Final answer:
The extent of neurotransmitter binding to receptors on the postsynaptic membrane is primarily determined by the concentration of neurotransmitter. The correct answer is option (4).
Step-by-step explanation:
The extent of neurotransmitter binding to receptors on the postsynaptic membrane is primarily determined by the concentration of neurotransmitter.
Receptors are specific for particular neurotransmitters, and when a neurotransmitter binds to its receptor, a specific chemical event occurs.
The binding of a neurotransmitter to its receptor causes ligand-gated ion channels on the postsynaptic membrane to open, resulting in a localized depolarization or hyperpolarization of the postsynaptic neuron.