Morris, Biology for the AP Course 1e - Mod 11

solute

A dissolved molecule such as the ions, amino acids, and sugars often found in a solvent such as water.

molarity

The amount of a solute in a volume of solution, expressed as moles of a solute per liter of solution. Also called molar concentration.

osmosis

The net movement of a solvent, such as water, across a
selectively permeable membrane toward the side of higher solute concentration.

water potential

A parameter that combines all the physical and chemical factors that influence the movement of water, such as pressure, osmosis, and gravity; water moves from regions of higher water potential to regions of lower water potential.

osmotic pressure

The pressure needed to prevent water from moving
from one solution into another by osmosis.

tonicity

A measure of osmotic pressure; the higher the osmotic pressure, the higher the tonicity.

hypertonic

Describes a solution having a higher solute concentration (lower water potential) than another solution.

hypotonic

Describes a solution having a lower solute concentration (higher water potential) than another solution.

isotonic

Describes a solution having the same solute concentration (same water potential) as another solution.

contractile vacuole

An organelle in some protists that actively takes up and expels water that enters the cell by osmosis.

pressure potential

The effect of pressure in the movement of water.

solute potential

The effect of solutes on the movement of water.

osmoregulation

The regulation of water and solute levels to control osmotic pressure.