# Explain how a nerve impulse is transmitted from one neurone to the next across a synapse.

> WJEC A-Level Biology (Wales) — 4.3 Variation and evolution · Explain · 5 marks

## Mark scheme (5 marks)

1. When a nerve impulse arrives at the end of the presynaptic neurone, a neurotransmitter is released
2. The neurotransmitter diffuses across the synaptic cleft
3. The neurotransmitter binds to receptors on the postsynaptic neurone
4. This triggers a new nerve impulse in the postsynaptic neurone
5. This means the impulse is propagated / continues along the nervous pathway

## 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)

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Source: [GradeNine](https://www.gradenine.co.uk/q/explain-how-a-nerve-impulse-is-2188158f) · Published by Druglandscape Ltd.