DP Biology (first assessment 2025)
Question 20N.2.HL.TZ0.3b.ii
Date | November 2020 | Marks available | [Maximum mark: 3] | Reference code | 20N.2.HL.TZ0.3b.ii |
Level | HL | Paper | 2 | Time zone | TZ0 |
Command term | Explain | Question number | b.ii | Adapted from | N/A |
b.ii.
[Maximum mark: 3]
20N.2.HL.TZ0.3b.ii
(b.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;
