| facilitated diffusion | <physiology> A process by which substances are conveyed across cell membranes faster than would be possible by diffusion alone. This is generally achieved by proteins that provide a hydrophilic environment for polar molecules throughout their passage through the plasma membrane, acting as either shuttles or pores. See: symport, antiport, uniport. (18 Nov 1997) |
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| facilitated transport | The protein-mediated transport of a compound across a biomembrane that is not ion-driven; a saturable transport system. Synonym: passive transport. (05 Mar 2000) |