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  2. Ion - Wikipedia

    en.wikipedia.org/wiki/Ion

    The net charge of an ion is not zero because its total number of electrons is unequal to its total number of protons. A cation is a positively charged ion with fewer electrons than protons [2] (e.g. K + (potassium ion)) while an anion is a negatively charged ion with more electrons than protons. [3] (e.g. Cl − (chloride ion) and OH − ...

  3. Ion channel - Wikipedia

    en.wikipedia.org/wiki/Ion_channel

    In addition, ion channels are key components in a wide variety of biological processes that involve rapid changes in cells, such as cardiac, skeletal, and smooth muscle contraction, epithelial transport of nutrients and ions, T-cell activation, and pancreatic beta-cell insulin release. In the search for new drugs, ion channels are a frequent ...

  4. DNA photoionization - Wikipedia

    en.wikipedia.org/wiki/DNA_photoionization

    DNA photoionization is the phenomenon according to which ultraviolet radiation absorbed directly by a DNA system (mononucleotide, single or double strand, G-quadruplex…) induces the ejection of electrons, leaving electron holes on the nucleic acid.

  5. Membrane potential - Wikipedia

    en.wikipedia.org/wiki/Membrane_potential

    Facilitated diffusion in cell membranes, showing ion channels and carrier proteins. The resistance of a pure lipid bilayer to the passage of ions across it is very high, but structures embedded in the membrane can greatly enhance ion movement, either actively or passively, via mechanisms called facilitated transport and facilitated diffusion.

  6. Inorganic ions - Wikipedia

    en.wikipedia.org/wiki/Inorganic_ions

    Potassium ion channels play a key role in maintaining the membrane's electric potential. These ion channels are present in many various biological systems. They frequently play a role in regulation of cellular level processes, many of these processes including muscle relaxation, hypertension, insulin secretion etc. [7] Some examples of potassium ion channels within biological systems include K ...

  7. Photoionization - Wikipedia

    en.wikipedia.org/wiki/Photoionization

    This cross section depends on the energy of the photon (proportional to its wavenumber) and the species being considered i.e. it depends on the structure of the molecular species. In the case of molecules, the photoionization cross-section can be estimated by examination of Franck-Condon factors between a ground-state molecule and the target ion.

  8. Ionophore - Wikipedia

    en.wikipedia.org/wiki/Ionophore

    The structure of the complex of sodium (Na +) and the antibiotic monensin A Structure of a potassium complex of a crown ether, a synthetic ionophore-ion complex. Biological activities of metal ion-binding compounds can be changed in response to the increment of the metal concentration, and based on the latter compounds can be classified as "metal ionophores", "metal chelators" or "metal ...

  9. Cell (biology) - Wikipedia

    en.wikipedia.org/wiki/Cell_(biology)

    The cell is the basic structural and functional unit of all forms of life. Every cell consists of cytoplasm enclosed within a membrane; many cells contain organelles, each with a specific function. The term comes from the Latin word cellula meaning 'small room'. Most cells are only visible under a microscope.