Osmosis

The passage of water from a region of high water potential to a region of lower water potential through a selctively permeable membrane.

• Cell-surface membranes are selectively permeable.
• Permeable to water molecules and few other small molecules.
• Not large molecules.

• Water potential is represented by psi (insert picture of mini trident looking symbol).
• Measured in kilopascals (Kpa).
• Water potential is the pressure created by water molecules.
• 25 degrees C and 100 Kpa, pure water has a water potential of 0 .
• The water potential of a solution must always be a negative value .
• The highest water potential is 0.