Final answer:
The rough endoplasmic reticulum is responsible for the synthesis and modification of proteins, with ribosomes on its surface aiding in protein production.
Step-by-step explanation:
The function of the rough endoplasmic reticulum (rough ER) is to synthesize and modify proteins that are typically destined for the cell membrane or for export from the cell. The surface of the rough ER is studded with ribosomes, which are responsible for protein synthesis.
Once proteins are synthesized, they may undergo glycosylation within the rough ER's channels before being transported to the Golgi apparatus for further processing and sorting. The smooth endoplasmic reticulum, which is distinct from the rough ER, is involved in lipid and hormone synthesis, detoxification processes, calcium ion storage, and metabolism of carbohydrates.