The triplet of nucleotides in mRNA that specifies an amino acid is called what?

• A. Codons
• B. Anticodon
• C. mRNA
• D. tRNA

Answer: (A)

The main idea is how the genetic code is read during protein synthesis. The ribosome translates the mRNA in three-nucleotide units, and each of these units specifies which amino acid should be added next. That three-nucleotide unit on the mRNA is a codon. The codon-to-amino-acid mapping is what defines the genetic code, with some codons signaling termination of the chain. The molecule that brings each amino acid is tRNA, which has an anticodon that pairs with the codon, ensuring the correct amino acid is incorporated. So the triplet of nucleotides in mRNA that specifies an amino acid is a codon. The other terms describe different elements: anticodon is the tRNA’s triplet that recognizes the codon, mRNA is the template carrying the codons, and tRNA is the adaptor that delivers amino acids.