Action Potentials and Synapse Biology Practice Test

Which of the following is characteristic of a chemical synapse?

I. Signal transmission involves neurotransmitters

II. They are bidirectional

III. They are more common than electrical synapses

In humans, nerve impulses are transmitted with the coordinated action of sodium and potassium ion channels. These channels open in a specific sequence, to allow for membrane potential changes to take place in a directional manner along the length of an axon.

Figure 1 depicts a single phospholipid layer of a cell membrane, and three transmembrane channels important to action potential propagation.

At the distal end of the axon shown in Figure 1, what process directly drives the fusion of synaptic vesicles to discharge neurotransmitter into the synaptic cleft?