The correct term is "endoplasmic reticulum" (singular) or "endoplasmic reticula" (plural).
The endoplasmic reticulum (ER) is a complex, membrane-bound organelle found in eukaryotic cells. It plays a crucial role in various cellular processes, including protein synthesis, lipid metabolism, and calcium storage.
The ER is made up of a network of membrane-enclosed sacs, tubules, and cisternae (flattened sacs). There are two types of endoplasmic reticulum: rough endoplasmic reticulum (RER) and smooth endoplasmic reticulum (SER).
1. **Rough Endoplasmic Reticulum (RER):** Studded with ribosomes on its cytoplasmic surface, giving it a "rough" appearance. RER is involved in the synthesis and modification of proteins that are either secreted from the cell, incorporated into the cell's membrane, or destined for certain organelles.
2. **Smooth Endoplasmic Reticulum (SER):** Lacks ribosomes on its cytoplasmic surface, making it look "smooth." SER is involved in various functions, including lipid metabolism (synthesis of lipids and steroids), detoxification of drugs and toxins, and storage of calcium ions.
Together, the endoplasmic reticulum plays a vital role in maintaining the proper functioning of the cell, ensuring the correct synthesis and transport of proteins and lipids, and regulating cellular activities.