So what the DNA polymerase molecule does is it catalyzes the formation of a phosphor diester bond by adding a deoxy nucleotide triphosphate, the dNTP, onto that growing polypeptide chain. And in the process, every time we add the deoxyribonucleotide onto that growing chain in a stepwise fashion, we release the Pyrophosphate molecule and we'll discuss what the Pyrophosphate molecule is in much more detail when we discuss the replication process. So in this lecture, our goal is simply to discuss what the general function of DNA polymerase is. Now, for DNA polymerase to actually function effectively, it has to have three different things. So A, B and C and D. We simply discuss one important fact about the DNA polymerase molecule. So let's begin with A.