# Explain how enzymes in the digestive system break down a protein-rich meal into molecules that can be absorbed into the blood.

> AQA A-Level Biology (7402) — 3.3.3 Digestion and Absorption · Explain · 5 marks

> A student eats a meal containing a large amount of protein, such as a chicken breast. Proteins are large, insoluble molecules that must be digested before they can be used by the body.

## Mark scheme (5 marks)

1. Proteases are the enzymes that digest proteins
2. Proteases are produced in the stomach and/or pancreas and/or small intestine
3. Proteins are broken down into amino acids
4. Amino acids are small/soluble enough to be absorbed
5. Amino acids are absorbed into the blood through the wall of the small intestine

## Related

- [Revision notes for AQA A-Level Biology (7402)](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-how-enzymes-in-the-digestive-60f16801) · Published by Druglandscape Ltd.