Question

Explain why ATPases (such as the sodium-potassium pump) are required for long term maintence of difference in ion concentration in the extracellular and intracellular fluids?

Answer 1

Sodium and potassium ions are pumped in opposite directions across the membrane as a result of which a chemical and electrical gradient is built up for each. These gradients are used to drive other transport processes. In order to move the Na⁺ and K⁺ ions against their gradients, energy will be required and this energy is supplied by ATP.

An ATP molecule which floats inside the cell, binds to the sodium-potassium pump and transfer some energy to it.

For example, if in the nerve cells, this pump stops working, Na⁺ will be accumulated within the cell and intracellular K⁺ falls. This may cause depolarization of the resting membrane potential.