IB Biology SL C2.2.7 Excitatory Postsynaptic Potential Questions

Practise IB Biology SL 2.2.7 by explaining how neurotransmitters generate an excitatory postsynaptic potential.

Exam points

Explain how neurotransmitters diffuse across the synaptic cleft and bind to receptors on the postsynaptic membrane.
Explain how postsynaptic ion movement depolarizes the membrane and makes threshold more likely, generating an excitatory postsynaptic potential.

[Maximum number: 3]

The diagram shows a neuron.

Figure for Question IB Biology SL C2.2.7 Excitatory Postsynaptic Potential Questions question 1 — IB Biology SL

Describe how an excitatory postsynaptic potential is generated.

Up to one additional mark is available for the construction of your answer.

a. calcium/ $\mathrm{Ca}^{2+} / \mathrm{Ca}$ moves into the presynaptic membrane
OR
neurotransmitter/acetylcholine released from presynaptic membrane;
b. (neurotransmitter) diffuses across the synapse/synaptic cleft;
c. binds to transmembrane receptors/receptors in postsynaptic membrane;
d. (protein) channels open/ Na+ /positive ions diffuse in;
e. causes depolarization (of (post synaptic) membrane) / action potential / membrane potential increases;
3

Marking guidance:

max
Clarity of communication: [1]
The candidate's answers are clear enough to be understood without re-reading. The candidate has answered the question succinctly with little or no repetition or irrelevant material.

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IB Biology SL C2.2.7 Excitatory Postsynaptic Potential Questions question 1