Question

Which of the following factors does not contribute towards establishing the resting potential of a neuron?
1. The Na+/K+ pump.
2. Passive K+ channels.
3. Selective permeability of ions across the membrane.
4. Voltage-gated Na+ channels.

Answer 1

Answer:

Voltage-gated Na+ channels.

Explanation:

Voltage-gated Na+ channels are largely closed at rest, and so they do not contribute to the resting potential.

Answer 2

Answer:

Option 4 – voltage gated Na+ channels is the right answer.

Explanation:

• When a neuron is not undergoing any change in the electrical potential. i.e., no impulse is running or generated at the membrane, it is known as Resting Potential.

• Due to stimuli generation, difference in sodium and potassium gradient results in generation of an electrical impulse and thereafter conduction of an impulse.

• K+ ions build up inside the cell while the membrane is at rest, as a result of a net movement, with the concentration gradient and sodium ions are kept at high concentrations outside of the cell in neurons. The two cations can diffuse down their concentration gradient thanks to potassium and sodium pump that are present in the cell which helps in maintaining the resting potential.

• Voltage gated channels are closed during resting potential, thereby, have no role in resting potential.

Hence, voltage gated sodium channels have no role in establishing the resting potential of a neuron.

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