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active transport

   Also found in: Medical, Legal, Financial, Encyclopedia, Wikipedia, Hutchinson 0.05 sec.
active transport
n.
The movement of a chemical substance through a gradient of concentration or electrical potential in the direction opposite to normal diffusion, requiring the expenditure of energy: active transport across a cell membrane.

active transport
n
(Life Sciences & Allied Applications / Biochemistry) Biochem Physiol a process by which molecules are enabled to pass across a membrane from a region in which they are in a low concentration to one of high concentration; this requires the expenditure of energy in metabolism and is assisted by carrier proteins, commonly referred to as pumps

active transport
The movement of ions or molecules across a cell membrane in the direction opposite that of diffusion, that is, from an area of lower concentration to one of higher concentration. Active transport requires the assistance of a type of protein called a carrier protein, using energy supplied by ATP.
ThesaurusLegend:  Synonyms Related Words Antonyms
Noun1.active transport - transport of a substance (as a protein or drug) across a cell membrane against the concentration gradient; requires an expenditure of energy
drug - a substance that is used as a medicine or narcotic
transport - an exchange of molecules (and their kinetic energy and momentum) across the boundary between adjacent layers of a fluid or across cell membranes


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? Mentioned in ? References in periodicals archive
 
This finding was consistent with an active transport mechanism across the placenta.
Others have suggested that nitrate or the reduced form (nitrite) may pass to the fetus through a system of active transport similar to that of iodide, and fetal nitrate plasma levels may exceed that of the mother (Hartman 1982).
Interestingly, from a separate questionnaire sent home for parents to complete, the majority of parents (77%) stated they either walked or cycled to school themselves as 10-year-olds, indicating a substantial decrease in active transport in only one generation.
 
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