DP Biology (last assessment 2024)

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Question 19N.3.SL.TZ0.d

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Date November 2019 Marks available [Maximum mark: 2] Reference code 19N.3.SL.TZ0.d
Level SL Paper 3 Time zone TZ0
Command term Explain Question number d Adapted from N/A
d.
[Maximum mark: 2]
19N.3.SL.TZ0.d

The development of the neural tube in the frog Xenopus is shown in the diagram.

[Source: reprinted by permission from Nature Reviews Neuroscience, Gammill, L., Bronner-Fraser, M.
Neural crest specification: migrating into genomics. Nat Rev Neurosci 4, 795–805 (2003) doi:10.1038/nrn1219]

Explain how the nervous system develops from the cells of the neural tube.

[2]

Markscheme

a. neurons differentiate from neural tube / stem cells ✔

b. axons/dendrites grow ✔

c. «axon growth is» directed by chemicals/growth substances ✔

d. neurons migrate ✔

e. synapses form ✔

Syllabus sections