A graded potential is a change in the membrane potential that varies in size, depending on the strength of the stimulus. It is not a long-distance signaling mechanism but rather a local change that can initiate an action potential if it reaches the threshold.
The correct description of a graded potential is:
- Involves chemically or mechanically gated channels: Graded potentials are typically generated by the opening of chemically gated or mechanically gated ion channels. These channels allow ions to flow across the membrane, causing a change in the membrane potential.
Other options do not correctly describe a graded potential:
- Long-distance signaling: This describes action potentials, not graded potentials.
- Voltage stimulus to initiate: Graded potentials are initiated by chemical or mechanical stimuli, not voltage stimuli.
- Voltage-regulated repolarization: This refers to the process that occurs during the repolarization phase of an action potential, not a graded potential.