QUESTIONS

(a) Once information has been transmitted across a synapse there is a delay before more information can be transmitted across the same synapse. This is because the neurotransmitter must be removed from the synaptic cleft (often by an enzyme) to prepare the synapse for the arrival of the next action potential. In a cholinergic synapse the neurotransmitter is acetylcholine which is removed by being broken down by a specific enzyme. Nerve gases used in warfare (e.g., sarin) achieve their effects by inhibiting this enzyme thus allowing acetylcholine to remain active. Atropine is used as an antidote to nerve gases
(i) Name the enzyme which operates in synapses to break down acetylcholine

(1)

 

(ii) The effects of nerve gases are irreversible. Suggest what type of inhibition occurs between nerve gas and acetylcholine, explain you answer.

(4)

 

(iii) Suggest how atropine can act as an antidote to nerve gases

(1)

 

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