Which organelle works with the Rough ER to modify proteins that are exported from the cell?

• A. Golgi apparatus
• B. Lysosome
• C. Nucleus
• D. Peroxisome

Answer: (A)

Proteins destined for export are synthesized on ribosomes attached to the rough endoplasmic reticulum and then sent to the Golgi apparatus for finishing touches. In the Golgi, these proteins are further modified—carbohydrate groups are added or trimmed (glycosylation), structures are properly folded, and sometimes pieces are cleaved—before they are packaged into secretory vesicles that ferry them to the cell surface or other destinations. This cooperation between the rough ER and Golgi ensures that exported proteins are correctly processed and sorted for their ultimate path. The other organelles listed don’t perform this post-translational modification and trafficking role: the lysosome degrades materials, the nucleus houses genetic material, and peroxisomes handle lipid metabolism and detoxification.