One of the additional functions of Smooth Endoplasmic Reticulum (SER)

One of the additional functions of Smooth Endoplasmic Reticulum (SER) is

protein synthesis
lipid synthesis
storage of biomolecules
detoxification of toxic substances
This question was previously asked in
UPSC NDA-2 – 2018
The Smooth Endoplasmic Reticulum (SER) performs several key functions distinct from the Rough Endoplasmic Reticulum (RER), which is primarily involved in protein synthesis. These functions of SER include lipid synthesis (phospholipids, steroids), detoxification of drugs and poisons (especially in liver cells), metabolism of carbohydrates, and storage of calcium ions (critical for muscle contraction). Among the given options, detoxification of toxic substances is a well-established function of SER.
– RER has ribosomes on its surface and is involved in synthesizing and modifying proteins destined for secretion or insertion into membranes.
– SER lacks ribosomes and is involved in metabolic processes.
– Key functions of SER include lipid synthesis, detoxification, carbohydrate metabolism, and calcium storage.
For example, in hepatocytes (liver cells), the SER contains enzymes that catalyze reactions to detoxify lipid-soluble drugs and harmful metabolic products by making them more water-soluble for excretion from the body. SER is also extensive in cells that synthesize steroids (like hormone-producing cells).