1. Tonicity
Tonicity is a measure of the osmotic pressure (as defined by the water potential of the two solutions) of two solutions separated by a semipermeable membrane.

2. Reminder
Concentration- The amount of solute per unit of solvent.
Osmosis is the flow of water down the concentration gradient (from an area of high concentration to an area of low concentration)
Water never stops moving, even when equilibrium has been reached.

3. Isotonic
The net movement of water across the semipermeable membrane is equal.
The amount of water entering a cell is the same as the amount leaving the cell
Isotonic Plant cells are Flaccid.
Water never stops moving, even when equilibrium has been reached.

4. Hypotonic
There is more substances than water inside the cell. The concentration will try to even out.
Water will enter the cell. This causes the cell to swell (get larger) until it may burst.
Hypotonic Plant cells are Turgid.
The Process of swelling animal cells is called hemolysis
PUTTING A CELL IN PLAIN WATER

5. Hypertonic
There is less substances than water inside the cell. The concentration will try to even out.
Water will leave the cell. This causes the cell to shrink (get smaller)
Hypertonic Plant cells are Plasmolyzed.
The Process of shrinking animals cells is called crenation
PUTTING A CELL IN SALT WATER

6. Tonicity Tonicity of Solution Water (outside of cell) Net Movement
Concentration of
Solute (outside of cell)
Water (outside of cell)
Net Movement
End Product
Isotonic
Same as cell
None
Hypotonic
Less than cell
More than cell
Cell gains water
Swells, turgor pressure
Hypertonic
Cell loses water
Shrinks plasmolysis

7. Practice
hill.com/sites/ /student_view0/c hapter21/animation__hemolysis_and_crenati on.html
Lets watch a clip and answer questions about red blood cells in different solutions.