In this video, we're going to talk a little bit more about nucleotides. We already know from our last lesson video that nucleotides are the monomers of nucleic acids. But really, just one single nucleotide monomer consists of 3 different components that we have numbered down below here in our text. Also, notice that we have the 3 components color coordinated with these backgrounds; the 1st component has a pink background, the 2nd component has a blue background, and the 3rd component has a yellow background. These background colors correspond with the colors that you see down below in our image. So, the very first component of a nucleotide monomer is a phosphate group, which, recall from our previous lesson videos, is just a functional group that looks like this down below, with a phosphorus atom in the middle. The second component of a nucleotide monomer is a pentose sugar, and all the "pentose" part means is that this sugar has a 5-membered ring. When we take a look at the blue component down below, notice that there is a ring and the ring has a total of 5 members in it. That makes this a pentose sugar. Then, the third and final component of a nucleotide monomer is a nitrogenous base. It turns out that the nitrogenous base can vary, and there are 5 different types of nitrogenous bases. We'll talk more about those 5 different types of nitrogenous bases in our next lesson video. But for now, taking a look down below, we can see the 3rd component is here in yellow, the nitrogenous base.
In our last lesson video, we were abbreviating nucleotides using symbols that look somewhat like this in the corner. But really, just one of these nucleotide monomers that we see here in the corner consists of 3 components. Once again, the phosphate group here, the sugar component here, and the nitrogenous base up here. You can think that this little nucleotide consists of these three components like what you see here. Now this leads us to different types of nucleotides. There are DNA nucleotides or deoxyribonucleic acid nucleotides. DNA is the abbreviation for the molecule called deoxyribonucleic acid. Then, there are also ribonucleic acid nucleotides or RNA nucleotides. The DNA and the RNA nucleotides, they use different sugars, amongst also sometimes using different nitrogenous bases, which we'll talk more about as we move forward in our course. But if we take a look at our image down below, notice that we're comparing DNA nucleotides versus RNA nucleotides. The left half of our image over here is specifically for the DNA nucleotide, and the right half of our image over here is specifically for the RNA nucleotides. Notice that both nucleotides have the 3 components that we talked about before; the pink component here, which is the phosphate group, this one also has a phosphate group, the RNA nucleotide. They both also have a pentose sugar, and so, you can see that the blue part is here. Then they both also have nitrogenous bases. Here specifically, we've said that the nucleotides of DNA and RNA use different sugars. So we're going to focus in on the blue part here and over here. Notice that the RNA over here on the right uses a ribose sugar, whereas the DNA over here on the left uses a deoxyribose sugar. The "deoxy" part here means one less oxygen. "Oxy" means oxygen and "d" means without. So, the deoxyribose sugar has one less oxygen in comparison to the ribose sugar over here. What this means is that the ribose sugar is going to have a hydroxyl group, an OH group at this position, and the deoxyribose over here is not going to have the extra oxygen; it's just going to have a hydrogen here. The deoxyribose has one less oxygen comparing this position to this position over here. We'll get to talk more about DNA and RNA as we move forward in our course, but again, one of the biggest differences is that they use different sugars. DNA uses deoxyribose sugar and RNA uses ribose sugar. This here concludes our introduction to nucleotides, and we'll be able to get some practice applying these concepts as we move forward in our course. So, I'll see you in our next video.