Why do some mutations to DNA structure not result in a change of the produced polypeptide?

This is a question which candidates would be expected to recall knowledge about the degenerate nature of the genetic code. A degenerate genetic code means that more than one codon can result in the same amino acid being translated and added to the amino acid chain which forms a polypeptide protein. In this way, a mutation may not necessarily result in an incorrect protein being produced. For example, the codon UCU codes for the amino acid serine, as does UCA. [you do not need to know specific examples, but this helps to demonstrate the principle] A codon is a sequence of 3 DNA or RNA nucleotides that corresponds to a specific amino acid or stop signal.