Question

Which of the following is true about rough endoplasmic reticulum?
A. It is studded with ribosomes that form a bumpy coat.
B. It functions in lipid synthesis.
C. It contains cellulose, which gives the membrane rigidity and structure.
D. It lacks the ribosome characteristics of the cytosol.
E. It engages in lipid synthesis, which gives it a rough texture.

Answer 1

Hint: The rough endoplasmic reticulum is an organelle found in eukaryotic cells. It is made-up of cisternae, tubules and vesicles. The cisternae are made-up of flattened membrane disks that are involved in the modification of proteins.

Complete step by step answer: Rough endoplasmic reticulum is named for its rough appearance, which is due to ribosomes attached to its outer cytoplasmic surface. These are found all across the cell but the density is higher near the nucleus and the Golgi apparatus. Rough endoplasmic reticulum contains ribosomes which are also called ‘membrane-bound’ and for many proteins, they are responsible for their assembly. Protein synthesis begins in the cytosol with a process called translation, in which the protein is assembled from an RNA sequence. In the Rough endoplasmic reticulum, proteins may undergo slight modifications, such as having their signal sequences cleaved or undergo glycosylation.
The abnormalities in rough endoplasmic reticulum structure and function are associated with certain kinds of human diseases. The presence of ribosomes on rough endoplasmic reticulum forms a bumpy coat. Another type of endoplasmic reticulum is also present in the cell called the smooth endoplasmic reticulum.
Hence, the correct answer is option A.

Note: The major difference between the smooth endoplasmic reticulum and rough endoplasmic reticulum is that though they have the same type of membrane, they are of different shapes. Rough endoplasmic reticulum looks like disks or sheets of the bumpy membrane, while a smooth endoplasmic membrane looks like tubes. The most common and easy difference between them is that rough endoplasmic reticulum has ribosomes present, whereas the smooth endoplasmic reticulum lacks ribosomes.