And notice in the case of guanine and cytosine, we have three hydrogen bonds. And in the case of adenine and thymine, we only have two of these hydrogen bonds. So that means the guanine cytosine pair forms a more stable attraction than our adenine, thymine. So if a given DNA molecule contains more guanine cytosine pairs, that means the bonding between our two single stranded DNA molecules is stronger. Now, one other important thing that we have to mention about the double helix is the directionality of our single stranded DNA. So let's take a look at this single stranded DNA that only consists of two nucleotides.