Question

Exocytosis, or the release of neurotransmitter molecules from terminal buttons, is often triggered by

A) An influx of calcium ions
B) An influx of sodium ions
C) An influx of potassium ions
D) An influx of chloride ions

Answer 1

Exocytosis, the release of neurotransmitter molecules, is triggered by an influx of calcium ions (Ca²+). Voltage-gated calcium channels in the axon terminals open during an action potential, allowing calcium ions to enter the cell. The increase in calcium concentration leads to the fusion of synaptic vesicles with the presynaptic membrane and the release of neurotransmitters into the synaptic cleft.

Step-by-step explanation:

Exocytosis, or the release of neurotransmitter molecules from terminal buttons, is often triggered by an influx of calcium ions (Ca²+). When an action potential reaches the axon terminals, voltage-gated calcium channels open, allowing calcium ions to enter the cell. This increase in intracellular calcium concentration causes synaptic vesicles to fuse with the presynaptic membrane and release neurotransmitter molecules into the synaptic cleft.