OCR A 5.1.3 · 12 written questions · 23 marks · about 30 minutes · marked as you go
This free quiz has 12 written exam questions on neuronal communication, all taken from OCR A Level Biology A papers (A level, 2018 to 2023, plus OCR practice or sample papers). The OCR bank has only a small number of written questions on this topic, so this quiz is shorter than most. Short answers mark themselves. For longer answers you write your answer, then tick off the OCR mark-scheme points you made, so you see exactly where the marks are. This quiz covers sensory receptors as transducers, motor neurones and myelination, the action potential and how a toxin blocks it, and the structure and role of synapses.
What the quiz covers (OCR A spec 5.1.3)
Sensory receptors (5.1.3(a)): pain receptors and a squid statocyst as transducers, and why naked mole rats don't feel acid pain.
Neurones (5.1.3(b)): identifying a type of neurone, the role of the myelin sheath, and why conduction is slower without saltatory conduction.
Nerve impulses (5.1.3(c)): positive feedback and depolarisation in the action potential, and how tetrodotoxin blocks voltage-gated sodium ion channels.
Synapses (5.1.3(d)): reading an electron micrograph of a synapse, evaluating evidence about Ca²⁺ ions and neurotransmitter release, and why botulinum toxin can be fatal.
How to use it
Write every answer in full, as you would in the exam: the mark for each question is shown, so you know how much to write. When you self-mark, only tick a point if your answer clearly makes it, then read the examiner's tip under each question. Your progress is saved on your device, so you can do it in two sittings, and at the end you can retry just the questions where you dropped marks.
Prefer multiple choice? Try the 22-question Neuronal and Hormonal Communication multiple choice quiz first.
Open the Neuronal Communication quiz in a new tab (easier on a phone)
Where students lose marks (from OCR examiners' reports and mark schemes)
Each point below is followed by wording that gained marks.
Fewer sodium ions, not none: Saying no Na⁺ ions enter, or no depolarisation happens, when only the voltage-gated channels are blocked and other channels can still open.
✔ Gains credit: Fewer Na⁺ ions move in, so there is less depolarisation of the receptor membrane.
Voltage-gated, in those words: Writing that 'fewer sodium ion channels open' without saying which channels, when it is the voltage-gated ones that matter for an action potential.
✔ Gains credit: No (or few) voltage-gated sodium ion channels open, so no action potential is generated.
Action potential, not 'message': Describing a failure to send a 'signal' or 'message' rather than using the correct term.
✔ Gains credit: No action potentials are generated, so no impulses pass along sensory neurones to the CNS.
Don't just restate the question: Answering why unmyelinated axons conduct slowly by saying the impulse can't jump from node to node, which the question has already said.
✔ Gains credit: Without nodes of Ranvier, depolarisation has to happen along the whole axon membrane.
Say it's the axon membrane: Explaining the effect of a sodium channel blocker without saying which membrane is not depolarised.
✔ Gains credit: Na⁺ ions cannot enter, so the axon membrane is not depolarised and stays at resting potential.
Apply it to the toxin: Describing what normally happens in a neurone instead of what happens when the channels are blocked, which OCR limits to 3 marks out of 4.
✔ Gains credit: Because the channels can't open, no action potential is generated, the impulse isn't conducted and no neurotransmitter is released.
Synaptic cleft, not synapse: Naming the gap between two neurones as just 'synapse', which isn't precise enough.
✔ Gains credit: Synaptic cleft (or synaptic gap).
Vesicles don't cross the cleft: Saying vesicles move across the synaptic cleft.
✔ Gains credit: Vesicles fuse with the presynaptic membrane and release neurotransmitter, which diffuses across the cleft.
Keep practising
Try the Neuronal and Hormonal Communication multiple choice quiz, the Plant and Animal Responses multiple choice quiz, the Homeostasis and Excretion written quiz or the Hormonal Communication written quiz, or browse all our OCR A Level Biology quizzes. Our OCR A masterclasses (Year 12 on Wednesdays at 5.15pm, Year 13 on Tuesdays at 6.30pm) work through real exam questions on one topic each week.
Questions, mark schemes and examiners' report extracts © OCR.