Tracing how cells learned to live without oxygen (opens in new tab)

Mitochondria are among the most important structures inside living cells. These tiny compartments help generate the energy that powers not only our bodies, but also the cells of all eukaryotes (i.e., animals, plants, fungi and countless single-celled organisms like amoebae).The origin of mitochondria was one of the most dramatic events in the history of life. More than a billion years ago, a bacterium took up residence inside another cell, eventually becoming part of the cell itself — the mit...