Question

Which of the classes of RNA molecule is never found in the cytosol?
A. Ribosomal RNA
B. Transfer RNA
C. Messenger RNA
D. Primary mRNA transcript

Answer 1

Hint: Ribonucleic acid is a polymeric molecule that would be involved in gene coding, decoding, regulation, and expression in biology. Nucleic acids include RNA and deoxyribonucleic acid. Ribonucleic acid (RNA) is a vital biological macromolecule found in all living organisms.
It is primarily engaged in protein synthesis, conveying messenger instructions from DNA, which provides the genetic information essential for life's development and maintenance.
RNA has many tasks, including translating genetic information into the cell's molecular machines and structures and regulating gene activity during development, cellular differentiation, and changing surroundings. RNA is a one-of-a-kind polymer.

Complete answer:
Option A: rRNA is found in the cytoplasm of a cell, which also contains ribosomes. The translation of mRNA into proteins is directed by rRNA.
So, option A is incorrect.
Option B: Transfer RNA (tRNA) accomplishes this by transporting an amino acid to the ribosome, a cell's protein-synthesis machinery. Protein synthesis is based on the mRNA code when a 3-nucleotide codon in a messenger RNA (mRNA) is complimented by a 3-nucleotide anticodon of the tRNA.
So, option B is not correct.
Option C: A single-stranded RNA molecule called messenger RNA (mRNA) is complementary to one of a gene's DNA strands. The mRNA is an RNA form of the gene that leaves the nucleus and travels to the cytoplasm, where it is translated into proteins.
So, option C is not correct.
Option D: In the cell and nucleus, all RNAs have diverse roles to play. Ribosomal RNA is found in the cytoplasm near ribosomes and aids in the creation of larger and smaller ribosomal subunits as well as the formation of proteins during the translation process. Messenger RNA is found in the cytoplasm and aids in the transmission of genetic information from the nucleus to the cell. A primary mRNA transcript is a premature mRNA that forms when DNA transcribes it. These are later changed throughout the translation process.
So, option D is correct.

Therefore, Option D is the correct answer.

Note:
Messenger RNA is made in the nucleus of a cell and then exported to the cytoplasm, where it serves as a template for the production of proteins. The template is destroyed once this process is completed. The flow of genetic information is affected by the rate at which messenger RNA is produced.
Recent data suggests, however, that the rate at which messenger RNA is destroyed in the cytoplasm might affect how much of it is produced in the nucleus, i.e., if significant levels of RNA are destroyed, production is halted. Certain viruses, for example, have proteins that speed up the degradation of messenger RNA in order to seize control of the host cell.