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It is a metallo-oxo cluster comprising four manganese ions (in oxidation states ranging from +3 to +4) [6] and one divalent calcium ion. When it oxidizes water, producing oxygen gas and protons, it sequentially delivers the four electrons from water to a tyrosine (D1-Y161) sidechain and then to P680 itself.
Calcium peroxide or calcium dioxide is the inorganic compound with the formula CaO 2. It is the peroxide (O 2 2−) salt of Ca 2+. Commercial samples can be yellowish, but the pure compound is white. It is almost insoluble in water. [3]
X-ray crystal structure of the Mn 4 O 5 Ca core of the oxygen evolving complex of Photosystem II at a resolution of 1.9 Å. [2] The oxygen-evolving complex (OEC), also known as the water-splitting complex, is a water-oxidizing enzyme involved in the photo-oxidation of water during the light reactions of photosynthesis. [3]
Its usage varies from about 30 to 50 kilograms (65–110 lb) per ton of steel. The quicklime neutralizes the acidic oxides, SiO 2, Al 2 O 3, and Fe 2 O 3, to produce a basic molten slag. [10] Ground quicklime is used in the production of aerated concrete such as blocks with densities of ca. 0.6–1.0 g/cm 3 (9.8–16.4 g/cu in). [10]
Condensation of chromatin is a vital step in cell division, allowing cells to equally distribute chromosomes to the daughter cells. Recent work has suggested that Ca 2+ is required for enabling chromatin condensation in prometaphase. Calcium was found to concentrate on condensed DNA to much higher levels compared to normal cytosolic calcium ...
Mitotic cell division enables sexually reproducing organisms to develop from the one-celled zygote, which itself is produced by fusion of two gametes, each having been produced by meiotic cell division. [5] [6] After growth from the zygote to the adult, cell division by mitosis allows for continual construction and repair of the organism. [7]
2 is no longer zero as with the standard hydrogen electrode (SHE) at 1 M H + (pH = 0) in classical electrochemistry, but that = versus the standard hydrogen electrode (SHE). [2] The same also applies for the reduction potential of oxygen: O 2 + 4 H + + 4 e − ⇌ 2 H 2 O
The cell cycle is a series of complex, ordered, sequential events that control how a single cell divides into two cells, and involves several different phases. The phases include the G1 and G2 phases, DNA replication or S phase, and the actual process of cell division, mitosis or M phase. [1]