Diffusion, Osmosis, and Active Transport

Diffusion

Movement of molecules from an area of higher concentration to an area of lower concentration.

Dynamic Equilibrium

Result of diffusion where there is continuous movement of particles but no overall change in concentration

Facilitated Diffusion

Movement of specific molecules across cell membranes through protein channels

Osmosis

Diffusion of water through a selectively permeable membrane

Isotonic Solution

A solution in which the concentration of solutes is essentially equal to that of the cell which resides in the solution

Hypotonic Solution

A solution in which the concentration of solutes is less than that of the cell that resides in the solution

Hypertonic Solution

A solution in which the concentration of solutes is greater than that of the cell that resides in the solution

Active Transport

Energy-requiring process that moves material across a cell membrane against a concentration difference

Endocytosis

Process by which a cell takes material into the cell by infolding of the cell membrane

Exocytosis

Process by which a cell releases large amounts of material