Mastering KCSE Biology with Comprehensive Topical Questions and Answers
K.C.S.E Biology Q & A - MODEL 2003PP1QN12b
Name two sex – linked traits in humans.
answers
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K.C.S.E Biology Q & A - MODEL 2003PP1QN12
What is meant by the term sex – linkage?
answers
K.C.S.E Biology Q & A - MODEL 2003PP1QN06.
Distinguish between analogous and homologous structures.
answers
​Analogous structures – structures which (appear similar and ) perform similar functions but have different origins.
Homologous structures – structures which have a common origin but (have evolved to ) perform different functions. K.C.S.E Biology Q & A - MODEL 2003PP1QN05
A bone obtained from a mammal is represented by the diagram below.
​a) Name the bone.
b) Which bones articulate with the bone shown in the diagram at the notch?
answers
a) Ulna
b) radius; Humerus;
K.C.S.E Biology Q & A - MODEL 2002PP1QN20b
Describe how the cervical, lumbar and sacral vertebrae are suited to their functions.
answers
​ Cervical vertabrae
K.C.S.E Biology Q & A - MODEL 2002PP1QN20
Name three types of skeletons found in multicellular animals
answers
K.C.S.E Biology Q & A - MODEL 2002PP1QN14
Distinguish between divergent and convergent evolution giving example in each case.
answers
​Divergent basic structural form is modified to serve different functions; e.g. vertebrate forelimbs, break structure in birds/ feet in birds’ convergent different structures are modified to pass or similar functions e.g. wings and birds and insects/ eye of human and octopus, vertebrates for humans e.g. squeal, legs of vertebrae and insects .
K.C.S.E Biology Q & A - MODEL 2002PP1QN14
State two ways in which Home sapiens differs from Homo habilis
answers
K.C.S.E Biology Q & A - MODEL 2002PP1QN14
What is organic evolution
answers
K.C.S.E Biology Q & A - MODEL 2002PP1QN11
Give an example of a sex – linked trait in humans on:
Y CHROMOSOME. X CHROMOSOME.
answers
​Y CHROMOSOME
Tuft and hair sprouting from pinna / baldness; hairy pinna; X CHROMOSOME Colour blindness / haemophilia. K.C.S.E Biology Q & A - MODEL 2002PP1QN08
Which type of joint is found at the articulations of
a) Pelvic girdle and femur b) Humerus and ulna
answers
a) Ball and socket
b) Hinge
K.C.S.E Biology Q & A - MODEL 2001PP1QN17b
Describe how semicircular canals perform their functions
answers
​There are three semi – circular canals; arranged in planes at right angle to each other; at the end of each canal is swelling called ampulla’s which contains receptors.
The movement of the cause movement of the fluid in at least one canal, the fluid movement deflects / displaces the coperta and thus stimulating the receptors / sensory hairs, the impulse / nerve sensory impulse is transmitted / conducted to the brain; by auditory nerve, about the movement of the body / head. K.C.S.E Biology Q & A - MODEL 2001PP1QN17a
State the functions of the following parts of the mammalian ear;
(i) Tympanic membrane (ii) Eustachian tube (iii) Ear ossicles
answers
​ a) i) Tympanic membrane.
Receives sound waves (from the air); and vibrates / transforms sound wave into vibrations to transmit them to the ear osssicles / malleus; acc. Hammer for malleus. ii) Eustachain tube. Equalizes the air pressure in the middle ear to that in the outer ear. iii) Ear ossicles Amplify / transmits vibrations from the tymphanic membrane in the inner ear / venestra ovalis / oval window. K.C.S.E Biology Q & A - MODEL 2001PP1QN14
Tallness in pea plants is due to a dominant gene Two tall pea plants were crossed and their F1 generation were in the ratio of 3 tall: 1 short. Using letter T to represents the gene for tallness and t for shortness give the
(a) (i) genotype of the parents (ii) Gamete of the parents (iii) Genotype ratio of the F1 generation (b) What is meant by the term testcross in genetic studies?
answers
​(a) (i) Tt, Tt
(ii) Tt and Tt (iii) 1TT; 2Tt; 1tt/ 1 tall homozygous; 2 tall heterozygous 1 short homozygous 1:2:1 (b) Crossing a homozygous recessive organism with an organism which shows dominant characteristics. K.C.S.E Biology Q & A - MODEL 2000PP1QN12
The chart below represents the result of successive crosses, staring with redflowered plants and white flowed plants and in which both plants are pure breeding.
