Rough Endoplasmic Reticulum (RER)
1) It possesses ribosomes attached to its membrane.
2) It participates in the synthesis of enzymes and proteins.
3) Formed of cisternae and a few tubules
Smooth Endoplasmic Reticulum (SER)
1) It does not have ribosomes on its membrane.
2) Synthesises glycogen, lipids and steroids
3) Formed of vesicles and tubules