Which structure is involved in the modification and packaging of proteins?

The Golgi apparatus plays a crucial role in the modification and packaging of proteins. After proteins are synthesized by ribosomes, they enter the endoplasmic reticulum, where initial folding and modification occur. Once synthesized and modified, these proteins are transported to the Golgi apparatus, where further modifications take place. The Golgi apparatus processes these proteins—such as adding carbohydrate groups or other modifications—and then packages them into vesicles for transport to their final destinations, which could include secretion outside the cell or delivery to specific organelles.

This function is essential for ensuring that proteins are properly prepared and formatted for their roles in the cell, as well as for regulating the timing and location of protein delivery. The other structures listed have different primary functions: the nucleus is involved in genetic information storage and expression, ribosomes are the sites of protein synthesis, and the endoplasmic reticulum assists in protein and lipid synthesis, but it is the Golgi apparatus that specializes in the final processing and distribution of proteins.