Explanation:

Protein synthesis

The endoplasmic reticulum is a type of organelle which is found in the eukaryotic cell. It forms a continuous series of flattened sacs within the cytoplasm of eukaryotic cells. The main function of the ER is manufacturing and packaging system. Smooth endoplasmic reticulum (SER) is concerned with the synthesis of Cholesterol. SER is also involved in metabolism.