Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025
Definition
Osmolarity is the concentration of solute particles in a solution, expressed as osmoles per liter. It plays a crucial role in determining the movement of water across plasma membranes through passive transport mechanisms like osmosis.
5 Must Know Facts For Your Next Test
Osmolarity affects the direction and rate of osmosis across cell membranes.
A solution with higher osmolarity than another is hyperosmotic to it.
In passive transport, water moves from an area of lower osmolarity to an area of higher osmolarity.
Isotonic solutions have equal osmolarities, resulting in no net movement of water.
Measuring osmolarity is essential for understanding cell volume regulation and maintaining homeostasis.
Review Questions
Related terms
Osmosis: The passive transport process where water molecules move across a semipermeable membrane from low to high solute concentration.
Hypertonic: A solution with a higher concentration of solutes compared to another solution, leading to potential cell shrinkage due to water loss.
Hypotonic: A solution with a lower concentration of solutes compared to another solution, potentially causing cells to swell due to water intake.