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)
(d) Of what significance is part E to reproduction? (1mk)
Copulation/Achieve orgasm in Human male followed by ejaculation birth canal
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)
(d) What is the role of air in germination of the above seedlings? (2mks)
Air contains oxygen for respiration/oxidation to produce energy.
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)
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
ii) Fallopian tube
iii) Urethra
Passage of urine/sperms/semen;
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
K.C.S.E Biology Q & A - MODEL 2019PP1QN16
State two benefits of mutation in living organisms.
answers
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;
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;
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; 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;
K.C.S.E Biology Q & A - MODEL 2017PP2QN04
State the significance of diploidy.
answers
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;
K.C.S.E Biology Q & A - MODEL 2017PP2QN04
Explain how the sex of a male child is determined in human beings.
answers
K.C.S.E Biology Q & A - MODEL 2016PP1QN30
State two advantages of hybrid vigour
ANSWERS
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