# Explain how the specificity of enzymes arises from their molecular structure, and state one consequence of this specificity for metabolic pathways.

> IB DP Biology Standard Level (2023 syllabus) — C1.1 Enzymes and metabolism · Explain · 4 marks

## Mark scheme (4 marks)

1. Enzymes are globular proteins with a specific three-dimensional (tertiary) structure.
2. The active site has a shape complementary to that of the specific substrate, allowing the enzyme–substrate complex to form.
3. Interactions (e.g. hydrogen bonds, ionic bonds) form between R-groups / amino acids of the active site and the substrate, stabilising the complex.
4. One consequence: each reaction in a metabolic pathway is catalysed by a different, specific enzyme, allowing precise regulation / control of the pathway.

## Key terms

- [metabolic pathway](https://www.gradenine.co.uk/glossary/metabolic-pathway)
- [specificity](https://www.gradenine.co.uk/glossary/specificity)

## Related

- [Revision notes for IB DP Biology Standard Level (2023 syllabus)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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Source: [GradeNine](https://www.gradenine.co.uk/q/explain-how-the-specificity-of-enzymes-1bdb8fc3) · Published by Druglandscape Ltd.