What is the function of the endoplasmic reticulum?

The endoplasmic reticulum (ER) plays a critical role in the synthesis and processing of proteins and lipids within cells. It exists in two forms: rough ER, which is studded with ribosomes, and smooth ER, which does not have ribosomes. The rough ER is primarily involved in the synthesis of proteins that are either secreted from the cell, incorporated into the cell's plasma membrane, or sent to an organelle. The smooth ER, on the other hand, is involved in lipid synthesis, metabolism, and the detoxification of certain chemicals.

Furthermore, the endoplasmic reticulum acts as a quality control hub, ensuring that proteins are properly folded and modified before they are dispatched to their final destinations in the cell. This multifunctional role makes the endoplasmic reticulum crucial for maintaining the cell's health and functionality, emphasizing its involvement in the synthesis of both proteins and lipids.