So the difference between these two molecules is the presence of different types of groups. So in this particular case, we have this nitrogen containing group and in this case we have an H. In this case we have a nitroge containing group. But in this case we have a carbon oxygen double bond. And that will play an important role in determining the types and the number of interactions that are formed between the different bases in the double stranded DNA molecule, as we'll see in our discussion of the double helix. So in RNA and DNA, these are the two purines that are common that exist. Now.