BLG 143 Final: BLG143 Chapter6 Exam Notes
31 Jan 2015
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Chapter 6: lipids, membranes and the first cells. Plasma membrane: selective barrier, keeps damaging compounds out and allows entry of needed compounds. Separates cell from external environment; life from non-life. Lipid: carbon-containing compounds that are largely non polar and hydrophobic. Hydrocarbon: molecules that contain only c and h. Non-polar b/c of equal sharing of electrons. Fats/ triglycerides: composed of three fatty acids and 1 glycerol. Fatty acid: hydrocarbon chain bonded to carboxyl group. Form dehydration rxn. between oh group of glycerol and cooh group of fatty acid joined by ester linkage. Steroid: family of lipids distinguished by four-ring structure ex. Has hydrophilic oh group and hydrocarbon tail formed of isoprene subunits. Phospholipids: glycerol linked to phosphate group (po43-) and to either two chains of isoprene (archaea) or to two fatty acids (bacteria and eukarya) Do not dissolve in water; form either micelles or phospholipid bilayers (spontaneously: no energy input b/c more stable)
