The activity of acetylcholine in a synapse is terminated by its
A) active transport across the presynaptic membrane.
B) diffusion across the presynaptic membrane.
C) active transport across the postsynaptic membrane.
D) diffusion across the postsynaptic membrane.
E) degradation by a hydrolytic enzyme on the postsynaptic membrane.

Question

Quizplus · Accepted Answer

Acetylcholine is degraded by a hydrolytic enzyme called acetylcholinesterase, which is present on the postsynaptic membrane. This enzyme breaks acetylcholine into acetate and choline, which can be taken back into the presynaptic neuron and reused for synthesizing more acetylcholine. Therefore, option E is the best choice. The other options (A, B, C, and D) are incorrect as they do not explain the actual mechanism of acetylcholine termination in the synapse.

The Activity of Acetylcholine in a Synapse Is Terminated by Its