A mitochondrion is a double-membrane-bound organelle found in most eukaryotic organisms. Mitochondria use aerobic respiration to generate most of the cell's supply of adenosine triphosphate (ATP), which is subsequently used throughout the cell as a source of chemical energy. They were discovered by Albert von Kölliker in 1857 in the voluntary muscles of insects. The term mitochondrion was coined by Carl Benda in 1898. The mitochondrion is popularly nicknamed the "powerhouse of the cell", a phrase coined by Philip Siekevitz in a 1957 article of the same name.