Most eukaryotic cells have mitochondria, which produce ATP from products of the citric acid cycle, fatty acid oxidation, and amino acid oxidation. At the mitochondrial inner membrane, electrons from NADH and succinate pass through the electron transport chain to oxygen, which is reduced to water.
The maximum diameter of the lens opening is referred to as its maximum aperture or minimum f-number. The minimum f-number is the smallest f-number that can be selected with the lens. The maximum aperture varies from lens to lens and is included in the lens model name.
In exceptional circumstances lenses can have even wider apertures with f-numbers smaller than 1.0; see lens speed: fast lenses for a detailed list. For instance, in photography, both the current Leica Noctilux-M 50mm ASPH and a 1960s-era Canon 50mm rangefinder lens have a maximum aperture of f /0.95.