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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 ...
This center, below and to the left of the pair in the diagram, contains four manganese ions, a calcium ion, a chloride ion, and a tyrosine residue. Manganese is adept at these reactions because it is capable of existing in four oxidation states: Mn 2+, Mn 3+, Mn 4+ and Mn 5+. Manganese also forms strong bonds with oxygen-containing molecules ...
Manganese dioxide also catalyses the decomposition of hydrogen peroxide to oxygen and water: 2 H 2 O 2 → 2 H 2 O + O 2. Manganese dioxide decomposes above about 530 °C to manganese(III) oxide and oxygen. At temperatures close to 1000 °C, the mixed-valence compound Mn 3 O 4 forms. Higher temperatures give MnO, which is reduced only with ...
A plant cell wall was first observed and named (simply as a "wall") by Robert Hooke in 1665. [3] However, "the dead excrusion product of the living protoplast" was forgotten, for almost three centuries, being the subject of scientific interest mainly as a resource for industrial processing or in relation to animal or human health.
Calvin cycle. The Calvin cycle, Calvin–Benson–Bassham (CBB) cycle, reductive pentose phosphate cycle (RPP cycle) or C3 cycle is a series of biochemical redox reactions that take place in the stroma of chloroplast in photosynthetic organisms. The cycle was discovered in 1950 by Melvin Calvin, James Bassham, and Andrew Benson at the ...
Diamond and graphite are two allotropes of carbon: pure forms of the same element that differ in crystalline structure.. Allotropy or allotropism (from Ancient Greek ἄλλος (allos) 'other' and τρόπος (tropos) 'manner, form') is the property of some chemical elements to exist in two or more different forms, in the same physical state, known as allotropes of the elements.
Hill reaction. Plant cells with visible chloroplasts (from a moss, Plagiomnium affine) The Hill reaction is the light-driven transfer of electrons from water to Hill reagents (non-physiological oxidants) in a direction against the chemical potential gradient as part of photosynthesis. Robin Hill discovered the reaction in 1937.
One of the more studied manganese oxide-based cathodes is LiMn 2 O 4, a cation ordered member of the spinel structural family (space group Fd3m). In addition to containing inexpensive materials, the three-dimensional structure of LiMn 2 O 4 lends itself to high rate capability by providing a well connected framework for the insertion and de ...