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Date May 2013 Marks available 3 Reference code 13M.3.SL.TZ2.15
Level Standard level Paper Paper 3 Time zone Time zone 2
Command term Suggest Question number 15 Adapted from N/A

Question

State two effects that presynaptic neurons can have on postsynaptic transmission.

1.  .............................................................
2.  .............................................................

 

[1]
a (ii).

Suggest causes of addiction to drugs.

 

[3]
c.

Markscheme

excite and inhibit (both needed)

a (ii).

a. dopamine stimulates brain’s reward system/pathways / addiction requires dopamine excess in brain;
b. inhibitory drugs/benzodiazepines/alcohol/drugs decrease neuron activity that inhibits dopamine release so brain becomes addicted;
c. excitatory drugs/cocaine/amphetamines/nicotine block removal of dopamine stimulating brain (reward system);
d. genetic component involved;
e. genetic tendency for addiction influenced by social factor/example of social factor (eg peer pressure, poverty, social deprivation, trauma, mental health problem/culture);

c.

Examiners report

Few were able to give excite and inhibit as the two effects in a(ii).

a (ii).

In c the genetic components and the effects of social pressure were well known. Many knew that the cause was linked to dopamine, but did not explain in sufficient detail.

c.

Syllabus sections

Option A: Neurobiology and behaviour » Option A: Neurobiology and behaviour (Additional higher level topics) » A.5 Neuropharmacology
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