Biology Paper 3 Marking Scheme
KCSE CLUSTER TEST 14
Biology Paper 3
b) (i) Cubes turn blue-black/blue in colour ;(1mk)
(ii) Starch present.(1mk)
(iii) L1 –Blue black colour spread throughout the cube; OWTTE.(1mk)
L3 – Blue black colour only on the sides (periphery) of the cube ;(1mk)OWTTE.
(iv) ―Cube L1 has a larger surface area to volume ratio and the rate of diffusion of iodine molecules is faster; (1mk).
―Cube L3 has a smaller surface area to volume ratio and the rate of diffusion of the iodine molecules is slower; (1mk)
c) (i) A permanent translucent spot that allows light to pass through is formed.(1mk)
(ii) Oils/lipids present; Rej fats present.(1mk)
(iii) To dry it.(1mk)
d) (i) A white emulsion/suspension is formed;(1mk)
(ii) Liquid R is broken down into tiny droplets/Emulsification of liquid R.(1mk)
(iii) It increases surface area for digestion (by lipase enzyme);
(iv) Bile ;(1mk)
13 marks
(a) (i) S1 Clavicle .(1mk)
S2 Scapula.(1mk)
D3 Humerus.(1mk) Rej wrong spellings
(ii) ―Presence of glenoid cavity for articulation with the head of humerus;
―Broad and flattened for (shoulder) muscles attachment;
―Has spine for muscle attachment;
―Has acromion/metacromion/coracoids processes for muscle attachment;
―Has acromion process for articulation with the clavicle; Acc first correct one.
(iii) ―Surface for attachment of muscle/tendons/ligaments;
―Prevents overstretching of the lower arm/limits movement at the joint (act as a stopper); Mark first one.
(iv) 1―Ball and socket joint allows movements in all planes/direction/through 0 360 .
―Round head of a bone fitting into a cavity/depression of another.
2―Hinge joint allows movement in one plane/direction/through 0 180 .
―Depressions in one bone allows the smooth condyles of another to fit and articulate.
(v) Fore arm/lower arm ;(1mk) Rej arm alone.
(vi) cm 4.8 (1mk)
(viii) 1 4.8 4.8 X cm cm ionmagnificat   ;Rej without sign. (1mk)
(b) (i) Duodenum ;(1mk)
(ii) H ―Sodium hydrogen carbonate;
―Sodium glycocholate;
―Sodium taurocholate; Acc one (1mk)
J ―Hydrochloric acid;
―Pepsin;
―Rennin;Rej Renin .Acc one.
(iii) Storage of faeces ;(1mk)
(iv) It secretes (digestive) enzymes and hormones ;(1mk)
19 marks