Final answer:
A triplet of nucleotides that corresponds to an amino acid is called a codon. It's a part of the genetic code represented in mRNA that determines the sequence of amino acids in proteins during translation.
Step-by-step explanation:
A triplet of nucleotides that corresponds to an amino acid is known as a codon. This consecutive sequence of three nucleotides on an mRNA molecule corresponds to a specific amino acid during the process known as translation. In the genetic code, one amino acid is specified by or incorporated in place of such a triplet. Therefore, the genetic code consists of various codons that dictate the sequence of amino acids in a protein. Each codon serves as a genetic code "word" that is recognized and translated by the cell's machinery to add the respective amino acid to a growing polypeptide chain during protein synthesis.
Moreover, the genetic code is described as degenerate, which means that a given amino acid may be encoded by multiple codons. The sequence of codons in the mRNA dictates the order of amino acids in the synthesized protein, ultimately determining its structure and function. For example, the DNA triplet CAC corresponds to the amino acid valine, and during transcription, it is copied into mRNA as the codon GUG, which the ribosome then translates into valine during protein assembly.