# Explain why the large surface area of the ileum wall is important for the absorption of the products of digestion.

> Cambridge International IGCSE Biology (0610) — 7.5 Absorption · Explain · 4 marks

> The ileum is the main site of absorption in the alimentary canal. Its inner wall has many finger-like projections called villi, and each epithelial cell on the surface of a villus has further protrusions called microvilli.

## Mark scheme (4 marks)

1. A larger surface area means more molecules can pass through the wall of the intestine at the same time / per unit time.
2. This increases the rate of absorption / allows digested food to be absorbed more quickly / efficiently.
3. So that sufficient / enough nutrients (glucose, amino acids, fatty acids and glycerol) move into the bloodstream to meet the body's needs.
4. So that nutrients can be assimilated into cells and used in metabolic reactions / for energy / growth and repair.

## Key terms

- [absorption](https://www.gradenine.co.uk/glossary/absorption)
- [surface area](https://www.gradenine.co.uk/glossary/surface-area)
- [ileum](https://www.gradenine.co.uk/glossary/ileum)

## Related

- [Revision notes for Cambridge International IGCSE Biology (0610)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

---
Source: [GradeNine](https://www.gradenine.co.uk/q/explain-why-the-large-surface-area-c8fa5919) · Published by Druglandscape Ltd.