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					Lipids notes
            Four Classes of Organics:
                    2 - Lipids
  •         Insoluble in water
        –    Long chains of repeating CH2 units
        –    Renders molecule nonpolar
   •  Types of Lipids
•Type         •Organismal Uses                        •Human Uses
                     •Long-term energy storage &
•Fats                thermal insulation in animals
                                                      •Butter, lard
                     •Long-term energy storage in
•Oils                plants and their seeds
                                                      •Cooking oils
                     •Component of plasma
•Phospholipids       membrane
                                                      •No-stick pan spray
                     •Component of plasma
•Steroids            membrane; hormones
                                                      •Medicines

•Waxes               •Wear resistance; retain water   •Candles, polishes
Blubber
   Lipids:
Triglyceride
      s
             Types of Lipids:
             Triglycerides (1)
• Triglycerides (Fats)
  – 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 acid connects to –OH on glycerol in
      Triglyceride
from Glycerol and Three
      Fatty Acids
            Types of Lipids:
           Phospholipids (2)
• Phospholipids
• Derived from triglycerides
  – Glycerol backbone
  – Two fatty acids attached instead of three
  – Third fatty acid replaced by phosphate group
     • The fatty acids are nonpolar and hydrophobic
     • The phosphate group is polar and hydrophilic
• Molecules self arrange when placed in
  water
  – Polar phosphate “heads” next to water
Phospholipids Form
   Membranes
         Types of Lipids:
       Steroids & Waxes (3)
• Steroids
  – Cholesterol, testosterone, estrogen
  – Skeletons of four fused carbon rings

• Waxes
  – Long-chain fatty acid bonded to a long-chain
    alcohol
    • High melting point
    • Waterproof
    • Resistant to degradation
Steroid Diversity
Waxes

				
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posted:8/9/2012
language:English
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