DNA polymerase is found in: cells and all viruses all viruses some viruses cells cells and some viruses RNA-dependent RNA polymerase is found in: all viruses some viruses cells cells and all viruses cells and some viruses If a single new base is inserted into a gene and adds a single new base to mRNA in one location, the result will usually be: changing several amino acids in the protein a change in just one amino acid shortening of the protein because of the STOP signal no change in the amino acid cells and all viruses all viruses some viruses cells cells and some viruses .