Endoplasmic reticulum (ER)
- Endoplasmic reticulum is a network or reticulum of tiny tubular structures scattered in the cytoplasm.
- ER divides the intracellular space into two distinct compartments, i.e., luminal (inside ER) and extra luminal (cytoplasm) compartments.
- The endoplasmic reticulum bearing ribosomes on their surface is called rough endoplasmic reticulum (RER), whereas in the absence of ribosomes they appear smooth and are called smooth endoplasmic reticulum (SER).
- RER is involved in protein synthesis and secretion, whereas SER is the major site for synthesis of lipid.
Fig. Endoplasmic reticulum