Which structure is a system of membranes that modifies and packages proteins for export by the cell?

The Golgi apparatus is a system of membranes responsible for modifying, sorting, and packaging proteins for secretion or delivery to other organelles. Once proteins are synthesized in the endoplasmic reticulum, they are transported to the Golgi apparatus in vesicles. Within the Golgi, enzymes attach carbohydrates and lipids to proteins, which is crucial for their proper functioning and destination. After processing, the Golgi apparatus then packages these modified proteins into vesicles, which can fuse with the cell membrane to release their contents outside the cell or deliver them to other locations within the cell. This role is essential for cell communication and overall function, highlighting the importance of the Golgi apparatus in the cell's secretory pathway.