Which of the Following is Not True of Acetylcholine

Question

Which of the following is not true of acetylcholine?
A) It binds to receptor membrane channels.
B) It diffuses across the synaptic cleft.
C) It is stored in the neuron in vesicles.
D) It enters the muscle fiber to release calcium form the sarcoplasmic reticulum.
E) It is digested by acetylcholinesterase.

Accepted Answer

Acetylcholine does not enter the muscle fiber to release calcium from the sarcoplasmic reticulum. Rather, it binds to receptor membrane channels on the muscle fiber, which triggers the release of calcium from the sarcoplasmic reticulum. The other statements are true of acetylcholine: it binds to receptor membrane channels, diffuses across the synaptic cleft, is stored in the neuron in vesicles, and is digested by acetylcholinesterase.