Question

unit 4 - challenge 4.1: the nervous s
which of the following are contained in synaptic vesicles?
a.) ligand - gated channels
b.) enzymes
c.) neurotransmitters
d.) ca²+ ions
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Explanation:

Synaptic vesicles are small sacs located at the axon terminal of a neuron. Their primary function is to store and release neurotransmitters. Neurotransmitters are chemical messengers that transmit signals across a synapse from one neuron (nerve cell) to another target neuron, muscle cell, or gland cell.

• Ligand - gated channels are typically found on the postsynaptic membrane, not in synaptic vesicles. They open in response to the binding of a neurotransmitter (ligand).
• Enzymes involved in neurotransmitter synthesis or degradation are usually in the cytoplasm of the neuron (e.g., enzymes like acetylcholinesterase which degrades acetylcholine are in the synaptic cleft, not in vesicles).
• \(Ca^{2 +}\) ions play a role in the exocytosis of synaptic vesicles (when an action potential arrives, \(Ca^{2+}\) enters the neuron and triggers the release of vesicles), but \(Ca^{2+}\) ions are not stored in the synaptic vesicles.

Answer:

C. Neurotransmitters