Which mechanism describes facilitated diffusion?

Facilitated diffusion is a specific type of passive transport that involves the movement of solutes across a cell membrane through a protein channel. This mechanism is characterized by solute binding to a specific receptor or transport protein in the membrane. When the solute binds to the receptor, it induces a conformational change in the protein, enabling the solute to pass through the membrane. This process is crucial for transporting substances that cannot readily diffuse through the lipid bilayer, such as ions and polar molecules, because of their size or solubility properties.

The dynamics of facilitated diffusion do not require energy in the form of ATP, as it relies on the concentration gradient of the solute—moving from an area of higher concentration to one of lower concentration. This underlines the significance of the conformational change caused by the binding of the solute to the receptor, which is central to the function of facilitated diffusion.