Isotonic

Definition

In the context of cell membrane and cellular activities, isotonic describes a solution having the same solute concentration as another solution, thus not causing any net movement of water across the cell membrane. When cells are in an isotonic solution, there is no change in their volume due to water balance.

Related terms

Hypertonic: A hypertonic solution has a higher solute concentration than another solution, leading to water exiting cells placed in such a solution, potentially causing them to shrink.

Hypotonic: A hypotonic solution has a lower solute concentration than another solution, leading to water entering cells placed in such a solution, potentially causing them to swell and burst.

Osmosis: The process by which molecules of a solvent tend to pass through a semipermeable membrane from a less concentrated solution into a more concentrated one, thus equalizing the concentrations on each side of the membrane