How is the genetic code read during translation?

How is the genetic code read during translation?

• A. In pairs of nucleotides
• B. In quadruplets
• C. In single nucleotides
• D. In triplets called codons, from a start codon to a stop codon

Answer: (D)

The genetic code is read in triplets called codons. Each codon, made of three nucleotides, specifies one amino acid (or a stop signal). Translation begins at a start codon on the mRNA, which also sets the reading frame, and the ribosome then progresses along the message in consecutive, nonoverlapping triplets from 5' to 3' until it reaches a stop codon. This triplet, start-to-stop scheme creates the correct sequence of amino acids for a protein. Reading in pairs, quadruplets, or as single nucleotides would not consistently provide the one-amino-acid-per-codon mapping or a clear stop signal, so the triplet codon model best explains how translation works.

The genetic code is read in triplets called codons. Each codon, made of three nucleotides, specifies one amino acid (or a stop signal). Translation begins at a start codon on the mRNA, which also sets the reading frame, and the ribosome then progresses along the message in consecutive, nonoverlapping triplets from 5' to 3' until it reaches a stop codon. This triplet, start-to-stop scheme creates the correct sequence of amino acids for a protein. Reading in pairs, quadruplets, or as single nucleotides would not consistently provide the one-amino-acid-per-codon mapping or a clear stop signal, so the triplet codon model best explains how translation works.