An anticodon is defined as what?

• A. The amino acid attached to tRNA
• B. The nitrogen base sequence on tRNA that is complementary to the corresponding mRNA sequence
• C. The codon on mRNA
• D. The ribosomal RNA sequence

Answer: (B)

In translation, the anticodon is the triplet sequence on tRNA that base-pairs with the codon on the mRNA. This complementary pairing ensures the tRNA brings the correct amino acid corresponding to that mRNA codon, so the amino acids are added in the proper order to build the protein. The anticodon is a feature of tRNA itself, while the amino acid attached to the tRNA is determined by aminoacyl-tRNA synthetase. It is not the codon on mRNA, nor part of the ribosomal RNA.