1. Passive Transport - Osmosis
The movement of water across a semi-permeable membrane from [high] to [low]
Osmosis is a special type of diffusion for water
Typically, membranes involved in osmosis are impermeable to solute
Aquaporins in the cell membrane allow water through
Cells can be 1 of 3 things:
Hypertonic
Hypotonic
Isotonic

2. Passive Transport - Osmosis
HYPERTONIC:
More solute concentration in an area
- Water moves into the cell (expands, and possibly bursts)
HYPOTONIC:
Less solute concentration in an area
- Water moves out of the cell (shrinks).

3. Passive Transport - Osmosis
ISOTONIC:
Same concentration of solute inside and outside of a cell
Cell will stay the same size due to water moving in and out in equal amounts.
Example:
What is this cell (hyper, hypo, isotonic)? Hypotonic
What direction would the solvent move? Out of the cell
What direction would the solute move IF the membrane was permeable to the solute? Solute would go into cell
What state would the cell eventually reach? Equilibrium (Dynamic)

4. Extra Example Is the cell hypertonic, hypotonic, or isotonic?
Is the outside solution hypertonic, hypotonic, or isotonic?
In which direction will the water move?
Solution
70% H2O
30% Sugar
Cell
75% H2O
25% Sugar