Final answer:
Amino acids in proteins are coded by triplet bases in RNA known as codons. A codon is a sequence of three nucleotides that specifies a single amino acid during the process of genetic translation, adhering to the genetic code.
Step-by-step explanation:
Amino acids are the building blocks of proteins, and their sequence in a protein is determined by the nucleotide sequences in RNA. Specifically, amino acids are coded for by triplet bases in RNA called codons. The term codon refers to a sequence of three nucleotides that together form a unit of genetic code in a DNA or RNA molecule. For example, the DNA triplet CAC codes for the amino acid valine. The genetic code is thus based on these codons, with each amino acid being specified by a unique combination of three nucleotides.
The discovery that amino acids are encoded by groups of three nucleotides was a significant advancement in understanding genetic translation. Experiments by Francis Crick and Sydney Brenner demonstrated that inserting three nucleotides into a gene would lead to the production of a functional protein, despite inserting an extra amino acid, whereas insertion of one or two nucleotides would disrupt the entire sequence. This manifested the idea that genetic information is read in triplets, maintaining the genetic code integrity for subsequent amino acids.
Translation of mRNA involves reading these codons and converting the nucleotide-based genetic information into a sequence of amino acids, which will form a protein. Each of the 20 commonly occurring amino acids is defined within the mRNA by a triplet codon, illustrating the genetic code's role as a blueprint for protein synthesis.