15 terms

BIOLOGY Cell Transport

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homeostasis
metabolic equilibrium actively maintained by several complex biological mechanisms that operate via the autonomic nervous system to offset disrupting changes; process by which organisms maintain a stable internal environment
concentration
the strength of a solution; the amount of solute dissolved in a solvent
diffusion
the process by which molecules move from an area of higher concentration to an area of lower concentration
osmosis
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
concentration gradient
a difference in the concentration of a substance across a distance
equilibrium
equality of distribution; state where there is no net movement of molecules
passive transport
the movement of substances across a cell membrane without the use of energy by the cell
active transport
energy-requiring process that moves material across a cell membrane against a concentration gradient
endocytosis
process by which a cell takes material into the cell by infolding of the cell membrane
exocytosis
the process by which a substance is released from the cell through a vesicle that transports the substance to the cell surface and then fuses with the membrane to release the substance
solute
the dissolved substance in a solution
solvent
a liquid substance capable of dissolving other substances
positive feedback loop
Situation in which a change in a certain direction provides information that causes a system to change further in the same direction.
negative feedback loop
A feedback loop that causes a system to change in the opposite direction from which it is moving
semipermeable membrane
a membrane (as a cell membrane) that allows some molecule to pass through but not others