Which of the following is a terminator codon?

The correct answer is Option (4) → All of these

The genetic code has 64 codons. 61 of them code for amino acids, and three do not code for any amino acid. These three are the stop or terminator codons, and they mark the end of translation. When the ribosome reaches one of them, a release factor binds and the polypeptide is released.

Option (1) UAA — Correct statement, but it is only one of the correct points, so on its own it is not the answer. UAA does not code for any amino acid and stops translation.

Option (2) UAG — Correct statement, but it is only one of the correct points, so on its own it is not the answer. UAG is also a stop codon with no amino acid assigned to it.

Option (3) UGA — Correct statement, but it is only one of the correct points, so on its own it is not the answer. UGA is the third stop codon of the code.

Since all three are terminator codons, Option (4) is the answer.

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.”
Genetic Code – “… (v) AUG has dual functions. It codes for Methionine (met), and it also act as initiator codon. (vi) UAA, UAG, UGA are stop terminator codons.”