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Multiple Choice
After nervous stimulation stops, what prevents acetylcholine (ACh) from continuing to stimulate the postsynaptic cell?
A
ACh is actively transported back into the presynaptic neuron.
B
Acetylcholinesterase breaks down ACh in the synaptic cleft.
C
ACh diffuses away from the synaptic cleft without being degraded.
D
ACh is converted into dopamine by synaptic enzymes.
Verified step by step guidance
1
Understand the role of acetylcholine (ACh) in synaptic transmission: ACh is a neurotransmitter that binds to receptors on the postsynaptic cell, initiating a response such as muscle contraction or neural signaling.
Recognize the importance of stopping the signal: After the nervous stimulation ends, ACh must be removed from the synaptic cleft to prevent continuous stimulation of the postsynaptic cell, which could lead to overstimulation or improper functioning.
Identify the mechanism responsible for breaking down ACh: Acetylcholinesterase is an enzyme located in the synaptic cleft that specifically breaks down ACh into acetate and choline, effectively terminating its activity.
Clarify why other options are incorrect: ACh is not actively transported back into the presynaptic neuron, nor does it diffuse away without being degraded. Additionally, ACh is not converted into dopamine; these processes are unrelated to ACh's role in synaptic transmission.
Conclude that acetylcholinesterase is the key factor in preventing ACh from continuing to stimulate the postsynaptic cell, ensuring proper regulation of neural signaling.