Both rough endoplasmic reticulum (Rough ER) and smooth endoplasmic reticulum (Smooth ER) are types of endoplasmic reticulum (ER) found in eukaryotic cells, but they have distinct structures and functions:
-
Rough ER:
- Studded with ribosomes on its cytoplasmic surface, giving it a "rough" appearance.
- Primarily involved in the synthesis and processing of proteins, particularly those intended for secretion, incorporation into the cell membrane, or for use in lysosomes.
- The ribosomes on Rough ER translate mRNA into polypeptide chains, which then enter the lumen of the ER for folding and modification.
-
Smooth ER:
- Lacks ribosomes, resulting in a "smooth" appearance.
- Functions in the synthesis of lipids, metabolism of carbohydrates, detoxification of drugs and poisons, and storage of calcium ions.
- It is also involved in the production of steroid hormones in certain cells.
In summary, the key difference is that Rough ER is involved in protein synthesis due to the presence of ribosomes, while Smooth ER is involved in lipid synthesis and other metabolic processes.