Lipids

• Lipids: a diverse group of hydrophobic molecules.
• All lipids have little or no affinity for water.
• Lipids have lots of Carbon-Hydrogen bonds, but little oxygen.
• Lipids have carbon, oxygen, & hydrogen.
• Lipids are hydrophobic due to their hydrocarbon makeup. They form non-polar covalent bonds.
• Fats, phospholipids, & steroids are the most biologically important lipids.
• The functions of lipids are long term energy (in the bonds), insulation, hormones (not all, but many), cell membrane.
• Triglyceride: three fatty acids joined to glycerol by an ester linkage.
• Glycerol: three carbon alcohol with a hydroxyl (OH) group attached to each carbon.
• Fatty Acid: consists of a carboxyl (COOH) group attached to a long carbon skeleton.
• Saturated Fatty Acid: maximum number of hydrogen atoms possible & no double bonds.
• Saturated Fatty Acids take longer to break down.
• Saturated Fatty Acids are solid at room temperature and mainly animal fat.
• Saturated Fatty Acid

  
• Unsaturated Fatty Acids: one or more double bonds.
• Unsaturated Fatty Acids are liquid at room temperature, easier to break down, and mainly plants & fish fat.
• Unsaturated Fatty Acid

  
• A diet rich in saturated fats may contribute to cardiovascular disease through plaque deposits.
• Hydrogenation: the process of converting unsaturated fats to saturated fats by adding hydrogen, resulting in trans fat.
• Phospholipids are two fatty acids, phosphate group, & glycerol.
• The fatty acids tails in a phospholipid are hydrophobic.
• The phosphate group & glycerol in a phospholipid form a hydrophilic 'head'.
• Steroids: lipids characterized by a carbon skeleton consisting of 4 FUSED rings.
• Phospholipid Picture.

  
• Steroid Picture.