Final answer:
The statement is true; neurotransmitters are synthesized in the cytosol and then packed into synaptic vesicles, subsequently being released into the synaptic cleft to transmit signals to the next neuron.
Step-by-step explanation:
The statement that most neurotransmitters are synthesized in the cytosol and actively transported into synaptic vesicles is true. Neurotransmitters are chemical messengers that are crucial for the transmission of signals across the synaptic cleft from the presynaptic neuron to the postsynaptic neuron.
They are generally synthesized in the cytosol of the presynaptic neuron and then packed into synaptic vesicles. When an action potential arrives at the terminal button of the neuron, it triggers these vesicles to fuse with the presynaptic membrane, releasing the neurotransmitters into the synaptic cleft.
The released neurotransmitters then diffuse across the synapse and bind to receptor proteins on the postsynaptic membrane, which can trigger or inhibit action potentials in the postsynaptic neuron.