Wednesday, October 27, 2010



4 major types of molecules:
2.) Lipids
4.) Nucleic Acids
Insoluble in water-dont dissolve
     Long chains of repeating CH2 units
     Renders molecule non polar

Types of Lipids:All non polar
Type                                                  Organismal Use                                                                      Human Uses
*Fats                                             Long term energy storage & thermal insulation in animals               Butter, lard
*Oils                                              Long term energy storage in plants and their seeds                        Cooking oils
*Phospholipids                               Component of plasma membrane                                                  No-stick pan spray
*Steroids                                       Component of plasma membrane; hormones                                  Medicines
*Waxes                                          Wear resistance; retain water                                                       Candles, polishes

     Long term energy storage
     Backbone of one glycerol molecule
      -Three carbon alcohol
      -Each has an OH group
     Three fatty acids attached to each glycerol molecule
      -Long hydrocarbon chain
      -Saturated- no double bonds between carbons
      -Unsaturated- >_ 1 double bonds between carbons
      -Carboxylic acid at one end
      -Carboxylic acide connects to -OH on glycerol in dehydration reaction
         Unsaturated- Corn, Corn Oil-double bonds "missing hydrogens" Saturated- Milk, Butter-hydrogens
     Derived from triglycerides
     Two fatty acids attached instead of three
     Third fatty acid replace by phosphate group
      -The fatty acids are non polar and hydrophobic
      -The phosphate group is polar and hydrophilic
     Molecules self arrange when placed in water
      -Polar phosphate "heads" next to water
      -Non polar fatty acids "tails" overlap and exclude water
      -Spontaneously form double layer and a sphere

Steroids & Waxes
     Cholesterol, testosterone, estrogen
     Skeletons of four fused carbon rings
     Long-chain fatty acids bonded to a long chain alcohol
      High Melting point
      Resistant to degradation

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