DP Biology (last assessment 2024)

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Question 22M.2.SL.TZ1.5b

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Date May 2022 Marks available [Maximum mark: 1] Reference code 22M.2.SL.TZ1.5b
Level SL Paper 2 Time zone TZ1
Command term State Question number b Adapted from N/A
b.
[Maximum mark: 1]
22M.2.SL.TZ1.5b

The graph shows the change in the membrane potential of an axon during an action potential.

(b)

Y is the threshold potential. State what happens when the threshold potential is reached.

[1]

Markscheme

sodium channels (start to) open
OR
depolarization/axon begins to depolarize
OR
action potential occurs;

Reject pumping of ions.

Examiners report

Fundamental terms such as action potential or depolarization were not used in Q5(b) and (c). Some candidates failed to distinguish between elements and ions.

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