Question: what is the important structural difference between rough endoplasmic reticulum (er) and smooth er?
Answer: Both the smooth and rough endoplasmic reticulum help in the production and storage of proteins The main difference is that one contains ribosomes on it and the other does not. The rough endoplasmic reticulum (RER) has ribosomes on its surface. This is what give the RER a "rough" appearance.