KNEC KCSE BIOLOGY TOPICAL QUESTIONS AND ANSWERS

Below is a diagram of a poorly planned town showing some building and facilities

8/1/2023

Comments

Below is a diagram of a poorly planned town showing some building and facilities

a) Giving evidence from the diagram, state two likely sources of water pollution. (2mks)

Industrial effluents because the factory is close to the river.
Domestic effluents since some houses are next to the river and the marsh.

b) State three ways that the positioning of the refuse pit and sewage works pose danger to the residence of the town. (3mks)

Drinking water contamination since the water works is close to the sewage works;
Spread of diseases to residents nearby because many pathogens and diseases vectors are found in the sewage works and refuse pit near the houses;
Air pollution because the prevailing wind carries unpleasant smell over the town;

c) Residents living close to the marsh are likely to suffer from malaria. Explain. (1mk)

The swamp is the breeding site for mosquito larva hence adult mosquitos may spread malaria to residents living nearby.

d) Suggest two control measures to overcome water pollution in the area. (2mks)

Treating industrial and domestic effluents before releases it into the water.
Cooling the water from the factories to avoid raising water temperature in the river and swamp.
Carry out environmental impact assessment before establishing factories/industries;etc

Comments

The diagram below represents a maize seedling.

8/1/2023

Comments

The diagram below represents a maize seedling.

a) Name the structure labeled A and C (2mks)

A – Coleoptile
B – Remaining of seed / seed.

b) State the functions of parts labeled A, B and C. (3mks)

A - Protects the delicate plumule as it pushes through the soil during germination.
B – Contains stored food which is hydrolyzed and used by the germinating seed / seedling before the seedling starts to photosynthesize.
C
– Anchors the seedling.
- Absorbs water and mineral ions.

c) Name the type of germination exhibited by maize (1mk)

Hypogeal germination

d) Name two conditions necessary for seed germination other than water and oxygen. (1mk)

Optimum temperature / warmth.
Growth hormones.
Viability of seed
Enzymes

e) What is the role of oxygen in seed germination? (1mk)

It oxidizes the stored food in the seed to give energy for growth/synthesis of new materials;

Comments

BIOLOGY REVISION KITS FORM 3 TERM 1 PAPER 2 MODEL26092022001

26/9/2022

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BIOLOGY REVISION KITS FORM 3 TERM 1 PAPER 2 MODEL26092022001

biology_revision_kits_form_3_term_1_paper_2__model26092022001.pdf
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BIOLOGY REVISION KITS FORM 3 TERM 1 PAPER 3 MODEL26092022001

26/9/2022

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BIOLOGY REVISION KITS FORM 3 TERM 1 PAPER 3 MODEL26092022001

biology_revision_kits_form_3_term_1_paper_3__model26092022001.pdf
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BIOLOGY REVISION KITS FORM 3 TERM 1 PAPER 1 MODEL26092022001

26/9/2022

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BIOLOGY REVISION KITS FORM 3 TERM 1 PAPER 1 MODEL26092022001

biology_revision_kits_form_3_term_1_paper_1__model26092022001.pdf
File Size:	924 kb
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A group of students carried out a study of the population growth of flour weevils.

4/11/2021

Comments

A group of students carried out a study of the population growth of flour weevils. They put 16 grams of maize flour into two equal boxes K and L respective . They then introduced equal numbers of weevils into the boxes. The boxes were kept under similar environmental conditions. The weevils were counted at intervals and the results recorded in the table below.

(a) Using a suitable scale ,draw two graphs on the same axes from the results in the table.
Plot approximate number of weevils present on the Y – axis( Use graph paper provided) (8mks)

(b) What were the approximate number of weevils present in the two boxes on the 70th day. (2mks)
Number in K: ..
Number in L:......

K - 555
L - 1020

(c) (i) On what day was the population of weevils in K 580. (1mk)

86th Day

(ii) Between which days was the population difference greatest . (1mk)

100 - 120

(d) Account for the shape of graph L between day 5 and day 100. (4 mks)

Increase in population; because there is adequate food; the number of reproducing individuals is increasing; wastes products have not accumulated to toxic levels.

