine acc. canines

Comments

K.C.S.E Biology Q & A - MODEL 2019PP1QN17

2/7/2020

Comments

K.C.S.E Biology Q & A - MODEL 2019PP1QN17

Below are photographs of two dogs.

Explain the possible reason for the difference in the length of their fur.

answers

Geographical distribution; made the animals adapt to survive in their environments(cold/hot), with those having thick fur being adapted to cold regions (for insulation); acc. Converse animal with short fur to adopt to hot area.
Genetic/being passed from parents to offspring's/genetic inheritance / genes being passed from parents to offspring;

Comments

State two benefits of mutation in living organisms.

2/7/2020

Comments

K.C.S.E Biology Q & A - MODEL 2019PP1QN16

State two benefits of mutation in living organisms.

answers

Can bring about beneficial/advantageous traits/polyploidy in plants/resistance to diseases/ high yields/early maturity/resistance to malaria in sickle celled traits in animals;
Increases heterozygosity (and size of gene pool) increase variation;

Comments

State the significance of transpiration to a plant.

2/7/2020

Comments

K.C.S.E Biology Q & A - MODEL 2019PP1QN15

State the significance of transpiration to a plant.

answers

(b) enable the plant to get rid of excess water
Creates a suction force /help in the uptake of water /mineral/salts from the soil
Maintains turgor in plants/turgidity in cells
Cools the plant

Comments

Distinguish between guttation and transpiration.

2/7/2020

Comments

K.C.S.E Biology Q & A - MODEL 2019PP1QN15

Distinguish between guttation and transpiration.

answers

Comments

Name the evidence of organic evolution exhibited by occurrence of similar amino acid molecules in a range of organisms.

2/7/2020

Comments

K.C.S.E Biology Q & A - MODEL 2019PP1QN14

Name the evidence of organic evolution exhibited by occurrence of similar amino acid molecules in a range of organisms.

answers

(b) comparative physiology/ biochemistry/cell biology;
Acc. Serology /comparative serology.

Comments

Explain why fossil records as evidence of organic evolution are usually incomplete.

2/7/2020

Comments

K.C.S.E Biology Q & A - MODEL 2019PP1QN14

Explain why fossil records as evidence of organic evolution are usually incomplete.

answers

(a) partial/ entire decomposition of dead organisms/ organic matter;
Some parts of or entire dead organisms are eaten by scavengers;
Soft bodied organisms do not fertilize;
Destruction of parts due to natural disasters, like earthquakes/earth movements like, faulting /folding/ volcanicity/ mass movement;
Distortion of parts of an organism due to sedimentary/ faulting/folding/volcanic

Comments

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K.C.S.E Biology Q & A - MODEL 2019PP1QN25

K.C.S.E Biology Q & A - MODEL 2019PP1QN25

Explain the evolutionary basis for the ever changing drugs for malaria treatment.

Explain the evolutionary basis for the ever changing drugs for malaria treatment.

Plasmodium vivax and Plasmodiuin ovale are transmitted by a mosquito. State with a reason whether the two organisms can interbreed.

Plasmodium vivax and Plasmodiuin ovale are transmitted by a mosquito. State with a reason whether the two organisms can interbreed.

State three homeostatic roles of the liver.

State three homeostatic roles of the liver.

K.C.S.E Biology Q & A - MODEL 2019PP1QN22

K.C.S.E Biology Q & A - MODEL 2019PP1QN22

Make a diagram of a simple, bibbed leaf with a serrated margin.

Make a diagram of a simple, bibbed leaf with a serrated margin.

K.C.S.E Biology Q & A - MODEL 2019PP1QN20

K.C.S.E Biology Q & A - MODEL 2019PP1QN20

K.C.S.E Biology Q & A - MODEL 2019PP1QN19

K.C.S.E Biology Q & A - MODEL 2019PP1QN19

Name the type of tooth in carnivores mainly used for piercing and killing of preys.

Name the type of tooth in carnivores mainly used for piercing and killing of preys.

K.C.S.E Biology Q & A - MODEL 2019PP1QN17

K.C.S.E Biology Q & A - MODEL 2019PP1QN17

State two benefits of mutation in living organisms.

State two benefits of mutation in living organisms.

State the significance of transpiration to a plant.

State the significance of transpiration to a plant.

Distinguish between guttation and transpiration.

Distinguish between guttation and transpiration.

Name the evidence of organic evolution exhibited by occurrence of similar amino acid molecules in a range of organisms.

Name the evidence of organic evolution exhibited by occurrence of similar amino acid molecules in a range of organisms.

Explain why fossil records as evidence of organic evolution are usually incomplete.

Explain why fossil records as evidence of organic evolution are usually incomplete.

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