I have a basic question about DNA replication. As I understand, the double helix DNA replicates, and two double helix DNA strands are created. I understand that part. Now the question is, are these two DNA strands completely separated and floating about in the nucleus? If so, the next question is, how do the correct DNA pairs join together at the centromere to begin the mitosis process? How do each DNA strand know its exact counterpart to pair with? If they are not completely separated after DNA replication, how and where on the DNA strand are they attached? Thanks a lot. BTW, I am an engineer by profession with a with a curiosity in biology.