Osmosis

Osmosis

Osmosis is the diffusion of water from a dilute solution to a concentrated solution through a partially permeable membrane, such as the cell membrane.
Cells can be placed in solutions with different relative concentrations.
- Isotonic: concentration inside the cell is the same as the concentration of the solution. No net movement of water.
- Hypertonic: concentration of the solution is higher than the concentration inside the cell.
- Hypotonic: concentration of the solution is lower than the concentration inside the cell.
The water uptake rate in grams/hour is equal to the change in mass divided by the time in minutes.

Solution

Animal cell

Plant cell

Hypertonic (e.g. salty brine)

Shrunken/shrivelled

Flaccid → plasmolysed

Hypotonic (e.g. pure water)

Swell and burst

Turgid

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