The codons for the various amino acids are given below. Answer the question.
Identify the degenerate codon from the following:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → GUU, GUG, GUA
A degenerate set is a group of different codons that code for the same amino acid.
Option (1) CCU, CAU, CGU — Incorrect. CCU is proline, CAU histidine and CGU arginine.
Option (2) UUG, UCG, UAG — Incorrect. UUG is leucine, UCG serine and UAG a stop codon.
Option (3) AUU, ACU, AAU — Incorrect. AUU is isoleucine, ACU threonine and AAU asparagine.
Option (4) GUU, GUG, GUA — Correct. A degenerate code means that more than one codon codes for the same amino acid. GUU, GUG and GUA all code for valine, so they show degeneracy.
NCERT Extract:
Genetic Code – “… The salient features of genetic code are as follows: (i) The codon is triplet. 61 codons code for amino acids and 3 codons do not code for any amino acids, hence they function as stop codons. (ii) Some amino acids are coded by more than one codon, hence the code is degenerate.”