Transport vesicle

Transport vesicles are small spheroidal structures that are used by cells to move molecules from one location to another. They are a key component of the cell's internal transport system, and are involved in processes such as protein trafficking, lipid transport, and endocytosis.

Structure and Composition

Transport vesicles are typically 30-100 nanometers in diameter and are composed of a lipid bilayer membrane. The lipid bilayer is similar in composition to the cell's own membrane, and serves to protect the contents of the vesicle from the surrounding cellular environment. Inside the vesicle, a variety of molecules can be found, including proteins, lipids, and RNA molecules.

Function

The primary function of transport vesicles is to move molecules from one part of the cell to another. This is accomplished through a process known as vesicle trafficking, in which vesicles bud off from one organelle, move through the cytoplasm, and then fuse with another organelle or the cell membrane. This allows the cell to selectively transport molecules to specific locations, and is essential for maintaining cellular homeostasis.

Transport vesicles are also involved in the process of endocytosis, in which the cell engulfs external materials and brings them into the cell. In this process, a portion of the cell membrane invaginates to form a vesicle, which then pinches off and moves into the cytoplasm.

Types of Transport Vesicles

There are several different types of transport vesicles, each with its own specific function. These include:

• Clathrin-coated vesicles: These vesicles are involved in the transport of proteins from the Golgi apparatus to the plasma membrane, as well as in endocytosis.
• COP-coated vesicles: These vesicles are involved in transport between the endoplasmic reticulum and the Golgi apparatus, as well as within the Golgi apparatus itself.
• SNARE-coated vesicles: These vesicles are involved in the fusion of vesicles with their target membranes.

See Also

• Endocytosis
• Exocytosis
• Vesicle trafficking
• Cell biology