Exam 1 Review:  Chapter 3 - Osmosis

simple diffusion - The spontaneous movement of molecules or other particles in solution, owing to their random thermal motion, to reach a uniform concentration throughout the solvent, a process requiring no addition of energy to the system.

concentration gradient - The relationship in mass/unit volume, the graduated difference in concentration of a solute, per unit distance through a solution or on opposite sides of a semipermeable membrane; the kinetic energy of individual molecules and their random paths in motion produce movements in which the net effect is for substances to diffuse in the direction of the concentration gradient until an equilibrium concentration is reached, unless that movement is obstructed or some other force resists the movement.

net diffusion - The rate of dispersion per unit of time as molecules of solute scatter through a solution or across a semipermeable membrane; at equilibrium, solute concentration is the same throughout the solution or on both sides of the membrane and net diffusion is zero.

equilibrium - A condition in which all acting influences are canceled by others, resulting in a stable, balanced, or unchanging system, e.g., the state of a chemical reaction in which its forward and reverse reactions occur at equal rates so that the concentration of the reactants and products does not change with time.

osmosis - Passive diffusion of water (and other aqueous solutions) through a semipermeable membrane from a solution with a low solute concentration to a solution with a higher solute concentration until there is an equal concentration of fluid on both sides of the membrane; this movement of water requires only the inherent kinetic energy of the water molecules themselves; this type of water movement may create a significant hydrostatic force.

osmotic pressure - The hydrostatic force which can be generated when water moves across a selectively permeable membrane, following its concentration gradient, to a fluid compartment which is hypertonic to the compartment on the other side of the membrane. This force contributes to the overall size and shape of many cells.

tonicity - The comparative strength of a solution in terms of its osmotic pressure.

isotonic - An adjective describing any two solutions which have the same or equal osmotic pressure.

hypertonic - An adjective describing any solution which has the greater osmotic pressure of two solutions being compared.

hypotonic - An adjective describing any solution which has the lesser osmotic pressure of two solutions being compared.

hemolysis - The destruction or dissolution of red blood cells, with subsequent release of hemoglobin.

crenation - A process resulting from osmosis in which red blood cells, in a hypertonic solution, undergo shrinkage and acquire a notched or scalloped surface.

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