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BIOLOGY FORM THREE
Marking scheme
Question 1
(a) Omnivorous; (1mk)
(b) I – Molar; (1mk)
II – Canine; (1mk)
(c) H – Enamel / crown; (1mk)
J – Neck; (1mk)
(d) Teeth II has flat top / ridged while tooth IV has chisel shaped top. (1mk)
(e) Cutting / biting (1mk)
(f) i2 c3 pm2 m3 x 2 = 32 (1mk)
2 3 2 3
(g) Used more for chewing / has greater contact with food particles; // is flat broad ridged / cusped holds food remains;
Question 2
(a) (i)
(ii) mg = Drawing length = 20mm
Objects length 10mm
= x 2;
- (i) Plantae;
- Bryophyta;
- Presence of;
Rhizoids;
Male and female branches
- – Leaves – photosynthesis
- Capsule – spore producing
- Rhizoids – anchorage, absorption of water and mineral salts.
- Green contains chlorophyll for photosynthesis;
- Sporulation
- Green hence carry out photosynthesis / autotrophic
Question 3
Test – tube | OBSERVATIONS | CONCLUSION |
A | Blue black/blue /black/bluish black; | Starch present; |
B | Blue black/blue /black/bluish black; | Starch present; |
C | Blue black/blue /black/bluish black; | Starch present; |
6/2 = 3 marks
(b)
Test – tube | OBSERVATIONS | CONCLUSION |
A | Blue black/blue /black/ dark blue / bluish black; | Starch present; |
B | No colour change /brown/yellow colour / colour of iodine; | Starch present; |
C | Blue black/blue /black/bluish black; | Starch present; |
6 marks
(c) Control experiment
(d) (i) Distase / enzyme /starch digesting enzyme/ ptyalin / saliva enzyme /salivary enzyme; (1mark)
(ii) Because it is converted / digested / changed starch / can be denatured by boiling / acts within a range of temperature between 35 0C – 380C / optimum temperature; only 1 (1 mark)
(e) Mouth / duodenum / ileum;
NB (f) tied to table (b)
- B – Starch absent / No colour change /colour of iodine remains because starch has been digested / converted / hydrolysed / broken down into glucose / maltose / simple sugar; (1mark)
C – Starch present because boiling denatured enzyme /L2 ; thus starch not broken down / not digested / not acted upon;