IB Biology SL 2.2.7 Excitatory postsynaptic potentials Question Bank

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

Exam points

Explain how neurotransmitters cross a synapse to reach the postsynaptic membrane.
Describe how ion movement generates an excitatory postsynaptic potential.

[Maximum number: 3]

The diagram shows a neuron.

Figure for Question C2.2.7—Excitatory postsynaptic potential 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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C2.2.7—Excitatory postsynaptic potential question 1