# Explain how the shape of an enzyme allows it to catalyse a reaction, and describe what happens to enzyme activity when the temperature is increased well above the optimum.

> AQA A-Level Biology (7402) — 3.1.4 Proteins and Enzymes · Explain · 5 marks

## Mark scheme (5 marks)

1. Enzyme has an active site with a specific shape
2. The substrate is complementary to / fits into the active site
3. An enzyme-substrate complex is formed
4. Above the optimum temperature, the active site changes shape / the enzyme is denatured
5. The substrate can no longer fit into the active site, so the reaction rate decreases / stops

## Related

- [Revision notes for AQA A-Level Biology (7402)](https://www.gradenine.co.uk/learn)
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Source: [GradeNine](https://www.gradenine.co.uk/q/explain-how-the-shape-of-an-08458228) · Published by Druglandscape Ltd.