So, in step one, what we essentially want to do is we want to denature the double helix structure of the DNA. We want to separate the two strands of DNA, and the way that we're going to separate them is by adding sodium hydroxide. So remember, a base or an acid, if we mix the DNA in either a basic or acidic solution, in this case a basic, the base will essentially ionize the bases of our DNA molecule and that will disrupt and break the hydrogen bonds. And so if we take the double strand DNA molecule and we add sodium hydroxide, we produce these two individual strands of DNA. Now, one of these single strands of DNA can actually be chosen for the sequencing process. Now, it doesn't matter which one of these DNA strands we choose, because if we choose this one, for example, then once we determine the sequence of this DNA strand, we can easily determine what the sequence of the other strand is because these two strands are complementary.