What is a primary function of the Golgi apparatus?

The Golgi apparatus plays a crucial role in the processing and management of proteins within the cell. Its primary function is to modify, sort, and package proteins that have been synthesized in the endoplasmic reticulum. Once the proteins are produced, they need to be fine-tuned, which often involves adding carbohydrate groups (glycosylation) or phosphate groups (phosphorylation) to become fully functional. After modification, the Golgi apparatus sorts these proteins based on their destinations—whether they are to be secreted outside the cell, sent to a lysosome, or incorporated into the cell membrane. This organelle essentially acts like a post office, ensuring that proteins are delivered to the correct locations where they are needed, which is vital for proper cellular function.