(e) State factors that would make the human species assume the graph curve above in K. (4mks)

Diseases
Lack of food
Death rate equal to birth rate.

Comments

The diagram below represents female reproductive system;

3/11/2021

Comments

The diagram below represents female reproductive system;

(a) Name the part labelled ;A ,B ,C and D. (4mks)

A:

ovary

B:

Oviduct/fallopian tube

C:

Uterus/uterine wall

D:

D - Cervix

(b) State two functions of structure A. (2mks)

Produce ova femme hormones/ Estrogen and progesterone.

(c) How is part C adapted to its functions? (1mk)

Highly vascularized tosupply nutrients to foetus/drain away excretory wastes.
Inner wall lined with Endometrium for implantation of fertilized egg/zygote.
Muscular for peristalisis to expel menses during menstruation/parturition
Great capacity to expand during gestation to accommodation developing foetus

(d) Of what significance is part E to reproduction? (1mk)

Copulation/Achieve orgasm in Human male followed by ejaculation birth canal

Comments

The diagram below represents a maize seedling.

3/11/2021

Comments

The diagram below represents a maize seedling.

(a) Name the parts labeled P and Q. (2mks)

P:

Coleoptile/plumule sheath;

Q:

Root

(b) State the function of the part labeled R. (1mk)

Storage of food/enzyme/to provide food to the seedling

(c) Give three adaptations of the structure labeled S to its functions. (3mrks)

Elongated to increase surface area for absorption of water ‘b and c’ tied to ‘a’
Has many mitochondria for active transport
Has thin wall/thin walled for paste absorption of water and mineral salts

(d) What is the role of air in germination of the above seedlings? (2mks)

Air contains oxygen for respiration/oxidation to produce energy.

Comments

The diagram below shows a specialized cell from a human being.

3/11/2021

Comments

The diagram below shows a specialized cell from a human being.

(a) Identify the cell. (1mk)

Sperm cell/spermatozoon;

(b) Name the parts labelled A,B, and C. (3mks)

A:

A crosome;

B:

Nucleus

C:

Mitochondria

(c) State the functions of the part labeled D. (1mk)

Propels the sperm forward

(d) A student observed cells under a microscope and counted six (6) cells a cross the diameter of view. The diameter of field of view was found to be 1.25mm. Calculate the length of one of the cells observed. ( Answer in micrometer). (3mks)

Comments

Identify the type of asexual reproduction exhibited by yeast cells

1/11/2021

Comments

a) Identify the type of asexual reproduction exhibited by yeast cells (1mk)

Budding;

b) List down the functions of the following parts; (3mks)

i) Testis

Production of the male reproductive cell/gamete/sperm;
Production of androgens/male hormones.

ii) Fallopian tube

Fertilization takes place here/where fertilization occurs;
Passage of the female gamete/fertilized ovum to the uterus.

iii) Urethra

Passage of urine/sperms/semen;

Comments

State three ways how HIV and AIDS is transmitted in human population

1/11/2021

Comments

State three ways how HIV and AIDS is transmitted in human population (3mks)

Having sexual (unprotected) intercourse with an infected person;
Blood transfusion with infected blood;
From infected mother to child during birth;
Use of unsterilized, infected surgical instruments;
Sharing cutting/piercing instruments with infected people

Comments

State the function of Juvenile hormone in insect metamorphosis

1/11/2021

Comments

a) State the function of Juvenile hormone in insect metamorphosis (1mk)

leads to the formation of larval utricle;

b) (i) Give a reason why most insects are serious crop pests at the larval stage (1mk)

Growth rate in rapid/fast/high and shed cuticle several times hence feed a lot to have (desired) energy;

(ii) What happens at growth phase in insects growth curve (1mk)

Cells elongate before the cuticle harden;
Some cell division take place;

Comments

Oat coleoptiles were used in the experiment set ups shown below. Study the set-ups and answer the following questions.

