In eukaryotic cells, which organelle is primarily responsible for sorting and packaging proteins into vesicles for secretion or delivery to other destinations?

• A. Rough endoplasmic reticulum
• B. Mitochondrion
• C. Golgi apparatus
• D. Lysosome

Answer: (C)

Verified step by step guidance

1. Step 1: Understand the role of the Rough Endoplasmic Reticulum (RER). The RER is primarily involved in the synthesis of proteins, especially those destined for secretion or membrane insertion, but it does not sort or package these proteins.
2. Step 2: Consider the function of the Mitochondrion. Mitochondria are the powerhouses of the cell, generating ATP through cellular respiration, and are not involved in protein sorting or packaging.
3. Step 3: Examine the role of the Golgi apparatus. The Golgi apparatus receives proteins from the RER, modifies them if necessary, sorts them, and packages them into vesicles for transport to their final destinations, such as secretion outside the cell or delivery to lysosomes.
4. Step 4: Review the function of Lysosomes. Lysosomes contain digestive enzymes and are involved in breaking down cellular waste and macromolecules, not in sorting or packaging proteins for secretion.
5. Step 5: Conclude that the organelle responsible for sorting and packaging proteins into vesicles for secretion or delivery is the Golgi apparatus, based on its central role in processing and trafficking proteins after synthesis.