Proteins are made from chains of amino acids, which are tiny organic building blocks that come in twenty different varieties. All you need to do is to string them together into a chain, in whatever order you like, and voila, you have a protein. This principle enables life to construct a stunning variety of different things. For example, if you wanted to make a simple protein from a chain of ten amino acids, and you have twenty different amino acid types that you can choose from, this gives you a breathtaking 10,240,000,000,000 different possible proteins.
