Question

what is the atomic level basis of the potassium channel ion selectivity? (human biology)

Answer 1

The potassium channels are trans-membranous proteins which help in transfer of potassium ions across a cell, thus resulting in change in the tonicity of the cell and maintain an electro-chemical gradient. However, it is highly important to note here that the funcitoning and selectivity of the potassium channels is dependent largely upon the sodium ion gradient across the cells as compared to the potassium ion gradients. Hence, the electro-chemical changes in the inward and outward sides of the cells would help in selective opening and functioning of the potassium channels across the cells.

Studies have shown, as in the neurons, that for every three sodium ions transported inside the cell, the change in the trans-membranous electro-chemical gradient pushes the cell to activate its potassium channels and release out two potassium ions across the cell. In this way, the potassium channels selectively bind to the potassium ions secondary to the atomic concentration and electro-chemical gradient of the sodium ions to maintain optimum functioning of the cells, such as transduction of nervous signal.