Question

Which codon is known for its dual function as both an initiator codon and the codon for Methionine?

• A. UAA
• B. AUG
• C. UAG
• D. UGA

Hint:

AUG is the universal start codon in most organisms and codes for methionine at the beginning of protein synthesis.

Answer 1

The Correct Option is B

Concept: In genetic coding, codons are sequences of three nucleotides present in messenger RNA (mRNA) that specify particular amino acids during protein synthesis. Each codon corresponds to a specific amino acid or signals the start or termination of translation.

Step 1: Understanding start codons.
Protein synthesis begins at a specific codon called the start codon. This codon signals the ribosome to begin translation and establishes the correct reading frame.

Step 2: Role of AUG.
The codon AUG performs two important roles:
• It acts as the initiator codon that signals the beginning of protein synthesis.
• It codes for the amino acid Methionine.

Step 3: Comparison with other codons.

• \(UAA\), \(UAG\), and \(UGA\) are stop codons that terminate protein synthesis.
• Only \(AUG\) functions as both a start codon and a codon for methionine.

Step 4: Conclusion.
Therefore, the codon that has the dual function of initiation and coding for methionine is AUG.