Q. I’m quite sure I’ve heard you say that the mitochondria are the powerhouse of the cells but what do they do?

A. Mitochondria provide you with energy, including the energy you needed to ask the question. They are tiny energy factories inside most cells that generate most of the cell's supply of chemical energy that is stored as adenosine triphosphate (ATP). The energy produced powers everything you do. In the brain, vast amounts of energy are needed to transmit information across the synapse, or the space between neurons, to power functions that allow you to learn, think, feel, remember, and maintain cognition in the aging process. The brain uses 20 percent of all the oxygen you take in—using three times as much oxygen as body muscle cells. It grabs 20 percent of all the energy that is generated, using twice the energy of any other body cells, even though the brain accounts for only about 2 percent of the total body weight. Without the mitochondria, the powerhouse of the cells, you would soon be history.