Isotonic

Definition

Isotonic refers to a situation where two solutions have the same solute concentration, resulting in no net movement of water across a semipermeable membrane. It is crucial in maintaining cell stability and function by preventing excessive water influx or efflux.

5 Must Know Facts For Your Next Test

1. In an isotonic environment, animal cells maintain their normal shape and function because there is no net water movement across the plasma membrane.
2. Isotonic solutions are used in medical treatments, such as intravenous fluids, to ensure that cells do not shrink or swell.
3. Plant cells in an isotonic solution are flaccid because turgor pressure is not generated against the cell wall, unlike in hypotonic environments.
4. The balance achieved by isotonic conditions helps maintain homeostasis within tissues and organs.
5. A common example of an isotonic solution is 0.9% saline (sodium chloride) which matches the osmolarity of human blood.

Review Questions

• What happens to animal cells when placed in an isotonic environment?
• Why are isotonic solutions important for intravenous treatments?
• How do plant cells behave differently in isotonic solutions compared to hypotonic solutions?

Related terms

Hypertonic: A solution with a higher solute concentration than another solution, causing water to move out of the cell and leading to cell shrinkage.

Hypotonic: A solution with a lower solute concentration than another solution, causing water to move into the cell and potentially leading to cell swelling or bursting.

Osmosis: The passive transport process by which water molecules move across a semipermeable membrane from a region of lower solute concentration to higher solute concentration.