Now, once we form these regular patterns, the question is what exactly stabilizes these structures and allows them to exist in the first place? Well, it's the hydrogen bonds that exist between the amino acids in that polypeptide chain, as we'll see in just a moment, that allows each one of these secondary structures to actually exist in the first place. So let's begin with the alpha helix. So what exactly is an alpha helix? Well, an alpha helix is formed when we have our polypeptide chain and that polypeptide chain begins to twist to form a rodlike structure. And inside that rod like structure, we have the backbone.