Question

Define the ionic steady state equaliibrium. Describe it (permeabilities, actual or relative ion concentrations) and what three cell activities create and maintain it?

Answer 1

Cells maintain different internal and external concentrtaion of various ionic species .These ions constantly move in and out of the cell but maintain a resting membrane potencial which is mostly negative .This state of the membrane is called steady ionic state .

The cell membrane serves as both as diffusion membrane and insulating membrane for ions .

Ions move in and out of the cell via ion channels which allow the movement of ions down the concentration gradient .whereas ion transport protein pump allows the movement of ions with the help of ATP energy derived from various cellular activities like glycolysis and kreb cycle and respiratory chain .

Ions move across the membrane via the following three modes

-Gated channels - open and close depending upon concentration of ions in the cell

-Na+/K+ pump -Move ions across the cell membrane against their concentrtaion gradient

-leak channels - move ions across the membrane down their concentration gradients