Isotonic solution
The membrane is permeable to water
Water potentialEqual on both sides
Cell volumeStable
Biological termDynamic equilibrium
AP Biology · Cell membranes
Cells in changing tonicity
Compare how animal and plant cells respond when the surrounding solution changes.
Check your prediction
A red blood cell is placed in distilled water. What happens?
Choose an answer, then use the model to check your reasoning.
Isotonic solution
The cell wall resists expansion
Central vacuoleModerate volume
Turgor pressureLow
Biological termFlaccid
Check your prediction
A plant cell is placed in fresh water. Why does it become firm without bursting?
Choose an answer, then compare the wall and membrane in the model.