What organelle is primarily responsible for distributing proteins within the cell?

The Golgi apparatus is considered the primary organelle responsible for modifying, sorting, and distributing proteins within the cell. After proteins are synthesized on ribosomes, they are transported to the endoplasmic reticulum, where they undergo initial folding and modification. From the endoplasmic reticulum, the proteins are sent to the Golgi apparatus.

In the Golgi apparatus, these proteins are further processed, which may involve additional modifications, such as glycosylation (adding sugar molecules) or phosphorylation. Once processed, the Golgi apparatus sorts the proteins and packages them into vesicles that will transport them to their intended destinations. This may involve sending them to various parts of the cell, such as the plasma membrane, lysosomes, or for secretion outside of the cell. The Golgi apparatus essentially acts as a distribution center, ensuring that proteins reach the right location and are in the correct form needed for their function.