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The oxygen cycle is the biogeochemical cycle of oxygen atoms between different oxidation states in ions, oxides, and molecules through redox reactions within and between the spheres/reservoirs of the planet Earth. [1] The word oxygen in the literature typically refers to the most common oxygen allotrope, elemental/diatomic oxygen (O 2), as it ...
Mars Oxygen ISRU Experiment. The Mars Oxygen In-Situ Resource Utilization Experiment (MOXIE) [1] was a technology demonstration on the NASA Mars 2020 rover Perseverance investigating the production of oxygen on Mars. [2] On April 20, 2021, MOXIE produced oxygen from carbon dioxide in the Martian atmosphere by using solid oxide electrolysis.
Oxygen is the third most abundant chemical element in the universe, after hydrogen and helium.[67] About 0.9% of the Sun's mass is oxygen.[18] Oxygen constitutes 49.2% of the Earth's crustby mass[68]as part of oxide compounds such as silicon dioxideand is the most abundant element by mass in the Earth's crust.
In chemistry and biology, reactive oxygen species (ROS) are highly reactive chemicals formed from diatomic oxygen (O2), water, and hydrogen peroxide. Some prominent ROS are hydroperoxide (O 2 H), superoxide (O 2-), [ 1 ] hydroxyl radical (OH.), and singlet oxygen. [ 2 ] ROS are pervasive because they are readily produced from O 2, which is ...
Methane biochemistry (Azotosome) Non-water solvents. Methane-based life. Methane (CH 4) is relatively abundant in the solar system and the universe, and is known to exist in liquid form on Titan, the largest moon of Saturn. Though highly unlikely, it is considered to be possible for Titan to harbor life.
Solid oxygen. This article is about the solid phase of elemental oxygen. For solids used as a source of oxygen or as an oxidizer, see Oxidizing agent. Solid oxygen forms at normal atmospheric pressure at a temperature below 54.36 K (−218.79 °C, −361.82 °F). Solid oxygen O 2, like liquid oxygen, is a clear substance with a light sky-blue ...
Oxygen evolution. Oxygen evolution is the process of generating molecular oxygen (O 2) by a chemical reaction, usually from water. Oxygen evolution from water is effected by oxygenic photosynthesis, electrolysis of water, and thermal decomposition of various oxides. The biological process supports aerobic life.
Photosystem II (or water-plastoquinone oxidoreductase) is the first protein complex in the light-dependent reactions of oxygenic photosynthesis. It is located in the thylakoid membrane of plants, algae, and cyanobacteria. Within the photosystem, enzymes capture photons of light to energize electrons that are then transferred through a variety ...