Identify the correct combination of salient features of the genetic code.
(A) AUG has dual functions as it codes for methionine (met), and also act as initiator codon.
(B) Some amino acids are coded by more than one codon, hence the code is degenerate.
(C) UAA, UAG, UGG are stop terminator codons.
(D) The codon is read in mRNA in a continuous fashion and there are no punctuations.
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → (A), (B) and (D) only
The genetic code is the set of three-letter codons in mRNA that tell which amino acid goes where in a protein.
(A) AUG has dual functions as it codes for methionine (met), and also act as initiator codon. Correct. AUG starts translation, and it also places methionine in the chain.
(B) Some amino acids are coded by more than one codon, hence the code is degenerate. Correct. There are 61 codons for only 20 amino acids, so many amino acids have more than one codon.
(C) UAA, UAG, UGG are stop terminator codons. Incorrect. The three stop codons are UAA, UAG and UGA. UGG is not a stop codon; it codes for the amino acid tryptophan.
(D) The codon is read in mRNA in a continuous fashion and there are no punctuations. Correct. The codons follow one another without any gap or spacer. So adding or deleting one base shifts the whole reading frame after it.
NCERT Extract:
Genetic Code – …
