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Enantiotopic groups are identical and indistinguishable except in chiral environments. For instance, the CH 2 hydrogens in ethanol (CH 3 CH 2 OH) are normally enantiotopic, but can be made different (diastereotopic) if combined with a chiral center, for instance by conversion to an ester of a chiral carboxylic acid such as lactic acid, or if coordinated to a chiral metal center, or if ...
One example is [Ru(NH 3) 5 (SMeEt)] 2+. The complex cis-VOCl 2 (SMeEt) 2 exists as meso- and a pair of enantiomers. [7] In complexes of thioethers of the type S(CH 2 R) 2 (R ≠ H), the methylene protons are diastereotopic. Examination of the NMR spectra of such complexes reveal that they undergo inversion at sulfur, without dissociation of the ...
From these conclusions about plants and animals, two of the three tenets of cell theory were postulated. 1. All living organisms are composed of one or more cells 2. The cell is the most basic unit of life. Schleiden's theory of free cell formation through crystallization was refuted in the 1850s by Robert Remak, Rudolf Virchow, and Albert ...
Pie charts of typical human body composition by percent of mass, and by percent of atomic composition (atomic percent) Body composition may be analyzed in various ways. This can be done in terms of the chemical elements present, or by molecular structure e.g., water , protein , fats (or lipids ), hydroxyapatite (in bones), carbohydrates (such ...
Even though they share the same molar weight, glucose is more stable than galactose. This difference in stability causes galactose to be absorbed slightly faster than glucose in human body. [4] [5] Diastereoselectivity is the preference for the formation of one or more than one diastereomer over the other in an organic reaction.
An example of a proton pump that is not electrogenic, is the proton/potassium pump of the gastric mucosa which catalyzes a balanced exchange of protons and potassium ions. [citation needed] The combined transmembrane gradient of protons and charges created by proton pumps is called an electrochemical gradient.
In medicine, proton therapy, or proton radiotherapy, is a type of particle therapy that uses a beam of protons to irradiate diseased tissue, most often to treat cancer.The chief advantage of proton therapy over other types of external beam radiotherapy is that the dose of protons is deposited over a narrow range of depth; hence in minimal entry, exit, or scattered radiation dose to healthy ...
Donnan equilibrium across a cell membrane (schematic). The Gibbs–Donnan effect (also known as the Donnan's effect, Donnan law, Donnan equilibrium, or Gibbs–Donnan equilibrium) is a name for the behaviour of charged particles near a semi-permeable membrane that sometimes fail to distribute evenly across the two sides of the membrane. [1]