The cellular organelle responsible for energy production is the mitochondrion. Often termed the "powerhouse of the cell," mitochondria convert nutrients into adenosine triphosphate (ATP), the primary energy currency of the cell, through the process of cellular respiration. This process involves breaking down glucose in the presence of oxygen to produce ATP, along with carbon dioxide and water as byproducts. Mitochondria also have their own DNA and are involved in various metabolic processes, playing a vital role in energy metabolism and overall cellular function.