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Classical examples of polarized cells are described below, including epithelial cells with apical-basal polarity, neurons in which signals propagate in one direction from dendrites to axons, and migrating cells. Furthermore, cell polarity is important during many types of asymmetric cell division to set up functional asymmetries between ...
A polar molecule has a net dipole as a result of the opposing charges (i.e. having partial positive and partial negative charges) from polar bonds arranged asymmetrically. Water (H 2 O) is an example of a polar molecule since it has a slight positive charge on one side and a slight negative charge on the other. The dipoles do not cancel out ...
How epithelial cells generate and maintain polarity remains unclear, but certain molecules have been found to play a key role. A variety of molecules are located at the apical membrane , but only a few key molecules act as determinants that are required to maintain the identity of the apical membrane and, thus, epithelial polarity.
Polarity (projective geometry), in mathematics, a duality of order two; Polarity in embryogenesis, the animal and vegetal poles within a blastula; Cell polarity, differences in the shape, structure, and function of cells; Chemical polarity, in chemistry, a separation of electric charge; Magnetic polarity, north or south poles of a magnet
Plasma membranes exhibit electrochemical polarity through establishment and maintenance of a resting membrane potential. Cells with polarized plasma membranes must buffer and adequately distribute certain ions, such as sodium (Na +), potassium (K +), calcium (Ca 2+), and chloride (Cl-) to establish and maintain this polarity. Integral channel ...
Structure of iodine heptafluoride, an example of a molecule with the pentagonal-bipyramidal coordination geometry. In chemistry, a pentagonal bipyramid is a molecular geometry with one atom at the centre with seven ligands at the corners of a pentagonal bipyramid. A perfect pentagonal bipyramid belongs to the molecular point group D 5h.
In organic chemistry, umpolung (German: [ˈʔʊmˌpoːlʊŋ]) or polarity inversion is the chemical modification of a functional group with the aim of the reversal of polarity of that group. [ 1 ] [ 2 ] This modification allows secondary reactions of this functional group that would otherwise not be possible. [ 3 ]
Water, for example, is strongly cohesive as each molecule may make four hydrogen bonds to other water molecules in a tetrahedral configuration. This results in a relatively strong Coulomb force between molecules. In simple terms, the polarity (a state in which a molecule is oppositely charged on its poles) of water molecules allows them to be ...