Question

At the target, neurotransmitter ________.

1) binds to receptor proteins
2) causes membrane channels to open or close
3) causes a change in membrane potential
4) does all of the above

Answer 1

At the target, neurotransmitters bind to receptors, cause ion channels to open or close, and affect membrane potentials, hence the correct answer is (4) they do all of the above.

Step-by-step explanation:

At the target, a neurotransmitter fulfills several functions such as (1) binding to receptor proteins, (2) causing membrane channels to open or close, and (3) causing a change in membrane potential. For example, the neurotransmitter acetylcholine binds to ionotropic receptors like the nicotinic receptor at neuromuscular junctions and results in the opening of sodium (Na+) channels, leading to depolarization and potentially triggering an action potential. Alternatively, neurotransmitters can have inhibitory effects, such as when GABA binds to its receptors and opens chlorine (Cl-) channels, leading to hyperpolarization of the membrane.

The neurotransmitter binds to receptor proteins on the postsynaptic membrane. This binding causes ligand-gated ion channels to open or close, allowing ions to enter or exit the cell. The movement of ions causes a change in membrane potential, leading to either depolarization or hyperpolarization of the postsynaptic membrane. Therefore, the correct answer is option 4) does all of the above.