The plasma membrane prevents all potassium ions from leaking out but allows all sodium ions to cross into the cell from the extracellular fluid. true / false.

FALSE

Explanation:

The plasma membrane has both Na –K channels across it walls. They are membrane transport proteins which hydrolyse ATP s for the active transport  mechanisms  for   transport of sodium and potassium ions across the  plasma membranes .

Naturally,there are more potassium ion channels than sodium channels in plasma membrane; potassium is also extracellular while sodium is extracellular

Therefore ,when  some potassium ions diffused into the Axoplasm,  from the extracellular medium;;some potassium  ions still move out BACK  into  the extracellular environments. Not all potassium are restricted from leaving .

This leakage occurs because of more available potassium ions channels  than sodium ions, and higher number of  available  potassium ions

Thus the answer is FALSE

the ratio of diffusion is 3 sodium  out to 2 potassium in