(A) (i) How does Paramecium obtain its food ?
(ii) List the role of each of the following in our digestive system :
(a) Hydrochloric acid
(b) Trypsin
(c) Muscular walls of stomach
(d) Salivary amylase
Generated by claude-sonnet-4-6 · 2026-06-11 09:50 · grounding rag
Model Answer
(A)(i) In Paramecium, food is taken in at a specific spot on the cell. Cilia covering the entire surface of the cell move and direct food particles to this spot, where they are ingested.
(ii)
(a) Hydrochloric acid – Creates an acidic medium in the stomach that facilitates the action of the enzyme pepsin.
(b) Trypsin – A pancreatic enzyme that digests proteins in the small intestine.
(c) Muscular walls of stomach – Help in mixing food thoroughly with digestive juices.
(d) Salivary amylase – Breaks down starch (complex carbohydrate) into simple sugars in the mouth.
Source: Chapter 5, Section 5.2.3 and 5.2.4
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Explanation
- For Paramecium, the key points are: definite shape, food taken at a specific spot, and role of cilia — all three should be mentioned.
- For part (ii), each sub-point is worth roughly ½ mark, so one crisp line per item is enough.
- Examiners look for the correct enzyme–substrate pair: amylase→starch, trypsin→proteins, pepsin (activated by HCl)→proteins.
- Avoid confusing pepsin (stomach) with trypsin (pancreas/small intestine).