4.3 osmosis

• osmosis is: the passage of water from a region where it has a higher water potential to a region where it has a lower water potential through a selectively permeable membrane
• water potential is measured in units of pressure
• water pressure is the pressure created by water molecules
• pure water is said to have a water potential of zero
• water will move from a region of higher water potential to an area of lower water potential
• when a dynamic equilibrium has been reached, there is no net movement of water
• if you put a cell in a solution with a higher water potential than the cell, the cell will swell and burst
• if you put a cell in a solution with a lower water potential than the cell, the cell will shrink