BIOL 141 Chapter Notes - Chapter 6: Polyunsaturated Fat, Protein Structure, Amphiphile
27 Oct 2017
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Chapter 6: lipids, membranes, and the first cells. Plasma/cell membrane: a membrane that surrounds a cell, separating it from the external environment and selectively regulating passage of molecules and ions into and out of the cell. Allows entry to substances needed by the cell. Sequesters the appropriate chemicals in an enclosed area. Allows chemical reactions necessary for life to occur more efficiently. Lipid: any organic substance that is hydrophobic and nonpolar; include fatty acids, fats, oils, waxes, steroids, and phospholipids. Unsaturated hydrocarbons contain carbon-carbon double bonds and saturated hydrocarbons to not. Hydrocarbon: an organic molecule that contains only hydrogen and carbon atoms. Nonpolar because the electrons are shared equally in c h bonds because of their similar electronegativity"s. Do not form partial charges, making them nonpolar and hydrophobic. Lipids are mostly hydrophobic due to their hydrocarbons. Typically contain 14-20 carbon atoms in their long hydrocarbon tails.
