# Explain how the structure of an enzyme allows it to speed up a chemical reaction, and describe what happens to the enzyme if the temperature becomes too high.

> OCR GCSE Biology A: Gateway Science (J247) — B1.2 What happens in cells (and what do cells need) · Explain · 4 marks

> Amylase is an enzyme produced in the salivary glands. It breaks down carbohydrates into simple sugars during digestion.

## Mark scheme (4 marks)

1. The enzyme has an active site with a complementary shape to the substrate (carbohydrate/starch)
2. The substrate binds to the active site, forming an enzyme-substrate complex, which lowers the energy needed for the reaction (speeds up the reaction)
3. At very high temperatures the shape of the active site changes (permanently)
4. This process is called denaturation and the enzyme can no longer function normally

## Related

- [Revision notes for OCR GCSE Biology A: Gateway Science (J247)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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