NYANDO DISTRICT MOCK EXAMINATION – 2008Kenya Certificate of Secondary Education (K.C.S.E)

231/3BIOLOGYPAPER 3

MARKING SCHEME

1 a) (i) Spermatozoa ; 1 mk Rj sperms (ii)

Mg= x 1900

L

M = 1A= 1 Accuracy= size must be the sameNo shading at allPosition on it is in the photographOnly on spermatozoan

(iii) S; 1 mk Nucleus 1 mk

b) (i) Mitochondria 1 mk Provide energy for the movement of the cell; 1 mk

(ii) The cell would not move/ swim (as it is the part it swings / flaps side ways to allow it push forwards) 1 mk

c) (i) 5 cm, 1 mk(ii) Magnified size= 5 cmmg = x 6

real size =

= 0.833 cm 2 mks

d) (i) Dentine 1 mk (ii) Has cusps/ ridges; to enable it grind / chew food; (into smaller pieces) (iii) Blood vesselsü

Nerve fibres ü

Food substance Procedure Observation Conclusion© Nyando District Examination Panel Biology 231/31

Head

Middle

Tail

Ascorbic acid To DCPIP , add the juice in drops ( and shake)

DCPIP decolourised, become colourless

Ascorbic acid/ Vit c present

Starch To the juice ( an a white tile) add drops of iodine solution

No colour change Starch present

Reducing sugar Add an equal amount of benedict solution to the juice and heat

Colour changes to yellow / orange

Reducing sugar present

Lipids Rub a drop of the juice on the filter paper . Dry

Retain original appearance

Lipid absent

marks = 6 marks

Conditions No mark for food substances Award marks for procedure if the reagents used are for the food substance correctly mentionedDo not award marks for procedure and conclusion if the procedure is wrong Reject: oil for lipids and any specific names for reducing sugars

b) (i) Overcooking denatures/ destroys vitamins 1 mark(ii) Scurvy 1 mark(iii) To filter out/ sieve the seeds 1 mark

(iv) Ileum; acc small j intestine 1 mark

Reject: intestinesWrong spelling

3 a) K- Pith 3 marks L – Cortex Q – Piliferous layer/epidermis;

b) R – XylemFunction: Transport water and mineral salts;Reject: Water alone or mineral salts alone.P – Phloem;Function: Translocation of manufactured food;Acc: Transport of food.

c)Young root Mature rootAbsence of root hairs on epidermisVascular tissue not fully differentiatedPresence of pith in the centre

Presence of root hairs on epidermisVascular tissue fully differentiatedAbsence of pith/centre occupied by xylem

3 marks

d) Anchorage/firm attachment to the ground;Absorption of water and mineral salts;Storage of food;Gaseous exchange; Mark first 3 3 marks

© Nyando District Examination Panel Biology 231/32