Biology Paper 1 Marking Scheme
KCSE CLUSTER TESTS 16
Biology Paper 1
(a)
X- Guard cell:
W-Stoma:rej Stomata
(b)
‗Have chloplast that help in the process of photosynthesis:
‗Have thin outer wall and thick inner wall to enhance bulging during opening of stomata;
4 marks
Entamoeba histolytica;
Mycobaterium tuberculosis
2 marks
2 marks
(a) A-Concentration of salt was isotonic;to that of the cytoplasm of the Red blood cells hence no change;
(b) B-most cells haemolysed;due to hypotonic salt solution;
(c)
4 marks
(a) adenosine diphosphate/ATP
(b) ADP as 2 phosphate;ATP as 3 phosphate,ATP is energy rich while ADP is energy defiant;
(c) mitochondrion;rej mitochondria
4 marks
(a) I ntermittent growth curve;
(b) Moulting ;
(ii) ecdysone/moulting ormone;
(c) allows the passage of Male nuclei to react the egg cell;
4 marks
Availability of Oxygen;temperature;amount of respiratory substrate.
4 marks
They absorb lead vapour emitted by motor vehicle exhaust fumes;when eaten they cause lead poisoning;
2 marks
2 marks
deamination
Arginase
Detoxification
3 marks
a) Contnuous;
b) Nutrition/environment;genes;
3 marks
existence of a plant as a gamatephyte and sporophyte
Bryopyta pteridopyta.
1 marks
.high temperatures;high CO2 concentration
3 marks
.to neutralize excess hydrochloric acid;
Condensation
Sucrose
3 marks
difusion;guttation;
2 marks
Fusion of one male nuclei with a functional egg nuclei to form a diploid zygote while the other male nucleus fuse with two nuclei to form a triploid zygote. b)Marinal parietal;basal;free central exile;
3 marks
resistant to diseases/pests; high yielding; long production period;
2 marks
a)seminal vesicles;cowpers;prostate gand
b)
(i)many/numerous mitochondria;
(ii) long tail
4 marks
(a) Sebaceous glands ;
(b)
‗Antiseptic;
‗Gives hairs water repelling property;
‗Keeps the skin supple;
‗Prevents the from drying ;
3 marks
Presence of antibodies; and white blood cells in blood that kill/destroy pathogens ;
b) Higher concentration of oxygen in pulmonary vein/higher concentration of carbon (IV) oxide in pulmonary artery ;
3 marks
(i) stimulate growth of graffian follicles;
(ii) maturation of sperms
2 marks
(a) Glycogen
(b) POLYSACHARIDE MONOSACCARIDE
‗Not sweet. ‗Sweet
‗Insoluble in water. ‗Soluble in water
‗Many monomers ‗One monomer
3 marks
(a)Phenomenon where organisms with beneficial mutations/variations/favourable xties/good adaptations in a population survive; obtain resources and reproduce and pass genes to offsprings while those with unfavourable or unsuitable variations/mutations/x-tics do not survive but die and do not pass their genes/mutations to offspring;
(b)
‗Industrial melanism is peppered moth;
‗Resistance of some bacteria to antibiotics;
‗Resistance of malaria parasite to ant-malaria drugs;
‗Resistance of pest to pesticides and insects to insecticides;
4 marks
vascularization; thin epithelia; presence of trophoblatic villi;close proximity of teatol and maternal circulation;
2 marks
Have large air spaces for buoyancy;
Have thin walls for faster diffusion of respiratory gas
2 marks
Control amount of light entering the condenser;
Magnify the specimen;
2 marks
collects moisture/vapour; reducing saturation deficit;
Conceal stomata and reduce leaf exposed for transpiration;
3 marks
(a) it’s actively reabsorbed back to blood system; within the proximal convoluted tubule ;
(b) ‗Anti-diuretic hormone/ADH;
‗Aldosterone ;
4 marks