Solute
Substance which is dissolved in solvent
Solvent
Liquid in which solute is dissolved
Concentration gradient
Actual difference in concentration a dissolved substance in a solution between a region of high density and one of lower density
Selectively permeable
Cell membrane that allows certain molecules or ions to pass through it by means of active or passive transport
Isotonic
When a solution is in equilibrium
Hypertonic
When there is too much of a solid in a solution
Hypotonic
When there are not enough, or no solids in a solution