“To make things even more challenging, cells must also be able to make all of their component molecular machines using only the resources that are available in the local environment. Think of the magnitude of this accomplishment. Many bacteria are able to build all of their own molecules from the a few simple raw materials like carbon dioxide, oxygen, and ammonia. A single bacterial cell knows how to build several thousand types of proteins, including motors, girders, toxins, catalysts, and construction machinery. This cell also builds hundreds of RNA molecules with different orderings of nucleotides, as well as a diverse collection of lipids, sugar polymers, and a bewildering collection of exotic small molecules. All of these different molecules must be created from scratch, using only the molecules that the cell eats, drinks, and breathes.”