What is the set of three sequential nucleotides that encodes for a particular amino acid?

• A. codon
• B. anticodon
• C. triplet
• D. nucleotide

Answer: (A)

In the genetic code, three-nucleotide units in mRNA specify amino acids. Each codon is read by the ribosome during translation and corresponds to one amino acid that will be added to the growing polypeptide. An anticodon on tRNA is the complementary three-nucleotide sequence that pairs with the codon to bring in the correct amino acid, but it’s the codon itself on the mRNA that encodes the specific amino acid. A nucleotide is a single unit, and a triplet could describe any three nucleotides without specifying its role in encoding. Because these three-nucleotide sequences in mRNA determine which amino acids are incorporated, the proper term for this entity is codon. There are 64 possible codons, reflecting the genetic code’s redundancy and including start and stop signals.