Question

The membrane potential of a resting neuron is:

• A. -20 and -60 millivolts
• B. -30 and -80 millivolts
• C. -20 and -80 millivolts
• D. -60 and -80 millivolts

Hint:

For a resting neuron, remember the number \textbf{-70 mV} as the classic textbook value. This will help you quickly identify the correct range, which is -60 to -80 mV. The negative sign is crucial; it means the inside of the cell is negative compared to the outside.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
The resting membrane potential is the electrical potential difference across a nerve cell's plasma membrane when it's at rest. This potential is crucial for neuronal signaling.
Step 2: Detailed Explanation:


The resting membrane potential is established by the membrane's selective permeability to ions, mainly potassium (K\(^+\)) and sodium (Na\(^+\)), and the activity of the Na\(^+\)/K\(^+\) pump.

At rest, the neuron's membrane is far more permeable to K\(^+\) than Na\(^+\) due to open K\(^+\) leak channels.

K\(^+\) ions, highly concentrated inside the cell, diffuse outward, following their concentration gradient. This leaves behind negative anions, such as proteins, inside the cell.

This outward movement of positive charge makes the inside of the membrane negatively charged relative to the outside.

The resting membrane potential typically ranges from -60 to -80 millivolts (mV) in most neurons, with -70 mV being a common average.

Other ranges are not typical for a neuron's resting potential.

Step 3: Final Answer:
A resting neuron's membrane potential usually falls between -60 and -80 millivolts.