Summative Practice Chapter 9 – Question 1 – 3 (Form 4 Biology Textbook Exercise and Answer)

Question 1:
Some people cannot drink milk because it causes diarrhoea and a bloated stomach. Explain why.

The intestinal juice of the individual may possibly not contain or lacks lactase to digest milk sugar (lactose) in the small intestine. As a result, the bacteria in the large intestine will digest the lactose to yield fatty acids and methane which causes diarrhoea and bloating. The individual is advised to drink lactose-free milk.

Question 2:
Amin had some meat dishes for lunch. Explain how the protein is digested in Amin’s stomach.

• The gastric glands in the stomach secrete gastric juice.

• Gastric juice contains hydrochloric acid and pepsin.

• The medium in the stomach is acidic and optimum for enzyme action.

• Protein is hydrolysed into polypeptides by pepsin.

Question 3:
An individual has the following eating habits:

Overeating in a short period of time followed by intentional throwing up on purpose after each meal.

Explain how this eating habit can affect the health of this individual.

• The individual suffers from bulimia.

• To retain his/her body mass, the patient induces purging.

• The patient also experiences stress and anxiety.

• The patient suffers from an imbalance of mineral ions in the blood.

• This causes damage to the alimentary canal.

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