31/10/2021

Comments

Oat coleoptiles were used in the experiment set ups shown below. Study the set-ups and answer the following questions.

(a) What type of response was being investigated above? (1mk)

Tropism/tropic response;

(b) Which of the set up above would act as a control experiment? (1mk)

(c) Explain what happened in set up B after 24 hours (2mks)

The side brushed with IAA increased concentration of this hormone (IA; This lead to increased cell elongation/growth hence a growth harvature away from the brushed side;

Comments

What is meant by ecosystem, carrying capacity?

31/10/2021

Comments

(a) What is meant by the following terms; (2mks)

(i) Ecosystem

A natural unit composed of abiotic and biotic factors whose instruction lead to a self sustaining system;

(ii) Carrying capacity

The maximum population of a species that a particular habitat can support;

Total no. of organisms a particular habitat/area/ecosystem/region/environment can support without depleting the resources;
Total no. of population of a species in a given habitat/area/ecosystem/environment can support without depleting the resources.

(b) Give two ways on how hydrophytes are adapted to the process of gaseous exchange (2mks)

Floating hydrophytes have numerous and large stomata on the upper epidermis;
Have aerenchyma tissues in their stems/leaves/roots to store air and for gaseous exchange;
Those in swampy environments have pneumatophods breathing roots;

Comments

The graph below represents a population growth of a certain herbivore in grassland ecosystem over a period of time.

3/8/2020

Comments

Suggest three factors that could have caused the population change between C and D.

Comments

<<Previous

​Below is a diagram of a poorly planned town showing some building and facilities

​a) Giving evidence from the diagram, state two likely sources of water pollution. (2mks)

​b) State three ways that the positioning of the refuse pit and sewage works pose danger to the residence of the town. (3mks)

​c) Residents living close to the marsh are likely to suffer from malaria. Explain. (1mk)

​d) Suggest two control measures to overcome water pollution in the area. (2mks)

​The diagram below represents a maize seedling.

​a) Name the structure labeled A and C (2mks)

b) State the functions of parts labeled A, B and C. (3mks)

​c) Name the type of germination exhibited by maize (1mk)

​d) Name two conditions necessary for seed germination other than water and oxygen. (1mk)

​e) What is the role of oxygen in seed germination? (1mk)

​BIOLOGY REVISION KITS FORM 3 TERM 1 PAPER 2 MODEL26092022001

​BIOLOGY REVISION KITS FORM 3 TERM 1 PAPER 3 MODEL26092022001

​BIOLOGY REVISION KITS FORM 3 TERM 1 PAPER 1 MODEL26092022001

(a) Using a suitable scale ,draw two graphs on the same axes from the results in the table. Plot approximate number of weevils present on the Y – axis( Use graph paper provided) (8mks)

(b) What were the approximate number of weevils present in the two boxes on the 70th day. (2mks) Number in K: .. Number in L:......

​(c) (i) On what day was the population of weevils in K 580. (1mk)

​(ii) Between which days was the population difference greatest . (1mk)

​(d) Account for the shape of graph L between day 5 and day 100. (4 mks)

(e) State factors that would make the human species assume the graph curve above in K. (4mks)

​The diagram below represents female reproductive system;

(a) Name the part labelled ;A ,B ,C and D. (4mks)

​A:

B:

C:

D:

​(b) State two functions of structure A. (2mks)

(c) How is part C adapted to its functions? (1mk)

​(d) Of what significance is part E to reproduction? (1mk)

​The diagram below represents a maize seedling.

​(a) Name the parts labeled P and Q. (2mks)

​P:

​Q:

​(b) State the function of the part labeled R. (1mk)

​(c) Give three adaptations of the structure labeled S to its functions. (3mrks)

​(d) What is the role of air in germination of the above seedlings? (2mks)

​The diagram below shows a specialized cell from a human being.

