Question

SER and RER can be distinguished with its presence in
(a)Protein synthesizing cells
(b)Protein and lipid synthesizing cells
(c)Carbohydrates and fat synthesizing cells
(d)Fat and protein-synthesizing cells

Answer 1

Hint: Rough endoplasmic reticulum is called rough because it appears rough when viewed from a microscope. Ribosomes that are present on top of them are responsible for this appearance. Smooth endoplasmic reticulum lacks them.

Complete answer:
The endoplasmic reticulum is a network or reticulum of tiny tubular structures like cisternae, tubules, and vesicles that are present throughout the cell. Their main function is to provide stability to the cytoplasm along with the microtubules and intracellular transport.
RER has ribosomes which are the protein machinery of the cell. So, we can understand that rough endoplasmic reticulum will be closely associated with the synthesis and transport of proteins.RER is present in the cells of those organs whose main function is to produce proteinaceous enzymes, hormones, and other compounds.
Whereas SER does not have any ribosomes on it so it will be primarily associated with the synthesis of fats and lipids. So SER is found in cells mainly producing steroid hormones such as estrogen.
Therefore SER and RER can be distinguished by its presence in fat and protein-synthesizing cells.
So, the correct answer is ‘Fat and protein-synthesizing cells.’

Note: -SER helps in detoxification of carcinogens in liver cells due to the presence of enzyme cytochrome ${ P }_{ 450 }$.
-SER is also present in muscle fibers where it performs the function of storage of ${ Ca }^{ 2+ }$ and is known as sarcoplasmic reticulum.
-The endoplasmic reticulum is part of the endomembrane system which also includes Golgi bodies, vacuoles, and lysosomes.