| Date | May 2013 | Marks available | 1 | Reference code | 13M.3.SL.TZ2.15 |
| Level | Standard level | Paper | Paper 3 | Time zone | Time zone 2 |
| Command term | State | Question number | 15 | Adapted from | N/A |
Question
State two effects that presynaptic neurons can have on postsynaptic transmission.
1. .............................................................
2. .............................................................
Suggest causes of addiction to drugs.
Markscheme
excite and inhibit (both needed)
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);
Examiners report
Few were able to give excite and inhibit as the two effects in 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.
