Biology Paper 3 Marking Scheme
KCSE CLUSTER TESTS 23
Biology Paper 3
NOTE: - For the procedure, observation and conclusion to be correct, the food substance must be correct
. - A ward marks for procedure, observation and conclusion only.
- Formulae of 4 3,, CuSO NaHCOHCl should be correct if used.
- A ward for Benedict’s solution and heating once under reducing sugars and give equivalent if they are correct under no-reducing sugars.
NOTE: - Function is tied to the food nutrients. -
(b) is tied to (a)
15 marks
(a) X - Vein; Reason:
-Has thin/thinner/less muscular;
-Has wide/wider lumen; Y- Artery Reason:
-Has thick/thicker/more muscular wall;
-Has narrow /narrower lumen; (4marks) Any 1st one Reason is tied to the identity.
(b) X-Carries/transport deoxygenated blood from body tissues;
Y-Carries/transports oxygenated blood to body tissues; (2marks)
(c) Y-Thick muscular walls to withstand high pressure of blood; -
Narrow lumen which increases pressure of the blood for ultrafiltration; (2marks)
(d) X-Varicose veins; Y-Arteriosclerosis; rej wrong spellings
15 marks
(a) (i) Fruit; (1mark) Rej plural fruits but acc correct reason
(ii) Has/presence of two scars/points of attachment of receptacle and of style; (1mark)
(iii) Has pericarp/fruit wall; Any 1st one.
Note: Drawing marks
D1 Continuous outline.
D2 Endocarp drawn with seeds/locoli and juice sacs shown.
D3Central placenta enclosed in a ring.
Rej: if epicarp is single line
(b) cm
(iii) Axial/Axile/central; (1mark)
(c) (i) Animal dispersal; acc animals
(ii) -Brightly coloured to attract animals/agents of dispersal;
-Scented to attract animals;
-Seeds have hard/slimy/slippery coat to prevent digestion;
-Succulent/juicy to attract animals; (ii) tied to (i)
10 marks