Endoplasmic Reticulum

The endoplasmic reticulum (ER) is a system of interconnected channels and flattened sacs within the cytoplasm of cells, which forms an extensive and continuous network of membranes. It is involved in a variety of important cellular functions, including protein folding, transport, enzymatic reactions, and storage. Additionally, the ER provides compartments necessary for the assembly and export of various proteins including glycoproteins, secretory proteins, and membrane proteins. As such, it is essential for the structural and functional integrity of the cell.