So the simplest level of complexity that describes the structure of proteins is the primary structure. So the primary structure describes the specific sequence of amino acids within our protein, within our polypeptide. Now, it turns out that every single protein inside our body has its own unique sequence of amino acids. And it's the primary structure, it's the sequence of amino acids that actually determines what the final structure of that protein is. And that's a very important point to remember. It's the primary structure, it's the specific sequence of amino acids in that polypeptide that determines the final three dimensional structure of that polypeptide.