Biology 9700 · AS & A Level · Control and coordination in mammals

Control and coordination in mammals — practice question

Dopamine is a neurotransmitter that is released at certain synapses in the brain. Its release and action are comparable to those of acetylcholine. Fig. 9.1 shows a brain synapse in which dopamine acts as the neurotransmitter.
(a(i))[4]

Describe the way in which dopamine released from the presynaptic neurone can cause an action potential in the postsynaptic neurone.

(a(ii))[1]

In brain cells, the amino acid tyrosine is converted into DOPA, which is then turned into dopamine. Name another substance in the body that is made from DOPA.

(b)[3]

In some brain synapses, the neurotransmitter gamma-aminobutyric acid (GABA) is released. This causes chloride ions to flow into the postsynaptic neurone. Suggest and explain whether an action potential would be produced in the postsynaptic neurone if GABA were released into a brain synapse.

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