DP Biology (last assessment 2024)

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Question 22M.2.SL.TZ1.c

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

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

Describe the movements in ions that occur during time t.

[2]

Markscheme

Na+/sodium ions diffuse into the axon (in the first part/half of t);
K+ /potassium ions diffuse out of the axon (in the second half/part of t)

Do not accept the name of the element without indication that it is an ion.

Examiners report

Some candidates talked about ion movement but with no reference to a specific ion; some described the Na+/K+ pump here and received no marks.

Syllabus sections