Biology / Unit 2 Bio 0349 short lesson, about 20 seconds
Osmolarity and Tonicity
Captions available
The idea
Osmolarity measures a solution's total solute concentration; tonicity describes how that osmolarity, compared to a cell's, moves water into or out of it.
In practice
A low-osmolarity solution holds more water relative to solute than a high-osmolarity one, so water moves toward the higher side.
Where people slip
Osmolarity counts dissolved particles, not suspended cells — a cell-crowded solution can still read lower.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
Builds on
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