waecE-LEARNING
Biology Paper 3,Nov/Dec 2013  
Questions:   1 2 3 4   Main
General Comments
Weakness/Remedies
Strength

















































Question 4

(a) The Table below shows parts of the alimentary canals possessed by different animals. Tick (?) the part possessed by the corresponding animal in the Table.

 

 

Animal

Parts of alimentary canal

Pharynx

Gullet

Crop

Stomach

Caecum

Rectum

1.

Planaria

 

 

 

 

 

 

2.

Earthworm

 

 

 

 

 

 

3.

Cockroach

 

 

 

 

 

 

4.

Tilapia

 

 

 

 

 

 

5.

Frog

 

 

 

 

 

 

6.

Lizard

 

 

 

 

 

 

7.

Bird

 

 

 

 

 

 

8.

Rabbit

 

 

 

 

 

 

9.

Cow

 

 

 

 

 

 

10.

Human

 

 

 

 

 

 

[17 marks]

(b) (i) State five functions of the stomach in humans. [5 marks]
(ii) Explain briefly the stages of holozoic nutrition in humans. [5 marks]

(c) State three effects of indigestion in humans. [3 marks]


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OBSERVATION

Many candidates performed well in question 4 (a). The performance was poor in 4 (b) (i) and candidates just listed the stages of holozoic nutrition in humans without explanation. The expected answers are:

(b) (i) Functions of stomach of Humans
- The stomach temporarily stores food;
- stomach secretes gastric juice containing hydrochloric acid; pepsin and rennin;
- hydrochloric acid provides acidic medium for protein digestion;
- hydrochloric acid destroys harmful bacteria in the stomach;
- rennin solidifies /curdles milk;
- pepsin digests protein into peptides in the stomach
- large particles of food are turned and broken down to smaller particles by the contraction of the stomach muscle/churning.


(ii) Stages of holozoic nutrition

Ingestion; taking in pieces of solid food into the mouth
Digestion: breaking down of large food particles by mechanical/chewing; enzymatic activites/chemical means into smaller particles/soluble that the body can absorb.
Absorption: taking up the soluble products of digestion into the blood;
Assimilation: using/utilization of the absorbed food materials by the body cells/tissues; Egestion: elimination of the undigested food materials through the anus.

(c) Effects of indigestion in humans
- causes constipation/inability to defaecate;
- bloated stomach;
- stomach ache;
- heartburn/burning sensation;
- general weakness;
- flatulence/release of gas.

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