transport

The movement or transference of biochemical substances in biologic systems. [L. transporto, to carry over, fr. trans- + porto, to carry]

- active t. the passage of ions or molecules across a cell membrane, not by passive diffusion but by an energy-consuming process at the expense of catabolic processes proceeding within the cell; in active t., movement takes place against an electrochemical gradient.

- axoplasmic t. t. by way of flow of axoplasm toward cell soma (retrograde) or toward axon terminal (anterograde).

- facilitated t. the protein-mediated t. of a compound across a biomembrane that is not ion-driven; a saturable t. system. SYN: passive t..

- hydrogen t. the transfer of hydrogen from one metabolite (hydrogen donor) to another (hydrogen acceptor) through the action of an enzyme system; the donor is thus oxidized and the acceptor reduced.

- paracellular t. solvent movement across an epithelial cell layer through the tight junctions between cells. Cf.:transcellular t..

- passive t. SYN: facilitated t..

- transcellular t. solute movement across an epithelial cell layer through the cells. Cf.:paracellular t..

- vesicular t. SYN: transcytosis.

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trans·port tran(t)s-'pō(ə)rt, -'pȯ(ə)rt, 'tran(t)s-. vt to transfer or convey from one place to another <mechanisms of \transporting ions across a living membrane>

trans·port 'tran(t)s-.pō(ə)rt, -.pȯ(ə)rt n an act or process of transporting specif ACTIVE TRANSPORT

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trans·port (transґport) [L. transportare to carry across] the movement of substances in biological systems, particularly into and out of cells and across epithelial layers.