# Enzymes are biological catalysts made from chains of amino acids. Explain how the structure of an enzyme allows it to carry out its function, and describe what happens to enzyme activity when the temperature rises above the optimum.

> Eduqas A-Level Biology — 1.1 Chemical elements and biological molecules · Explain · 5 marks

## Mark scheme (5 marks)

1. Enzymes have an active site with a specific shape
2. The active site is complementary to the substrate
3. An enzyme-substrate complex forms when the substrate enters the active site
4. Above the optimum temperature, the active site changes shape / the enzyme denatures
5. The substrate can no longer fit the active site, so no enzyme-substrate complexes form and the rate of reaction decreases

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Source: [GradeNine](https://www.gradenine.co.uk/q/enzymes-are-biological-catalysts-made-from-4290912b) · Published by Druglandscape Ltd.