DP Biology (first assessment 2025)

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Question 20N.2.SL.TZ0.c.ii

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Date November 2020 Marks available [Maximum mark: 3] Reference code 20N.2.SL.TZ0.c.ii
Level SL Paper 2 Time zone TZ0
Command term Explain Question number c.ii Adapted from N/A
c.ii.
[Maximum mark: 3]
20N.2.SL.TZ0.c.ii

X indicates the movement of a structure in the neuron. Explain what events trigger this movement and what happens next.

[3]

Markscheme

a. depolarization of pre-synaptic membrane / action potential/nerve impulse arrives;

b. uptake of calcium / calcium ions diffuse in / calcium channels open;

c. structures containing neurotransmitter/vesicles move to/fuse with membrane;

d. neurotransmitter/acetylcholine released by exocytosis into cleft/binds to postsynaptic membrane/receptors;

Must see exocytosis.

Examiners report

This was generally well answered. Some suggested that the vesicle is released into the synaptic cleft, instead of neurotransmitter being released by exocytosis.

Syllabus sections