Mechanism and Selectivity of Facilitated Diffusion: Insights into Cellular Transport Proteins

Facilitated diffusion

Movement of specific molecules across cell membranes through protein channels

Facilitated diffusion is a type of passive transport in which molecules, ions or other small molecules are transported across the cell membrane from an area of high concentration to an area of low concentration with the help of transport proteins. Unlike simple diffusion, facilitated diffusion requires the presence of specific transport proteins embedded in the cell membrane to facilitate the movement of molecules across the membrane.

These transport proteins can be either channel proteins or carrier proteins. Channel proteins form pores in the cell membrane that allow certain ions or molecules to pass through. Carrier proteins, on the other hand, bind to a specific molecule and then undergo a conformational change that moves the molecule across the membrane.

Facilitated diffusion is a highly selective process, meaning that only certain molecules can pass through the transport proteins. Additionally, the rate of facilitated diffusion is limited by the number of available transport proteins and the rate at which they can transport molecules across the membrane.

Examples of molecules that are transported by facilitated diffusion include glucose, amino acids, and certain ions such as calcium, potassium and sodium.

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