Explain how a synapse allows a nerve impulse to pass from one neurone to the next.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Model answer (4 marks)
1. The nerve impulse reaches the end of the pre‑synaptic neuron.
2. Neurotransmitter is released into the synaptic gap.
3. It binds to receptors on the post‑synaptic neuron.
4. A new nerve impulse is generated in the post‑synaptic neuron.
2. Neurotransmitter is released into the synaptic gap.
3. It binds to receptors on the post‑synaptic neuron.
4. A new nerve impulse is generated in the post‑synaptic neuron.
Examiner tips
- Use the exact sequence of events; include the synaptic gap and receptor binding.
- Show the direction of the impulse – pre‑ to post‑synaptic.
- Mention neurotransmitter release as a key step.
- Keep the answer concise and to the point.
Common mistakes
- Omitting the synaptic gap or receptor binding.
- Confusing the direction of the impulse.
- Using vague terms like "signal" instead of "nerve impulse".
Mark scheme (4 marks)
- Nerve impulse arrives at / reaches the end of the first (pre-synaptic) neurone
- Neurotransmitter is released into the synaptic gap
- Neurotransmitter binds to receptors on the next (post-synaptic) neurone
- A new nerve impulse is generated / triggered in the next neurone
Key terms in this question
Related
- All Eduqas GCSE Biology revision notes →
- How to answer a "Explain" question →
- Decode the mark scheme abbreviations →