In this lecture, we will briefly review the principles of physics, central metabolism, and cell biology that make health possible. This exercise is appropriate for those of us who have set before ourselves the problem of understanding and preserving life processes, because it is through the medium of a cell that energy creates life. We are aware that life processes require a complex set of biochemical reactions. But that is not enough. Not only are complex reactions necessary, but superimposed on this essential requirement is the necessity to build and maintain a dynamic cellular structure. Chemical energy builds cells. In this lecture, we will see how cells extract energy from the entropic dissolution of the universe, how the extracted energy is used to build cell structure, and how cell structure determines cell function.