(a) What were parental genotype? Use letter R to represent the gene for red colour and r for white colour
(b) (i) What was the colour of the flowers in the first filial generation? (ii) Give a reason for your answer in b (i) above (c) If 480 red flowered plants were obtained in the second filial generation, how many F2 plants and white flowers? Show your working.
answers
(a) RR and rr
(b) (i) red (ii) complete dominant; i.e Rd dominant/ white recessive (c) Ratio of filial generation: 3: 1 (I.e. in every 4 flowers 3 are red 1 is white Therefore 480 red flowers means ¾ of the total number Total number of flowers (480 x 4)/3 = 640 So ¼ of 640 flowers are white in F2 plants ¼ x 640 = 160 flowers K.C.S.E Biology Q & A - MODEL 2000PP1QN07
Give reason why each of the following is important in the study of evolution:
a) Fossils records b) Comparative anatomy.
answers
(a) Fossils records
Gives evidence of types of plants/ animals/ organism that exist at a certain geological age. Long ago Gives evidence of morphological/ anatomical. Structure/ changes that have occurred over a long period of time. (b) Comparative anatomy. Gives evidence of relationship among organisms Gives evidence of common ancestry of a group of organisms; e.g. structural/ functional relationship among organization
​K.C.S.E Biology Q & A - MODEL 2000PP1QN06
Give a reason why lumbar vertebrae have long and broad transverse process
answers
K.C.S.E Biology Q & A - MODEL 2000PP1QN01
What is the function of the following cells in the retina of human eye ? Cones
answers
(a) Cones Discrimination of colours/ details/ accurate/ vision colour perception/ sensitivity to high intensity/ bright
(b) Rods Dim light vision/ low light intensity K.C.S.E Biology Q & A - MODEL 1999PP1QN09
The diagram below shows surface view of a human brain.
a)Name the parts labeled B and C.
b) State three functions of the part labelled A c) State what would happen if the part labeled B was damaged.
answers
a) B- Cerebellum
C- Medulla Oblongata ; Acc Oblongata alone b) Control locomotion motor area/sends impulse to affectors/controls
K.C.S.E Biology Q & A - MODEL 1999PP1QN04
State two advantages of natural selection to organisms
answers
K.C.S.E Biology Q & A - MODEL 1998PP1QN19
Discuss the various evidences, which show that evolution has taken place.
answers
​Comparative anatomy/taxonomy.
K.C.S.E Biology Q & A - MODEL 1998PP1QN17
The diagram below represents a nerve cell.
(a) (i) Identify the nerve cell.
(ii) Give a reason your answer in (a) (i) above (b) Name the structure labeled T (c) Using an arrow indicate on the diagram the direction of movement of an impulse in the cell.
answers
(a) (i) Sensory neurone/sensory nerve cell; reject sensory nerve
(ii) Cell body on a branch/ at the side of axon/off the axon/cell body unipolar both axon and dendron are long. (b) T- myelin sheath; Acc Neurilema (c) Direction of impulse from receptor towards cell body. K.C.S.E Biology Q & A - MODEL 1998PP1QN12
In a family with four children, three were found to have normal skin pigmentation while one was an albino. Using letter A to represent gene for normal skin pigmentation and a to represent the gene for albinism,
(a) What are the genotypes of the parents? (b) Work out the genotype of (i) Normal pigmentation (ii) The albino child Genotype of normal pigmented children (c) What is the probability that the fifth child will be an albino?
K.C.S.E Biology Q & A - MODEL 1998PP1QN09
What makes young herbaceous plant remain upright?
ANSWERS
K.C.S.E Biology Q & A - MODEL 1998PP1QN07
The diagram below represents a mammalian bone
​(a) Name the bone
(b) Name the type of the joint formed by the bone at its anterior end with the adjacent bone
ANSWERS
(a) Femur
(b) Ball and socket |
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