Passive Transport: Simple Diffusion vs Facilitated Transport Mechanisms

Distinguish between simple diffusion and facilitated transport.

Simple diffusion: moves down the concentration gradient (example nonpolar molecules can do this)Facilitated transport: materials move down concentration gradient with the help of proteins such as channels or transporters

Simple diffusion and facilitated transport are both mechanisms of passive transport that move substances across a cell membrane without the input of energy. However, they differ in how they transport molecules across the membrane.

Simple diffusion is the movement of molecules across a membrane from an area of high concentration to an area of low concentration. It does not require any carrier proteins or energy input. In simple diffusion, small, uncharged molecules such as oxygen and carbon dioxide can diffuse freely across the cell membrane, while larger or charged molecules may require the assistance of transport proteins.

Facilitated transport, on the other hand, involves the use of protein channels or carriers to move molecules across the membrane. Unlike simple diffusion, facilitated transport is selective and can move larger or charged molecules such as glucose or amino acids across the membrane. It also moves molecules from an area of high concentration to an area of low concentration but it requires the presence of specific transport proteins to facilitate the movement of molecules.

Overall, the key difference between simple diffusion and facilitated transport is the involvement of transport proteins. While simple diffusion does not require transport proteins, facilitated transport relies on these proteins to move molecules across the membrane.

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