Adenine may also be named 6-amino purine. How would you name the other four nitrogenous bases, using this alternative system? (O is indicated by 'oxy-,' and CH₃ by 'methyl.')

Video transcript

Hi everyone. Let's take a look at this practice problem together. Guanine is a nitrogenous base found in both D. N. A. And R. N. A. Which of the following is an alternative name for guan E. Now recall that there's two types of nitrogen in spaces. There's the pairings and the perimeter these well the pairings are guan ng and adding. Whereas the perimeter tings are sizing and timing. Now if we take a look at our possible answer choices, we can see that A. And B. Both in in peering, C. And D. Do not. And so we should eliminate C. And D. Because our sense guangming is appearing peering should be in the alternative name for it. And in fact see is the alternative name for side A. Zine. Whereas D. Is the alternative name for timing. Now the difference is between A. And B. Well there's an amino group in each of the names and recall that amino group is a functional group in H. Two. And then A also has a hydroxy group on the number six adam position. So let's take a look at the structure of both guanine and adenine. And see if we can identify what our answer will be. So here we have chemical structures as well as the numbering of the base atoms. So you can see we have on adding and the numbering and guanine is 123456789. Let's take a look at guanine. It's amino group is here on the second base atom And so again in in comparison, the Amino Group is here on the # six. Looking at the two options are option most makes sense that our answers A two amino six hydroxy peering. However, how do we explain that? Hydroxy group? Well, in guanine, this functional group up here is a carbon L. C. Double bond O. So this is a carbon carbon Neil group. Well, when nucleotides bond, this would actually become bonded to a hydrogen and this would be the hydroxy group that's in the name. So that's how the hydroxy group fits in. And it you can see it's on the sixth base atom. So our answer is going to be a two amino six hydroxy period. Alright everyone. I hope you found this helpful. And I'll see you soon for the next practice problem.