Staying alive is no easy business. To keep from dying, cells must constantly juggle a wide range of tasks. They need to turn food into energy and produce the proteins and enzymes that choreograph crucial life processes. But no matter how efficient a cell is, in the end, it will die. To make sure its work does not die with it, every cell must be able to reproduce. This chapter reviews cellular respiration, protein synthesis, and cellular reproduction, the three crucial cellular life processes.