Q163 / 180 · AIIMS 2018 (26 May) · Zoology

Assertion: Amber codon is a termination codon. Reason : If in $m$ RNA, a termination codon is present, the protein synthesis stops abruptly whether the protein synthesis is completed or not.

  • A
    If both assertion and reason are true and reason is the correct explanation of assertion.
  • Correct answer
    B
    If both assertion and reason are true but reason is not the correct explanation of assertion.
  • C
    If assertion is true but reason is false.
  • D
    If both assertion and reason are false.

Solution

Nonsense codon is a set of three nucleotides for which there is no corresponding tRNA molecule to insert an amino acid into the polypeptide chain. Protein synthesis is hence terminated and the completed polypeptide released from the ribosome. Three stop codons are UAA (ochre), UAG (amber) and UGA (opal).

Hence, the correct answer is option: 'B'.

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