The only difference is the sugar component contains a three prime carbon that does not contain a hydroxyl group. So remember, in a normal deoxy nucleus triphosphate, the presence of the hydroxyl group on the three prime carbon allows DNA polymerase to actually form a phosphodiastor bond with the next nucleotide in line. So in the process of DNA synthesis, when we're replicating a DNA strand, the DNA polymerase needs this hydroxyl group to be present on the three prime carbon to actually form the phosphodiaester bond. And if that hydroxyl group is not present, as in this case, it will not be able to form that phospholdiaester bond. And so DNA replication would essentially stop. And so what this DD NTP molecule is used for in this method is to basically stop the process of DNA replication.