Alright. So here we have an example problem that's asking what is the difference between the sugar group in DNA and the sugar group in RNA? And we've got these 5 potential answer options down below. Now after reading through each of these 5 potential answer options, there's one that we can eliminate right off the bat and that is going to be option e, which says the sugar group in DNA and RNA are not different. Of course, we know that this is false, that DNA and RNA have different sugar groups from our last lesson video.
Now, option a here says the sugar group in DNA has a hexose while the sugar group in RNA is a pentose. Now, a hexose, we did not mention at all in our last lesson video. We only talked about pentoses, and recall pentoses are sugars with a 5-membered ring, whereas hexoses are sugars with a 6-membered ring. But we didn't mention anything about hexoses in our last lesson video, and this is simply not true. Option a is not true.
Both DNA and RNA use a pentose sugar. Now, option b says the sugar group in DNA has an extra hydroxyl group than the sugar group in RNA. Recall that hydroxyl groups are OH groups, so they have an oxygen in them. And recall that DNA stands for deoxyribose, and deoxy means one less oxygen. If DNA had an extra hydroxyl group, that would mean it would have an extra oxygen, but that is not the case with DNA.
It is deoxy, so that means it has one less, not one extra hydroxyl group. And so for that reason, we can go ahead and eliminate answer option b. And then, of course, looking at answer option c here, it says the sugar group in DNA has one less hydroxyl group than the sugar group in RNA. This is going to match up with what we were just talking about, and this is going to be the correct answer here for this example problem. Now option d here says the sugar group in DNA contains one less carbonyl group than the sugar group in RNA, but the carbonyl group is not the right functional group here.
Remember, carbonyl groups are C double bond O groups. But we're looking at the hydroxyl group, not the carbonyl group. So that's why option d is incorrect. And so, once again, option c here is the correct answer for this example problem. And if we were to take a look at our last lesson video here, we can see that the DNA nucleotide over here has one less oxygen in comparison to the ribose which has an extra oxygen atom.
And so, the deoxy therefore has one less hydroxyl group, relative to the ribose which has one additional hydroxyl group. And so that concludes this video, and I'll see you all in our next one.