Active transport

Active transport Main article: Active transport Typically moves molecules against their electrochemical gradient, a process that would be entropically unfavorable were it not stoichiometrically coupled with the hydrolysis of ATP. Full article ...

active transport energy-expanding process in which cells transport materials across the cell membrane against a concentration gradient. Source: User Submission ...

Active transport is important so that substances can move in and out of a cell across the selectively permeable cell membrane against a concentration gradient. Compare: passive transport, diffusion. See also: concentration gradient.

Active transport is the mediated transport of biochemicals, and other atomic/molecular substances, across membranes. Unlike passive transport, this process requires chemical energy.

Active transport is the pumping of molecules or ions through a membrane against their concentration gradient. It requires: a transmembrane protein (usually a complex of them) called a transporter and energy. The source of this energy is ATP.

Active transport is like a water pump; it uses energy to pump water uphill where a siphon cannot. Facilitated diffusion (see above) is like a siphon in that additional energy is not required but it can only allow movement downhill.

active transport Transport of molecules against a concentration gradient (from regions of low concentration to regions of high concentration) with the aid of proteins in the cell membrane and energy from ATP. PICTURE ...

active transport The movement of a substance across a biological membrane against its concentration or electrochemical gradient, with the help of energy input and specific transport proteins. adaptation ...

active transport A process that requires an expenditure of ATP energy to move molecules across a cell membrane; usually moved against the concentration gradient with the aid of specific transport proteins.

active transport - movement of a molecule across a membrane or other barrier driven by energy other than that stored in the concentration gradient or electrochemical gradient of the transported molecule ...

The active transport of potassium and sodium ions into and out of the cell, respectively, is accomplished by a number of sodium-potassium pumps scattered across the cell membrane.

active site The region of an enzyme that binds a substrate molecule and catalytically transforms it, usually a small portion of the total enzyme molecule active transport Energy-requiring transport of a solute across a membrane in the direction of ...

This is done by a selective process involving active transport and the utilization of a lot of ATP. Nutrients are reabsorbed by the cells lining the nephron and water is reabsorbed as needed. Waste products such as urea are not reabsorbed.

See also: Trans, Protein, Molecule, Cell, Cells