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  2. Oxygen - Wikipedia

    en.wikipedia.org/wiki/Oxygen

    2 combines with atomic oxygen made by the splitting of O 2 by ultraviolet (UV) radiation. [22] Since ozone absorbs strongly in the UV region of the spectrum, the ozone layer of the upper atmosphere functions as a protective radiation shield for the planet. [22] Near the Earth's surface, it is a pollutant formed as a by-product of automobile ...

  3. Great Oxidation Event - Wikipedia

    en.wikipedia.org/wiki/Great_Oxidation_Event

    The rise in oxygen content was not linear: instead, there was a rise in oxygen content around 2.3 Ga, followed by a drop around 2.1 Ga. This rise in oxygen is called the Lomagundi-Jatuli event, Lomagundi event, [98] [99] or Lomagundi-Jatuli excursion [100] (named for a district of Southern Rhodesia) and the time period has been termed Jatulian ...

  4. Allotropes of oxygen - Wikipedia

    en.wikipedia.org/wiki/Allotropes_of_oxygen

    Singlet oxygen is the common name used for the two metastable states of molecular oxygen (O 2) with higher energy than the ground state triplet oxygen. Because of the differences in their electron shells, singlet oxygen has different chemical and physical properties than triplet oxygen, including absorbing and emitting light at different ...

  5. Geological history of oxygen - Wikipedia

    en.wikipedia.org/wiki/Geological_history_of_oxygen

    Photosynthetic prokaryotic organisms that produced O 2 as a byproduct lived long before the first build-up of free oxygen in the atmosphere, [5] perhaps as early as 3.5 billion years ago. The oxygen cyanobacteria produced would have been rapidly removed from the oceans by weathering of reducing minerals, [ citation needed ] most notably ferrous ...

  6. Oxygen evolution - Wikipedia

    en.wikipedia.org/wiki/Oxygen_evolution

    Oxygen evolution is the chemical process of generating elemental diatomic oxygen (O 2) by a chemical reaction, usually from water, the most abundant oxide compound in the universe. Oxygen evolution on Earth is effected by biotic oxygenic photosynthesis , photodissociation , hydroelectrolysis , and thermal decomposition of various oxides and ...

  7. Cellular respiration - Wikipedia

    en.wikipedia.org/wiki/Cellular_respiration

    Aerobic respiration requires oxygen (O 2) in order to create ATP.Although carbohydrates, fats and proteins are consumed as reactants, aerobic respiration is the preferred method of pyruvate production in glycolysis, and requires pyruvate to the mitochondria in order to be oxidized by the citric acid cycle.

  8. O2 - Wikipedia

    en.wikipedia.org/wiki/O2

    O 2 or dioxygen, the common allotrope of the chemical element oxygen; O 2−, the ion oxide; O − 2, the ion superoxide; O + 2, the ion dioxygenyl; O 2+, doubly ionized oxygen; O(2), the 2-dimensional orthogonal group in group theory; O2, an EEG electrode site according to the 10–20 system; SGI O2, a Unix workstation computer

  9. Oxidative phosphorylation - Wikipedia

    en.wikipedia.org/wiki/Oxidative_phosphorylation

    Oxidative phosphorylation uses these molecules and O 2 to produce ATP, which is used throughout the cell whenever energy is needed. During oxidative phosphorylation, electrons are transferred from the electron donors to a series of electron acceptors in a series of redox reactions ending in oxygen, whose reaction releases half of the total ...