Assertion: UAA, UAG and UGA terminate protein synthesis.
Reason: They are not recognised by tRNA.
(a) If both Assertion and Reason are correct and Reason is the correct explanation of Assertion.
(b) If both Assertion and Reason are correct, but Reason is not the correct explanation of Assertion.
(c) If Assertion is correct but Reason is incorrect.
(d) If both the Assertion and Reason are incorrect.
(a) If both Assertion and Reason are correct and Reason is the correct explanation of Assertion.
Explanation:
Synthesis of polypeptide terminates when a nonsense codon of mRNA reaches the A– site. There are three nonsense codons– UAA, UAG and UGA. These codons are not recognised by any of the tRNAs. Therefore, no more aminoacyl tRNA reaches the A site. The P– site tRNA is hydrolysed and the completed polypeptide is released in the presence of a release factor.