What does the Golgi apparatus primarily do in a cell?

The Golgi apparatus plays a crucial role in the cell as the primary site for modifying and packaging newly synthesized proteins. After proteins are made in the rough endoplasmic reticulum, they are transported to the Golgi apparatus where they undergo processing. This can include the addition of carbohydrate groups (glycosylation), phosphate groups (phosphorylation), and other types of modifications that are essential for the proteins to function properly.

Once the proteins have been modified, the Golgi apparatus sorts and packages them into vesicles. These vesicles can then transport the proteins to their final destinations, either within the cell or to the cell membrane for secretion outside the cell. The ability of the Golgi apparatus to efficiently modify and sort proteins is vital for maintaining cellular function and communication.