The next step in DNA replication is performed with an enzyme known as DNA polymerase. DNA polymerase is responsible for adding new nucleotides to the new strands according to the rules of base pairing. That is, A binding with T and G binding with C. DNA polymerase can add nucleotides only in a 5' (prime) to 3' (prime) direction. This means that on the leading strand it can add the nucleotides in a continuous fashion. On the lagging strand the DNA is going in the opposite direction. Therefore, it must add the newly synthesized DNA in small fragments. These fragments are known as Okazaki fragments. They will eventually be glued together to make a seamless strand of new DNA. It should also be noted that DNA polymerase does have some proofreading ability. It will check to make sure it has added the correct nucleotides during the replication process.