So recall that any given DNA molecule actually consists of two individual and complementary single stranded DNA molecules. And these two single stranded molecules basically combine via an antiparallel fashion to form our double helix. And the bonds that hold our two individual complementary single stranded DNA molecules are hydrogen bonds between our adjacent nitrogenous basis. Now, the question is, what exactly is the first process that takes place when our DNA replicates? Well, before our DNA is replicated, what must happen is our double stranded DNA molecule must actually unwind. So we see that in order for replication to actually occur, the two strands of DNA must first unwind.