During translation, which molecule carries the codon sequence that determines the order of amino acids?

• A. tRNA
• B. mRNA
• C. rRNA
• D. DNA

Answer: (B)

During translation, the order of amino acids is dictated by the sequence of codons on the messenger RNA. Each three-nucleotide codon on the mRNA specifies a particular amino acid, and the ribosome reads these codons in order to assemble the polypeptide. Transfer RNA brings the corresponding amino acids to the ribosome, with anticodons that pair to the mRNA codons, but the actual template carrying the codon sequence is the mRNA. DNA stores the original gene sequence but is not read directly during translation, and ribosomal RNA helps form the ribosome and catalyze peptide bonds rather than carrying the codon information. So the molecule that carries the codon sequence determining the order of amino acids is messenger RNA.