What is the main function of the Golgi apparatus?

The main function of the Golgi apparatus is to process, sort, and package proteins and lipids that have been synthesized in the endoplasmic reticulum (ER). Once proteins and lipids are produced in the rough and smooth ER, they are transported to the Golgi apparatus, which modifies them as necessary through processes such as glycosylation (adding carbohydrate groups) and packaging them into vesicles for transport to their final destinations, which could be within the cell or for secretion outside the cell. This organelle plays a critical role in ensuring that proteins are correctly modified and delivered, thus facilitating proper cellular function and communication. The Golgi apparatus acts as the cell's "shipping and receiving center," ensuring that materials are dispatched accurately based on the needs of the cell.