Biological

Question 1

Synaptic transmission (2 marks + drawing)

Answer 1

An electrical impulse triggers the release of neurotransmitters from the vesicles. These travel across the synapse to the receptor sites of the post-synaptic neutron which acts in a lock and key mechanism to then pass the message on

Question 2

cocaine 4 marks

Answer 2

Cocaine works on the reward pathway and dopamine receptors within seconds.
With cocaine there is a reuptake by the presynaptic neutron of neurotransmitter left in the synapse - cocaine blocks the binding site on the receptor site (inhibitory) and stops the reuptake of dopamine into the presynaptic neurone. Which excess dopamine in the synapse which then leads to over-stimulation at the postsynaptic receptors
There is no foreign substance to bind to the dopamine receptors but there is more dopamine then usual