Date | November 2018 | Marks available | 2 | Reference code | 18N.3.SL.TZ0.5 |
Level | Standard level | Paper | Paper 3 | Time zone | TZ0 / no time zone |
Command term | Describe | Question number | 5 | Adapted from | N/A |
Question
The drawings show the development of an immature neuron in a rat.
Describe the process taking place.
Outline the possible changes to this neuron that could happen during the subsequent development of the nervous system.
Suggest how the plasticity of the brain can benefit humans.
Markscheme
a. «the process shows» the growth of an axon/dendrites/extensions ✔
b. differentiation/forming a specialized neuron ✔
c. responding to a chemical stimulus ✔
a. the neuron forms synapses/multiple connections «with other neurons»
OR
a neural network forms
OR
more dendrites ✔
b. some synapses/connections in excess of what is required
OR
some synapses/connections not used ✔
c. it could be removed by neural pruning/apoptosis ✔
d. it could migrate to another place ✔
a. allows brain to change/adjust/make new synapses throughout lifetime/with experience/learning ✔
b. allows regeneration of neurons after brain trauma
OR
allows other area «of the brain» to take over a function after brain trauma ✔
c. selective advantage/increases chance of survival ✔
OWTTE