KNEC KCSE BIOLOGY TOPICAL QUESTIONS AND ANSWERS

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

Discuss the adaptations of the reproductive system of a male mammal to its function

18/9/2021

Comments

Discuss the adaptations of the reproductive system of a male mammal to its function

Positioned abdominal cavity in scrotal sac to provide cooler temperature for sperm devolvement
Has seminiferous tubules;- highly coiled linings consist of actively dividing cells. Between them are interstitical cells which produce androgens
Seminiferous tubules unite to form epididymis, a coiled tube; provides surface for sperm storage
Seminal vesicles: provide alkaline fluid which nourishes spermatozoa; prostrate gland secretes alkaline to neutralize the vaginal fluids, it also activates enzymes
Cowper’s gland, secretes alkaline fluid that neutralize acidity along the urethra
Erectile intromittent organ-projects from the body; made of spongy tissue, muscle and blood vessel it erects by having spaces in its spongy tissue filled with blood enabling it to penetrate vagina during coitus, is male to sperms in the female reproductive tract

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

K.C.S.E Biology Q & A - MODEL 2019PP1QN13

2/7/2020

Comments

K.C.S.E Biology Q & A - MODEL 2019PP1QN13

A female human being was found to have an extra sex chromosome in her cells.

(a) Give the total number of chromosomes in the female individual’s cells.
(b) Explain the possible cause of this condition.
(c) State two physical characteristics observed in the female individual with such a condition.

answers

(a) 47
(b)Non-disjunction/failure of homologous chromosome to separate/segregate (in anaphase I) or failure of sister chromosome to separate/segregate (in anaphase II); resulting in an extra X sex chromosome, X chromosome in a cell having XXX instead of XX;
(c) infertile / ovary abnormalities;
Taller than average female;
Development delays;
(more pronounced) signs of obesity;
Flat feet
Abnormally curved fingers;
Widely spaced eyes;
Abnormally shaped breast bone;

Comments

Describe the role of hormones in the human menstrual cycle.

1/7/2020

Comments

K.C.S.E Biology Q & A - MODEL 2018PP2QN07

Describe the role of hormones in the human menstrual cycle.

answers

After/at the onset of menstruation, (the anterior lobe of) the pituitary gland; secretes follicle stimulating hormone (FSH); the FSH causes the Graafian follicle; to develop into the ovary; and stimulate the ovary tissues to secrete oestrogen hormone; Oestrogen brings about repair/healing of the endometrium/uterine wall; its concentration increases to a level which stimulates the (anterior) pituitary gland; to secrete lutenizing hormone (L.H.) and stops further secretion of FSH;
The L.H. stimulates the maturation of the Graafian follicle; LH also stimulates the Graafian follicle to release an ovum into the (funnel of the) fallopian tube/causes ovulation; it also stimulates the remains of the Graafian follicle to form a yellow body/corpus luteum (in the ovary;
The corpus luteum is stimulated by the L.H. to produce progesterone; Progesterone then stimulates the thickening of the endometrium/inner lining of the uterine wall; in readiness for implantation; as progesterone level increases, it inhibits (the pituitary gland) from secreting FSH; further increase in progesterone level inhibits the pituitary gland from secreting L.H. This causes the corpus Luteum to degenerate; this reduces the amount of progesterone; the sudden drop in secretion of progesterone causes the endometrium to slough off/menstruation occurs; and the cycle is repeated;

Comments

Describe the mode of reproduction in a named fungus.

1/7/2020

Comments

K.C.S.E Biology Q & A - MODEL 2018PP2QN07

Describe the mode of reproduction in a named fungus.

answers

Rhizopus/mucor/mould; reproduce asexually; by sporulation; spores develop from a single cell forming sporangium; which bursts on maturity releasing spores; which are dispersed by air currents/wind germinating; to form new generation/ form a mycelium (if it lands on a suitable medium); Or
Yeast/Saccharomyces/Schizosaccharomyces; reproduce asexually;by budding; parent cell forms an outgrowth/projection/bud; this is followed by division of the nucleus into two; one of the nuclei moves into the bud; which grows and develops into a new cell;

Comments

K.C.S.E Biology Q & A - MODEL 2018PP2QN02

1/7/2020

Comments

K.C.S.E Biology Q & A - MODEL 2018PP2QN02

Below is a graphical representation of students’ height in a classroom.

(a) Name the type of curve illustrated.
(b) (i) State the type of variation represented by the curve.
(ii) State two meiotic processes that lead to variation among organisms.
(iii) Explain the role of variation in organisms.
(c) Explain the need for genetic counselling in present day health facilities.

answers

a) Normal distribution curve;
b) i. Continuous (variation);
ii. Independent assortment;
Crossing over;
iii. Organisms/individuals with advantageous traits/variations are favoured/selected by nature; and survive to reproduce/pass on/propagate the advantageous/favourable traits to their off-spring;
Or
Variation ensures propagation of desirable/favourable traits; to the future generations/off-spring, ensuring improved/quality population;
c) Provides information/advice to individuals/families/communities about genetic disorders;
Helps identify/test/advice families/communities on possible risks of genetic disorders;
Provides supportive services/serves as patient advocates/refer individuals/families to relevant health professionals;

Comments

State the significance of diploidy.

1/7/2020

Comments

K.C.S.E Biology Q & A - MODEL 2017PP2QN04

State the significance of diploidy.

answers

Ensures that the chromosomes/genetic constitution of the offspring is the same as that of parents;
Ensures perpetuation of a given species’ desired/favourable traits/qualities/continuity of the species;

Comments

K.C.S.E Biology Q & A - MODEL 2017PP2QN04

1/7/2020

Comments

K.C.S.E Biology Q & A - MODEL 2017PP2QN04

(i) Define the term diploidy.
(ii) Name the type of cell division that gives rise to diploid cells.
(iii) Name the type of cells in which the process named in (b) (ii) above Occurs.

answers

i. State of being/having two sets of chromosomes and therefore two copies of genes (especially in somatic/body cells);
ii. Mitosis;
iii. Body cells/somatic cells;

Comments

Explain how the sex of a male child is determined in human beings.

1/7/2020

Comments

K.C.S.E Biology Q & A - MODEL 2017PP2QN04

Explain how the sex of a male child is determined in human beings.

answers

Male produces sperm cells with X or Y chromosomes; if (by chance), Y chromosome containing sperm from male fuses with X chromosome containing egg from female ovum, an XY zygote results, giving rise to a male child;

Comments

State two advantages of hybrid vigour

30/6/2020

Comments

K.C.S.E Biology Q & A - MODEL 2016PP1QN30

State two advantages of hybrid vigour

ANSWERS

Resistance to pests/disease/adverse weather conditions
Increase yield
Earlier maturity/early maturity

Comments

<<Previous

​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)

​Discuss the adaptations of the reproductive system of a male mammal to its function

State two benefits of mutation in living organisms.

K.C.S.E Biology Q & A - MODEL 2019PP1QN13

Describe the role of hormones in the human menstrual cycle.

Describe the mode of reproduction in a named fungus.

K.C.S.E Biology Q & A - MODEL 2018PP2QN02

State the significance of diploidy.

K.C.S.E Biology Q & A - MODEL 2017PP2QN04

Explain how the sex of a male child is determined in human beings.

State two advantages of hybrid vigour

TOPICS

Form 2

Form 3

Form 4

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Categories

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

Discuss the adaptations of the reproductive system of a male mammal to its function