IGCSE Biology: Human Nutrition Practice Questions
Human nutrition covers the balanced diet, the organs of the alimentary canal, and how digestion breaks large insoluble food molecules into small soluble ones that can be absorbed into the blood and used by cells.
This is one of the heaviest recall topics in Cambridge IGCSE Biology 0610, and it is also where answers most often lose marks for being vague. Examiners want named enzymes, named organs, named products and a stated reason. The four questions below are written in the style of Paper 2 and Paper 4 structured questions, with the mark allocation shown so you can check your method rather than just your answer.
What you need to know for Human Nutrition
- Balanced dietA diet containing carbohydrates, fats, proteins, vitamins, mineral ions, fibre and water in the correct proportions for age, sex and activity level.
- Physical and chemical digestionPhysical digestion breaks food into smaller pieces to increase surface area, using teeth and the churning of the stomach. Chemical digestion uses enzymes to break large insoluble molecules into small soluble ones.
- The three enzyme groupsAmylase breaks starch into maltose. Protease breaks protein into amino acids. Lipase breaks fats into fatty acids and glycerol.
- BileAn alkaline liquid made in the liver and stored in the gall bladder. It neutralises stomach acid and emulsifies fats. Bile is not an enzyme.
- Absorption and assimilationAbsorption is the movement of digested food into the blood through the wall of the small intestine. Assimilation is the uptake and use of those molecules by cells.
- Key deficiency diseasesNot enough vitamin C causes scurvy. Not enough vitamin D or calcium causes rickets. Not enough iron causes anaemia.
IGCSE Biology Human Nutrition questions and answers
4 exam-style questions written to the 0610 syllabus. Try each one on paper first, then open the worked answer to check your method against the marks.
State the two functions of bile and explain how each one helps the digestion of fat.
Show the worked answer
- Bile is made in the liver, stored in the gall bladder and released into the duodenum.
- It neutralises the hydrochloric acid arriving from the stomach, giving the slightly alkaline pH at which pancreatic lipase works best.
- It emulsifies fat, breaking large fat droplets into many small droplets.
- Many small droplets have a much larger total surface area than one large droplet, so lipase acts on more fat at once and digestion is faster.
Explain how the structure of a villus is adapted for the absorption of digested food.
Show the worked answer
- The small intestine is lined with millions of villi, and each villus is covered in microvilli, giving a very large surface area for absorption.
- The wall of a villus is one cell thick, so the diffusion distance into the blood is short.
- A dense network of capillaries carries absorbed glucose and amino acids away quickly, maintaining a steep concentration gradient.
- A lacteal in the centre absorbs fatty acids and glycerol into the lymphatic system.
A teenager eats very little red meat or green vegetables. Name the deficiency disease this may cause and explain why it makes her feel tired.
Show the worked answer
- Iron is needed to make haemoglobin in red blood cells.
- Without enough iron the body makes less haemoglobin, so the blood carries less oxygen.
- Cells receive less oxygen, so the rate of aerobic respiration falls and less energy is released, causing tiredness.
Name the enzyme that digests starch, state two places in the body where it is produced, and name the product of the reaction.
Show the worked answer
- Amylase is a carbohydrase that acts on starch.
- It is secreted by the salivary glands into the mouth and by the pancreas into the small intestine.
- Amylase breaks starch down into the disaccharide maltose, which maltase then breaks into glucose.
Common mistakes in this topic
- Confusing digestion with absorption. Digestion breaks molecules down. Absorption moves them into the blood.
- Naming an organ when the question asks for a gland, or the other way round. The pancreas is a gland, the duodenum is part of the alimentary canal.
- Describing bile as an enzyme.
- Giving "protein" as the product of protease instead of amino acids.
- Writing about the large intestine absorbing digested food. The large intestine absorbs water. Digested food is absorbed in the small intestine.
Exam tips
- Learn the enzyme table as a grid: enzyme, site of production, substrate, product. Most marks in this topic come straight from that grid.
- When a question says "explain", every mark needs a because. Adaptation plus advantage.
- Use the exact command word. "State" needs one line. "Describe" needs the what. "Explain" needs the why.
- For deficiency questions, always name the nutrient, the disease and one symptom.
- Check the mark allocation before writing. Four marks means four separate scoring points, not one point written four ways.
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Human Nutrition FAQs
What is the difference between digestion and absorption in IGCSE Biology?
Digestion is the breakdown of large insoluble food molecules into small soluble molecules, using physical and chemical processes. Absorption is the movement of those small molecules through the wall of the small intestine into the blood or the lacteal. Digestion happens first, and mostly in the mouth, stomach and duodenum.
Where is each digestive enzyme produced?
Amylase is produced in the salivary glands and the pancreas. Protease is produced in the stomach as pepsin, in the pancreas, and in the small intestine. Lipase is produced in the pancreas and the small intestine. Cambridge expects the site of production as well as the enzyme name.
Why is bile important if it is not an enzyme?
Bile neutralises the acid arriving from the stomach so that pancreatic enzymes work at their optimum pH, and it emulsifies fat into small droplets. Emulsification increases the surface area available to lipase, which speeds up fat digestion without breaking any bonds itself.
How much detail does IGCSE want on vitamin and mineral deficiencies?
For 0610 you need vitamin C and scurvy, vitamin D and rickets, calcium for bones and teeth, and iron for haemoglobin with anaemia as the deficiency. You should be able to name a dietary source and the effect on the body for each.
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Written to the published Cambridge IGCSE Biology (0610) syllabus. Check your school entry code and syllabus year, because Core and Extended candidates are assessed on different content. Last reviewed 2026-08-12.