Together Harvard University and XVIVO developed this 3D animation journey for Harvard's undergraduate Molecular and Cellular Biology students about the microscopic world of mitochondria. The animation highlights the creation of Adenosine Triphosphate (ATP) -- mobile molecules which store chemical energy derived from the breakdown of carbon-based food. ATP molecules act as a kind of currency, imparting chemical energy to power all the functional components of cellular activity. This piece is the second in a series of award winning animations XVIVO is creating for Harvard's educational website BioVisions at Harvard. The first program, Inner Life of the Cell, received international acclaim and can be seen both on our website and the BioVisions site. http://www.xvivo.net http://multimedia.mcb.harvard.edu/