Which organelle is primarily responsible for modifying, sorting, and packaging proteins for secretion?

• A. Golgi apparatus
• B. Ribosome
• C. Lysosome
• D. Endoplasmic reticulum

Answer: (A)

The Golgi apparatus handles the post‑translational processing, sorting, and packaging of proteins for secretion. After proteins are made in the rough endoplasmic reticulum, they arrive at the Golgi, where enzymes add carbohydrate groups and other modifications. The Golgi then sorts these proteins to their correct destinations and packages them into secretory vesicles that fuse with the plasma membrane to release their contents outside the cell. The rough ER is primarily involved in protein synthesis and initial folding, while ribosomes themselves build the proteins, not modify or package them. Lysosomes are specialized for digestion inside the cell.