Question

Assertion: A monocistronic mRNA can produce several types of polypeptide chains.
Reason: The terminator codon is present on the mRNA.
A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion.
C. Assertion is correct but Reason is incorrect
D. Assertion is incorrect but Reason is correct

Answer 1

The mRNA or messenger RNA is the relation between the gene and the protein and is the product of an RNA polymerase transcribed gene.

Complete answer:
Ribonucleic acid (RNA) is a nucleotide polymer composed of phosphate, ribose sugar, and bases such as guanine, adenine, uracil and cytosine. There are various forms of RNA. The three main kinds of RNA are mRNA, tRNA and rRNA.

Genetic material is transmitted from the nucleus to the cytoplasm by mRNA. mRNA transcribes the DNA genetic code into a readable and usable form for making proteins. The mRNA molecule is considered to be monocistronic because it contains the genetic information for the translation of only one single protein. These mRNAs have single initiation and termination points and a single polypeptide chain is formed. Thus the statement is incorrect. The mRNA carries information on the amino acid sequence in polypeptides in the form of codons. Termination codons are stop codons that end the translation. They do not code for any amino acid. They are also present on mRNA. So the reason is correct.

Hence, the correct answer is option (D)

Note: During protein synthesis, every time an amino acid is linked to the protein, tRNA forms base pairs with its complementary sequence of mRNA molecules, ensuring that the required amino acid is incorporated into the protein.