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Question 19M.3.SL.TZ1.5b

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Date May 2019 Marks available [Maximum mark: 4] Reference code 19M.3.SL.TZ1.5b
Level SL Paper 3 Time zone TZ1
Command term Outline Question number b Adapted from N/A
b.
[Maximum mark: 4]
19M.3.SL.TZ1.5b
(b)

Neurons are initially produced by differentiation in the neural tube. Outline the mechanisms of axon and synapse development that follow the initial creation of neurons.

[4]

Markscheme

a. axons are extensions of the neuron cell body ✔ 

b. some axons grow out of the neural tube and connect to other parts of the developing embryo ✔

c. chemical stimuli affect axon growth ✔

d. more dendrites form ✔

e. axon reaches the target cell ✔

f. forms single/multiple synapse«s» ✔

g. neural pruning involves the loss of neurons/synapses ✔

Do not accept migration of neurons

Examiners report

The question was often not read properly, with answers describing formation and migration of neurons, and chronological steps were rarely seen. Most answers receiving credit involved synapse formation and neural pruning.