Question

What is the major function of ER?

• A. Steroid and cholesterol synthesis
• B. Polypeptide formation
• C. Fatty acid synthesis
• D. All of the above

Answer 1

Answer: (D)

Endoplasmic reticulum (ER) is the membrane bound organelle. It is of two types rough endoplasmic reticulum and smooth endoplasmic reticulum. When ER is attached with ribosome called as granular or rough endoplasmic reticulum. It is abundant in cells engaged in active secretion and involves in the formation of the polypeptide into the lumen of ER.
Endoplasmic reticulum without attached ribosome is called as an agranular or smooth endoplasmic reticulum or SER. It is engaged in producing different types of lipids. SER also takes part in the synthesis of vitamins and carbohydrates and detoxification. SER occurs in adipose tissue, muscle cells, glycogen metabolising liver cells, steroid hormones (eg :testosterone and progesterone) synthesizing cells, retinal cells, leukocytes etc. Thus, the correct answer is option D.