IGCSE Biology: Human Nutrition — Practice Questions

These are original practice questions written in the style of Cambridge IGCSE Biology (0610) assessment objectives. They are not taken from any past paper and are not endorsed by Cambridge International.

Use these questions alongside the Human Nutrition study guide and revision notes. Section A targets Core content that both tiers must know; Section B mixes Core and Supplement material, with Supplement-only parts marked.

Section A — Core

1. State three of the seven nutrients listed in the Cambridge syllabus that a balanced diet must supply, and give one dietary importance for each. [3]

2. Name the deficiency disease caused by a lack of vitamin C, and the deficiency disease caused by a lack of vitamin D. [2]

3. List, in order, the parts of the alimentary canal a mouthful of food passes through from the mouth to the anus. [4]

4. Define egestion, and explain why it is not the same process as excretion. [3]

5. State two functions of hydrochloric acid in gastric juice. [2]

Section B — Core and Supplement

6. A student chews a piece of bread thoroughly before swallowing it, rather than swallowing it whole.

(a) Explain why chewing is described as physical digestion rather than chemical digestion. [2] (b) Explain how chewing makes the chemical digestion of the bread’s starch more effective once it reaches the small intestine. [2]

7. Complete the missing substrate or product for each enzyme.

Enzyme	Substrate	Product(s)
Amylase	Starch	?
Protease	?	Amino acids
Lipase	Fats and oils	?

[3]

8. (Supplement) Pepsin and trypsin are both proteases, but they work in different regions of the alimentary canal.

(a) State where pepsin acts, and the pH conditions it requires. [2] (b) State where trypsin acts, and the pH conditions it requires. [2] (c) Explain how bile makes the small intestine’s conditions suitable for trypsin to work, given that the stomach contents entering the duodenum are acidic. [2]

9. (Supplement) A villus in the small intestine wall contains both a network of capillaries and a lacteal.

(a) State which digestion products are absorbed by the capillaries, and which are absorbed by the lacteal. [2] (b) Suggest two features of the small intestine’s internal surface that increase the rate of absorption. [2]

10. A doctor tells a patient that their diet lacks enough calcium and iron.

(a) State one importance of calcium and one importance of iron in the body. [2] (b) Suggest one dietary change the patient could make to correct each deficiency. [2]

---

Answers

1. Any three of: carbohydrates (energy) [1]; fats and oils (energy store, insulation) [1]; proteins (growth and repair) [1]; vitamin C (prevents scurvy) [1]; vitamin D (prevents rickets) [1]; calcium (bones and teeth) [1]; iron (haemoglobin production) [1]; fibre (aids movement of food through the gut) [1]; water (solvent, transport medium) [1]. (Maximum 3 marks for three correctly paired nutrients and importances.)

2. Vitamin C deficiency causes scurvy [1]; vitamin D deficiency causes rickets [1].

3. Mouth → oesophagus → stomach → small intestine (duodenum then ileum) → large intestine (colon then rectum) → anus [4, allow 1 mark per correctly ordered pair of adjacent regions].

4. Egestion is the removal of undigested food from the body as faeces [1]. It differs from excretion because egestion removes food that was never absorbed into the body at all [1], whereas excretion removes waste substances produced by the body’s own metabolism, such as in the kidneys and lungs [1].

5. Hydrochloric acid kills harmful microorganisms present in food [1], and it provides the acidic pH needed for the stomach’s protein-digesting enzymes to work at their optimum [1].

6. (a) Chewing breaks the bread into smaller pieces without changing the chemical structure of the starch molecules themselves, so it is physical, not chemical, digestion [2]. (b) Breaking the bread into smaller pieces increases its surface area [1], so more starch molecules are exposed to amylase per unit time, allowing chemical digestion to happen faster once the bread reaches the small intestine [1].

7. Amylase → simple reducing sugars [1]; Protease substrate → protein [1]; Lipase → fatty acids and glycerol [1].

8. (a) Pepsin acts in the stomach [1], in acidic conditions [1]. (b) Trypsin acts in the small intestine [1], in alkaline conditions [1]. (c) Bile is alkaline, so when it mixes with the acidic stomach contents entering the duodenum it neutralises the acid [1], raising the pH to the alkaline range in which trypsin and the small intestine’s other enzymes work best [1].

9. (a) Capillaries absorb sugars and amino acids [1]; the lacteal absorbs fatty acids and glycerol [1]. (b) Any two of: the small intestine is folded [1]; it is covered in villi [1]; villi are covered in microvilli [1]; each of these increases the surface area available for absorption.

10. (a) Calcium is needed for strong bones and teeth [1]; iron is needed to make haemoglobin, the protein in red blood cells that carries oxygen [1]. (b) Any suitable suggestion, for example: eating more dairy products, leafy green vegetables or fortified foods for calcium [1]; eating more red meat, leafy green vegetables or fortified cereals for iron [1].

A note on exam technique for this topic

Human Nutrition rewards candidates who treat the digestive system as a single connected pathway rather than five separate facts to memorise. When a question gives you an unfamiliar scenario — a patient with a specific deficiency, an unusual enzyme name, or a diagram of a villus you have not seen labelled exactly that way before — work back to which of the five sub-topics it belongs to and apply the general rule you have learned (substrate to product for enzymes, direction and energy requirement for absorption routes) rather than searching your memory for an identical past-paper question. The two most repeatedly tested confusions in this topic — egestion versus excretion, and physical versus chemical digestion — are worth deliberately rehearsing out loud in your own words until you can state the distinction without hesitation, since examiners return to these exact confusions across multiple exam series.