How does facilitated transport differ from simple diffusion?

Facilitated transport is a specific type of passive transport that involves the movement of molecules across a cell membrane through the assistance of specialized proteins known as carrier proteins or channel proteins. These proteins help to facilitate the passage of larger or polar molecules that cannot readily diffuse through the lipid bilayer of the membrane due to their size or polarity.

In facilitated transport, the molecules still move down their concentration gradient, which means they move from an area of higher concentration to an area of lower concentration without the expenditure of cellular energy (ATP). This sets it apart from active transport, where energy is required to move substances against their concentration gradient.

The use of carrier proteins is crucial in this process; they change shape to move the bound substances across the membrane, thereby allowing substances like glucose or ions to enter or exit the cell more efficiently than they would through simple diffusion alone. Understanding this mechanism is pivotal for comprehending how cells maintain homeostasis and transport necessary nutrients efficiently.