Transportsubstans

Transportsubstans, or transport substances, is a term used in physiology and biochemistry to describe substances that participate in moving other molecules, ions, or particles within a living organism. The concept covers solvents, carrier molecules, and complexes that enable distribution, delivery, and clearance of materials through fluids and across membranes.

Classification. Transportsubstans can be grouped by function: solvents such as water; carrier or binding proteins that shuttle solutes in blood (albumin, transferrin, transthyretin); membrane transport proteins that facilitate movement of ions and small molecules (such as glucose transporters); lipoproteins that carry lipids; and vesicles involved in endo- and exocytosis. Some substances act as ligands or cofactors that aid solubility and stability during transport.

Mechanisms. Transport can occur by diffusion (passive and facilitated), active transport requiring energy, or vesicular processes. The mechanism depends on the substance’s properties and the physiological context.

Examples. Water as the universal solvent; oxygen and carbon dioxide bound to respiratory carriers; iron transported by transferrin; lipids carried by lipoproteins; glucose moved by GLUT transporters; calcium bound to intracellular proteins for storage and signaling; drugs and hormones often rely on carrier proteins for solubility and distribution.

Clinical and research relevance. Alterations in transportsubstans function contribute to disease, such as anemia from impaired iron transport or cardiovascular disease linked to lipoprotein transport. The concept underpins physiology, pharmacology, and drug delivery studies.

See also. Carrier proteins, membrane transport, endocytosis, diffusion.