​(a) Identify the cell. (1mk)

​(b) Name the parts labelled A,B, and C. (3mks)

A:

B:

C:

​(c) State the functions of the part labeled D. (1mk)

(d) A student observed cells under a microscope and counted six (6) cells a cross the diameter of view. The diameter of field of view was found to be 1.25mm. Calculate the length of one of the cells observed. ( Answer in micrometer). (3mks)

​a) Identify the type of asexual reproduction exhibited by yeast cells (1mk)

​b) List down the functions of the following parts; (3mks)

i) Testis

​ii) Fallopian tube

​iii) Urethra

State three ways how HIV and AIDS is transmitted in human population (3mks)

​a) State the function of Juvenile hormone in insect metamorphosis (1mk)

​b) (i) Give a reason why most insects are serious crop pests at the larval stage (1mk)

​(ii) What happens at growth phase in insects growth curve (1mk)

​(a) What type of response was being investigated above? (1mk)

(b) Which of the set up above would act as a control experiment? (1mk)

(c) Explain what happened in set up B after 24 hours (2mks)

​(a) What is meant by the following terms; (2mks)

​(i) Ecosystem

(ii) Carrying capacity

​(b) Give two ways on how hydrophytes are adapted to the process of gaseous exchange (2mks)

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Below is a diagram of a poorly planned town showing some building and facilities

a) Giving evidence from the diagram, state two likely sources of water pollution. (2mks)

b) State three ways that the positioning of the refuse pit and sewage works pose danger to the residence of the town. (3mks)

c) Residents living close to the marsh are likely to suffer from malaria. Explain. (1mk)

d) Suggest two control measures to overcome water pollution in the area. (2mks)

The diagram below represents a maize seedling.

a) Name the structure labeled A and C (2mks)

c) Name the type of germination exhibited by maize (1mk)

d) Name two conditions necessary for seed germination other than water and oxygen. (1mk)

e) What is the role of oxygen in seed germination? (1mk)

BIOLOGY REVISION KITS FORM 3 TERM 1 PAPER 2 MODEL26092022001

BIOLOGY REVISION KITS FORM 3 TERM 1 PAPER 3 MODEL26092022001

BIOLOGY REVISION KITS FORM 3 TERM 1 PAPER 1 MODEL26092022001

(a) Using a suitable scale ,draw two graphs on the same axes from the results in the table.
Plot approximate number of weevils present on the Y – axis( Use graph paper provided) (8mks)

(b) What were the approximate number of weevils present in the two boxes on the 70th day. (2mks)
Number in K: ..
Number in L:......

(c) (i) On what day was the population of weevils in K 580. (1mk)

(ii) Between which days was the population difference greatest . (1mk)

(d) Account for the shape of graph L between day 5 and day 100. (4 mks)

The diagram below represents female reproductive system;

A:

(b) State two functions of structure A. (2mks)

(d) Of what significance is part E to reproduction? (1mk)

The diagram below represents a maize seedling.

(a) Name the parts labeled P and Q. (2mks)

P:

Q:

(b) State the function of the part labeled R. (1mk)

(c) Give three adaptations of the structure labeled S to its functions. (3mrks)

(d) What is the role of air in germination of the above seedlings? (2mks)

The diagram below shows a specialized cell from a human being.

(a) Identify the cell. (1mk)

(b) Name the parts labelled A,B, and C. (3mks)

(c) State the functions of the part labeled D. (1mk)

a) Identify the type of asexual reproduction exhibited by yeast cells (1mk)

b) List down the functions of the following parts; (3mks)

ii) Fallopian tube

iii) Urethra

a) State the function of Juvenile hormone in insect metamorphosis (1mk)

b) (i) Give a reason why most insects are serious crop pests at the larval stage (1mk)

(ii) What happens at growth phase in insects growth curve (1mk)

(a) What type of response was being investigated above? (1mk)

(a) What is meant by the following terms; (2mks)

(i) Ecosystem

(b) Give two ways on how hydrophytes are adapted to the process of gaseous exchange (2mks)