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.
This means that, on a full frame camera, any lens with a focal length of less than 35mm is considered to be a wide-angle lens. The lower the focal length, the wider the field of view and thus, the wider the lens. Any lens with a focal length lower than 24mm may be referred to as an ultra wide-angle lens. On a crop sensor camera, wide-angle lenses start at a focal length of around 24mm and go down from there.