1. Tonicity Tonicity of two solutions separated by a semipermeable membrane, is the relative concentration of solutions that determine the direction and extent of diffusion.

3. 10% NaCl 90%H 2 O 10% NaCl 90%H 2 O NO NET MOVEMENT - cell stays the same

4. 10% NaCl 90%H 2 O 20% NaCl 80%H 2 O Water moves into the cell causing it to swell.

5. 15% NaCl 85%H 2 O 5% NaCl 95%H 2 O Water moves out of the cell causing it to shrink.

6. It can be a bit confusing… So we name the solution based on it’s relative concentration of solute to water (more or less solute than water?) However, it’s the water that will diffuse (osmosis) into or out of the cell where there is a greater need for water (where there’s more solute).