Question

Which one of the following triplet codons is a chain termination codon?
(A) UGU
(B) AAU
(C) UUG
(D) UAG

Answer 1

Hint: Triplet codons are the codes for the one certain amino acid which is expressed in the three nucleotides. By the process of the transcription the DNA gene is converted into the messenger RNA which is expressed using the code represented by the letters of A, C, G and U.

Complete answer:
The chain termination codon is the codon which are the set of three bases of the DNA nucleotide or which are the three complementary bases in the RNA which is used to terminate the polypeptide chain. These are specified as termination codons or the stop codons or the nonsense codons.

The codons UAA, UAG and UGA are the stop codons that are used to end the polypeptide chains. These occur as the complementary bases in the messenger RNA which is converted from the DNA by the transcriptase enzyme. The letter U resembles the uracil, the letter A resembles the adenine, the letter G represents the guanine and the letter C resembles the cytokine. From the given option, UAG is the triplet termination codon.

Hence the correct answer is OPTION(D)

Note: There are 64 triplet codons of the amino acids are present out of which only 61 triplet codons are used to express the specific amino acids, other 3 triplets are called as stop codons used to design the termination of the transcription of the genetic material.