Thus, a triplet code introduces the problem of there being more than three times the number of codons than amino acids. Either these “extra” codons produce redundancy, with multiple codons encoding the same amino acid, or there must instead be numerous dead-end codons that are not linked to any amino acid.

What happens to the extra codons?

That extra word represents an extra codon in the DNA, and so an extra amino acid residue in the protein chain. … It will change one codon completely, and introduce an extra codon. That would give you one different amino acid and one extra amino acid in the chain.

What do the other 3 codons do?

The three-letter nature of codons means that the four nucleotides found in mRNA — A, U, G, and C — can produce a total of 64 different combinations. Of these 64 codons, 61 represent amino acids, and the remaining three represent stop signals, which trigger the end of protein synthesis.