A triplet of nucleotide bases in mRNA that specifies an amino acid or the initiation or termination of a polypeptide sequence is called what?

A triplet of nucleotide bases in mRNA that specifies an amino acid or the initiation or termination of a polypeptide sequence is called what?

• A. Genetic code
• B. Codon
• C. Polypeptide
• D. Amino acids

Answer: (B)

Translation reads three-nucleotide units in mRNA, and that unit is called a codon. A codon each time tells the ribosome which amino acid to add next, or when to start or stop building the polypeptide. The start codon is AUG, which also codes for methionine, signaling where translation begins, while the stop codons—UAA, UAG, and UGA—signal termination. The overall set of rules that maps codons to amino acids is the genetic code, but the specific triplet in mRNA being read is the codon. The product of this process is a polypeptide chain made of amino acids.

Translation reads three-nucleotide units in mRNA, and that unit is called a codon. A codon each time tells the ribosome which amino acid to add next, or when to start or stop building the polypeptide. The start codon is AUG, which also codes for methionine, signaling where translation begins, while the stop codons—UAA, UAG, and UGA—signal termination. The overall set of rules that maps codons to amino acids is the genetic code, but the specific triplet in mRNA being read is the codon. The product of this process is a polypeptide chain made of amino acids.