# Explain how the structure of a synapse allows a nerve impulse to pass from one neurone to the next.

> WJEC A-Level Biology (Wales) — 3.8 The nervous system · Explain · 5 marks

## Mark scheme (5 marks)

1. A nerve impulse arrives at the end of the pre-synaptic neurone (synaptic knob / pre-synaptic terminal)
2. This causes vesicles containing neurotransmitter to move to and fuse with the pre-synaptic membrane, releasing neurotransmitter into the synaptic cleft
3. The neurotransmitter diffuses across the synaptic cleft
4. Neurotransmitter binds to receptors on the post-synaptic membrane
5. This generates a new nerve impulse in the post-synaptic neurone

## Key terms

- [synapse](https://www.gradenine.co.uk/glossary/synapse)

## Related

- [Revision notes for WJEC A-Level Biology (Wales)](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-the-structure-of-a-1308b3f9) · Published by Druglandscape Ltd.