In this video, we're going to begin our lesson on hydrogen bonding, and so a hydrogen bond is commonly abbreviated as just an "H bond," and that's because the letter H is the chemical symbol for hydrogen. And so, a hydrogen bond or an H bond is really just defined as an interaction between a highly electronegative atom such as either fluorine, oxygen, or nitrogen, and of course, a hydrogen atom itself. How could you have a hydrogen bond without a hydrogen atom? And so every hydrogen bond is going to have a hydrogen atom involved. However, the highly electronegative atom will vary.
Sometimes it will be either fluorine, other times it will be oxygen, and other times it will be nitrogen. But what can help you remember the highly electronegative atoms that form hydrogen bonds is that hydrogen bonds are pretty fun, and so you can think "FON" here sounds like fun, and so those are the three electronegative atoms that can help form hydrogen bonds. And so notice down below in our image we're showing you a few examples of hydrogen bonds and we'll talk about them here shortly, but one thing to note about these hydrogen bonds is that individually the H bonds or the hydrogen bonds are really really weak. However, collectively if you have lots and lots of hydrogen bonds forming they can be quite strong. And so these hydrogen bonds are actually important in several different areas of biology including the properties that are found in water, which we'll get to talk more about later in our course in a different video, and hydrogen bonds are also really important for the structure of macromolecules, which we'll get to talk more about these macromolecules later in our course as well.
But down below in our image, notice that we're showing you some examples of hydrogen bonds in biology. On the left, we're showing you how water molecules can form hydrogen bonds, and so notice that we have these three different water molecules right here H2O, and notice that through hydrogen bonding, they can actually form interactions between these different water molecules. And so what you'll notice is that this yellow bond represents the hydrogen bond and notice that it's forming between a hydrogen atom as we indicated up above and another highly electronegative atom, in this case, showing oxygen here in the water molecules, and so you can see another oxygen here and another hydrogen right here. Once again the hydrogen bond is the bond that forms between the two. Now, that is going to be very important; the hydrogen bonding in water is going to be very important for specific properties that water has that are really important for life.
And once again, we'll talk about these properties of water later in our course in a different video. But it's important to know that water does form hydrogen bonds. Now, over here on the right-hand side, we're showing you how nucleotides can also form hydrogen bonds. And so, over here we're showing you one nucleotide and over here we're showing you another nucleotide and notice that between these two nucleotides there are hydrogen bonds that are forming. Notice that this first hydrogen bond up here at the top is forming between a hydrogen atom and a highly electronegative oxygen atom, but this other hydrogen bond down below right here is forming between a hydrogen atom and another highly electronegative atom of a nitrogen atom, and so remember that, the highly electronegative atom can vary.
It can either be fluorine, oxygen, or nitrogen, and so here in this scenario you can see that it's forming between nitrogen and a hydrogen and an oxygen and a hydrogen. And so, don't worry too much about what nucleotides are right now. We'll talk more about nucleotides later in our course in a different video. For now, what you should know is that these nucleotides are going to be found in the structure of DNA. And later in our course when we talk more about DNA, we'll revisit this idea of how hydrogen bonds form between DNA structures.
But for now, this here concludes our introduction to hydrogen bonding and we'll be able to get some practice applying these concepts in our next few videos. So I'll see you all there.
