Topic 2A.3 Osmosis

water potential

a measure of the potential for water to move out of a solution by osmosis

osmotic concentration

a measure of the concentration of the solutes in a solution that have an osmotic effect

isotonic solution

a solution in which the osmotic concentration of the solutes is the same as that in the cells

hypotonic solution

a solution in which the osmotic concentration of solutes is lower than that in the cell contents

hypertonic solution

a solution in which the osmotic concentration of solutes is higher than that in the cell contents

hydrostatic pressure

the pressure exerted by a fluid in an equilibrium

turgor

the state of a plant cell when the solute potential causing water to be moved into the cell by osmosis is balanced by the force of the cell wall pressing on the protoplasm

incipient plasmolysis

the point at which so much water is moved out of the cell by osmosis that turgor is lost, and the cell membrane begins to pull away from the cell wall as the protoplasm shrinks

plasmolysis

the situation when a plant cell is placed in hypertonic solution when so much water leaves the cell by osmosis that the vacuole is reduced, and the protoplasm is concentrated and shrinks away from the cell walls