What are vesicles primarily composed of?

Vesicles are primarily composed of sacs made of membrane, which is correct. These membrane-bound structures are essential for various cellular processes, including the transport of materials within and outside of the cell.

The membrane of vesicles is typically made up of a lipid bilayer, similar to the cell membrane, which allows them to encapsulate substances and maintain a distinct internal environment. This composition enables vesicles to carry proteins, lipids, and other molecules to their specific destinations within the cell or for secretion outside the cell.

Understanding the structure of vesicles as membrane-bound sacs helps underscore their role in cellular transport and communication, highlighting the importance of their composition in maintaining cellular function.