What is the Origin of Carrier Transport?

The term originates from cellular biology and membrane physiology, combining "carrier" (a protein that binds and moves a substance) and "transport" (the act of moving across a barrier). It describes a fundamental principle of membrane dynamics and permeability control.

What is the Mechanism of Carrier Transport?

The process operates by the carrier protein binding to the substrate molecule on one side of the membrane, undergoing a conformational change, and then releasing the molecule on the opposite side. This can be either passive transport, following a concentration gradient, or active transport, which requires ATP to move substances against their gradient. Steroid hormones often utilize carrier proteins like Sex Hormone-Binding Globulin (SHBG) in the bloodstream, which is a form of extracellular carrier transport.

Carrier Transport ∞ Area

Carrier Transport

Meaning

Carrier transport is a crucial physiological process involving specialized protein molecules embedded within cell membranes that facilitate the movement of specific substances across the lipid bilayer. This mechanism is essential for regulating the intracellular concentration of nutrients, ions, and hormones, many of which cannot pass through the membrane unaided. It represents a controlled and often energy-dependent method of molecular delivery into the cell.