The following steps refer to various stages in transmission at a chemical synapse. 1. Neurotransmitter binds with receptors associated with the postsynaptic membrane.
2) Calcium ions rush into the neuron's cytoplasm.
3) An action potential depolarizes the membrane of the axon terminal.
4) The ligand-gated ion channels open.
5) The synaptic vesicles release neurotransmitter into the synaptic cleft.
Which sequence of events is correct?
A) 1 → 2 → 3 → 4 → 5
B) 2 → 3 → 5 → 4 → 1
C) 3 → 2 → 5 → 1 → 4
D) 4 → 3 → 1 → 2 → 5
E) 5 → 1 → 2 → 4 → 3

Question

Quizplus · Accepted Answer

The correct sequence of events in the transmission at a chemical synapse is 3 → 2 → 5 → 1 → 4. An action potential depolarizes the membrane of the axon terminal (3), which leads to the opening of voltage-gated calcium channels allowing calcium ions to rush into the neuron's cytoplasm (2). The calcium influx triggers the fusion of synaptic vesicles with the presynaptic membrane and release of neurotransmitter into the synaptic cleft (5). The neurotransmitter diffuses across the synaptic cleft and binds to receptors associated with the postsynaptic membrane (1). This binding leads to the opening of ligand-gated ion channels (4) and the generation of a postsynaptic potential.

The Following Steps Refer to Various Stages in Transmission at a Chemical