active transport

active transport

noun
the movement of ions or molecules across a cellular membrane from a lower to a higher concentration, requiring the consumption of energy.

Origin:
1960–65

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World English Dictionary
active transport
 
n
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

Collins English Dictionary - Complete & Unabridged 10th Edition
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American Heritage
Medical Dictionary

active transport n.
The passage of ions or molecules across a cell membrane against an electrochemical or concentration gradient, or against the normal direction of diffusion.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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American Heritage
Science Dictionary
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.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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