verifiedCite
While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions.
Select Citation Style

What is the rough endoplasmic reticulum?

The rough endoplasmic reticulum, or RER, is a series of connected, flattened membrane sacs inside the cytoplasm of eukaryotic cells. It has a central role in making proteins. Its outer surface is covered with ribosomes, which are protein-synthesizing particles and give the RER its rough appearance. The RER is found in both plant and animal cells and is usually located near the nucleus.