transport of a substance (as a protein or drug) across a cell membrane against the concentration gradient a difference in the concentration of a substance across a distance pathological breakdown of cells by the destruction of their outer membrane the act of dispersing or diffusing something process by which a cell takes material into the cell by infolding of the cell membrane a state of balance process by which a cell RELEASES large amounts of material movement of specific molecules across cell membranes through protein channels  (of a solution) having a higher osmotic pressure than a comparison solution  (of a solution) having a lower osmotic pressure than a comparison solution diffusion of molecules through a semipermeable membrane from a place of higher concentration to a place of lower concentration until the concentration on both sides is equal transport of a substance across a cell membrane by diffusion allowing (especially liquids) to pass or diffuse through when a cell is in a hypertonic environment, the cell will lose water to its surroundings, shrink, and its plasma membrane will pull away from the wall