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
energy-expanding process in which cells transport materials across the cell membrane against a concentration gradient.
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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 - ENERGY TO TRANSPORT
Active transport describes what happens when a cell uses energy to transport something. We're not talking about phagocytosis (cell eating) or pinocytosis (cell drinking) in this section.
active transport of molecules and ions
nerve impulses
maintenance of cell volume by osmosis
adding phosphate groups (phosphorylation) to many different proteins, e.g., to alter their activity in cell signaling.
muscle contraction ...
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 of Amino Acids
The active transport of amino acids is also mediated by Na+ cotransport.
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Active transport The transport of an ion or a molecule against a concentration gradient, where DG for the transported species is positive; the process must be coupled to an input of free energy from a source such as ATP, ...
[edit] Active transport
Primary active transport
Transport proteins are also used in active transport, which by definition does require an energy input.
active transport
The Southwest Environmental Health Sciences Center
The Biology Project
The University of Arizona
Monday, February 22, 1999
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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 ...
Active transport requires the cell to spend energy, usually in the form of ATP. Examples include transport of large molecules (non-lipid soluble) and the sodium-potassium pump.
Many of the proteins play a role in the selective transport of certain substances across the phospholipid bilayer, either acting as channels or active transport molecules.
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, Membrane, Protein, Cell, Molecule
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