Final answer:
The effect of a neurotransmitter on a target cell is determined by the receptor to which it is attached.
Step-by-step explanation:
The effect of a neurotransmitter on a target cell is entirely dependent on the receptor to which it is attached. Neurotransmitters bind to specific receptors on the cell surface, and the two fit together like a key and lock. The receptor can determine whether the neurotransmitter causes depolarization or hyperpolarization of the target cell.