So let's take a look at one of these amino acids. Let's suppose this amino acid here, the fourth amino acid in our polypeptide chain. So the nitrogen is more electronegative than the H. And what that means is this H will have a partial positive charge, and this partially positive charge on the H will basically ensure that if we have some other atom that is electronegative in close proximity, then in that case, this will be donated to that electronegative atom. And we're going to form an H bond. So that is a hydrogen bond donor. Now let's take a look at this Carbonal group of this same amino acid.