Mitochondrial biology is the study of mitochondria, the energy-producing organelles found in most eukaryotic cells. These structures convert nutrients into adenosine triphosphate (ATP), the primary energy currency of the cell. Mitochondria also play roles in regulating metabolism, cell growth, and apoptosis, or programmed cell death. Mitochondria have their own DNA, distinct from the nuclear DNA found in the cell's nucleus. This mitochondrial DNA (mtDNA) is inherited maternally and can provide insights into evolutionary biology and human ancestry. Research in mitochondrial biology is crucial for understanding various diseases, including metabolic disorders and neurodegenerative conditions.