Which statement best describes the relationship between triplet codes and amino acids?

• A. Triplet codes specify nucleotides, not amino acids.
• B. Triplet codes are unrelated to amino acids.
• C. The same triplet codes different amino acids.
• D. Sets of three nucleobases form a triplet code that codes for amino acids.

Answer: (D)

Triplets of nucleotides, called codons, carry the instruction to add a specific amino acid during protein synthesis. Each codon is formed by three nucleobases and maps to an amino acid (or a stop signal). There are 64 possible codons, reflecting redundancy where several codons code for the same amino acid. This is why sets of three nucleobases form a triplet code that codes for amino acids. The other statements misstate the relationship: codons aren’t about specifying nucleotides alone, they are connected to amino acids; they aren’t unrelated to amino acids; and a single codon doesn’t code for different amino acids.