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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]
The oxygen-evolving complex is the site of water oxidation. 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 ...
Oxidation state is an important index to evaluate the charge distribution within molecules. [2] The most common definition of oxidation state was established by IUPAC, [3] which let the atom with higher electronegativity takes all the bonding electrons and calculated the difference between the number of electrons and protons around each atom to assign the oxidation states.
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 ...
The complex is a large integral membrane protein composed of several metal prosthetic sites and 13 [2] protein subunits in mammals. In mammals, ten subunits are nuclear in origin, and three are synthesized in the mitochondria. The complex contains two hemes, a cytochrome a and cytochrome a 3, and two copper centers, the Cu A and Cu B centers. [3]
The US Institute of Medicine (IOM) established Recommended Dietary Allowances (RDAs) for calcium in 1997 and updated those values in 2011. [6] See table. The European Food Safety Authority (EFSA) uses the term Population Reference Intake (PRIs) instead of RDAs and sets slightly different numbers: ages 4–10 800 mg, ages 11–17 1150 mg, ages 18–24 1000 mg, and >25 years 950 mg. [10]
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]
The resting concentration of Ca 2+ in the cytoplasm is normally maintained around 100 nM.This is 20,000- to 100,000-fold lower than typical extracellular concentration. [1] [2] To maintain this low concentration, Ca 2+ is actively pumped from the cytosol to the extracellular space, the endoplasmic reticulum (ER), and sometimes into the mitochondria.