Which organelle is responsible for protein modification and sorting?

The Golgi apparatus is responsible for the modification, sorting, and packaging of proteins and lipids that have been synthesized in the cell. Once proteins are made in the ribosomes and initially processed in the endoplasmic reticulum (ER), they are transported to the Golgi apparatus. Here, they undergo further modifications, such as glycosylation (addition of carbohydrates) or phosphorylation.

After these modifications, the Golgi apparatus sorts the proteins and prepares them for transport to their final destinations, whether inside the cell or for secretion outside the cell. This process is crucial for ensuring that proteins reach where they are needed and are functional, playing a critical role in cellular organization and functioning.

In contrast, the lysosome's role is primarily in digestion and recycling of cellular waste, while ribosomes are associated with protein synthesis. The endoplasmic reticulum is involved in initial protein and lipid synthesis rather than the final sorting and modification processes that the Golgi apparatus is known for.