Facilitated diffusion

Facilitated diffusion is a type of passive transport that allows substances to cross cell membranes with the assistance of special transport proteins. This process is used by molecules that cannot diffuse rapidly through cell membranes, even when there is a concentration gradient across the membrane.

Overview

Facilitated diffusion is a type of passive transport that does not require the input of cellular energy. Instead, it relies on the concentration gradient created by each molecule. This means that molecules will move from an area of high concentration to an area of low concentration until equilibrium is reached.

Mechanism

The process of facilitated diffusion requires a specific transport protein. These proteins are embedded in the cell membrane and have a specific shape that allows only certain molecules to bind to them. When a molecule binds to the transport protein, it causes a change in the protein's shape, allowing the molecule to be transported across the membrane.

Types of Transport Proteins

There are two main types of transport proteins involved in facilitated diffusion: channel proteins and carrier proteins. Channel proteins form a pore in the cell membrane that allows molecules to pass through. Carrier proteins, on the other hand, bind to the molecule and change shape to carry the molecule across the membrane.

Role in the Body

Facilitated diffusion plays a crucial role in the body. It is responsible for the transport of necessary molecules such as glucose and amino acids across cell membranes. Without facilitated diffusion, cells would not be able to get the nutrients they need to function properly.

See Also

• Active transport
• Passive transport
• Cell membrane
• Transport protein
• Channel protein
• Carrier protein

Facilitated_diffusion

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  Scheme of facilitated diffusion in cell membrane
• Facilitated diffusion process
  Facilitated diffusion process
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  Illustration of facilitated diffusion