Question

How sodium-pottasiom pump returns membrane potential back to its resting potential and makes inside of the neuron more potentially possitive when three sodium ions are transported to the out of the cell and just two potassiom ions are transported back into the cell?

Answer 1

The sodium-potassium pump maintains a neuron's resting membrane potential by moving three Na+ out and two K+ in, creating a net negative charge inside. This action, along with more potassium leakage channels than sodium ones, keeps the inside of the cell negatively charged relative to the outside.

Step-by-step explanation:

The sodium-potassium pump is essential for maintaining the resting membrane potential of a neuron. A resting neuron is negatively charged compared to the outside, due to this pump actively moving three sodium ions (Na+) out of the cell and two potassium ions (K+) into the cell. This creates a net negative charge inside the cell, contributing to the resting potential of -70 mV. The energy required for this active transport comes from the hydrolysis of ATP. The pump's activity results in a higher concentration of sodium ions outside of the cell and a higher concentration of potassium ions inside, which is critical for nerve impulse transmission.

Potassium ions tend to leak out of the cell more than sodium ions leak in because there are more potassium leakage channels. This leakage further contributes to a negative charge inside the cell. The sodium-potassium pump and the differential permeability of sodium and potassium through their respective channels ensure that the cell's interior remains relatively negative, thus preserving the resting membrane potential.