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Unformatted text preview: BISC 220 NOTES January 14, 2009-- structure and function correlate well; molecules and receptors.-- the interaction with the environment, as in molecules in cells.-- Reductionist: cell biology-- cellular functions; cells to biomolecules; from molecules to atoms.-- emergent properties = a collection of smaller items-- biological organisms are chemical systems; similar chemistry of all living organisms.-- energetics (define)-- emergent properties of Na and Cl-- chlorine gas can kill! It destroys the alveoli in the lungs, and they cannot be replaced; the capillaries break and the person drowns in his/her own blood.--- but know that Na and Cl are indeed required for life, from bacteria to us! Chemistry in biological systems:--> C, H, O, N, P, S-- also, trace elements such as I and Mg.-- organic chemistry: originally molecules of natural origin; now usually taken to mean molecules containing C-- reactive groups: hydroxyl, amino, etc.-- trace elements are required by an organism but only in minute quantities.-- many trace elements, like Fe, are required by all organisms.-- (ex.) a daily intake of 0.15 mg of iodine is required for normal activity of the human thyroid gland.-- methane molecule (CH4) has all 4 hybrid orbitals shared an dhas hydrogen nuclei at the corners of the tetrahedron.-- define electronegativity = attraction of an atom for the electros of a covalent bond; strongly electronegative atoms attempt to pull the shared electrons toward themselves.-- polarity = difference in electronegativity; if its equal electronegativity, it is nopolar (H2, and also methane, CH4); unequal electronegativity, its polar (such as H2O). Weak chemical bonds are important!-- within a cell, weak, brief bonds between molecules are important to a variety of processes.-- signal molecules from one neuron use weak bonds to bind briefly to receptor molecules on the surface of a receiving neuron.-- weak interactions include ionic bonds (weak in water), hydrogen bonds, and van der Waals interactions.--- 1 hundred billion by 20,000 neurons communicate (?? check #) _______________________________________________________________________ Jan. 16, 2009-- Hydrogen bonds form when a hydrogen atom that is already covalently bonded to a strongly electronegative atom is attracted to another strongly electronegative atom.-- consider ammonia (NH3) and water: the electronegative atoms oxygen and nitrogen; so hydrogen bonds from water to the nitrogen on ammonia.----------------> our entire genetic makeup depends on hydrogen bonding!!!!!-- a molecules biological function is related to its shape; the shape of a molecule is determined by the arrangement of atoms in the molecule, and the attraction of these atoms for one another and for the solvent....
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