So proteins basically consist of these subunits, these building blocks we call amino acids. And there are 20 types of amino acids that exist inside our body. So proteins are built from the selection of 20 different amino acids. And the fact that we have 20 different amino acids means we have a great variety of possible sequences for any given protein. And to demonstrate what we mean by that, let's consider a protein that contains only ten amino acids. So we have amino acid one, amino acid two, amino acid three, all the way to amino acid number ten.