lipids

• Lipids


  Another important class of nutrients that include fatty acids, phospholipids, steroids, and cholesterol
• Lipids


  • They are insoluble in water but are soluble in nonpolar solvents
  • They contain larger amount of carbon and hydrogen atoms than oxygen atoms
• Types of lipids

  • Simple lipids (cholesterol, don't have fatty acids)
  • Complex lipids (triglycerides, phospholipid & waxes)
• Fatty acids


  Consist of a long, hydrophobic nonpolar hydrocarbon "tail" and a hydrophilic polar carboxylic acid functional group at the "head"
• Types of fatty acids

  • Saturated fatty acids (have no carbon-carbon double bonds, solid at room temp)
  • Unsaturated fatty acids (contain one or more double bonds, exist as liquids at room temperature)
• Saturated fatty acid

  • Lauric acid
• Unsaturated fatty acid

  • Oleic acid
• Triglycerides


  Most abundant class of lipids in plants & animals, composed of glycerol backbone and fatty acids, fats (animal origin, solid triglycerides), oils (plant origin, liquid triglycerides)
• Phospholipids


  Fundamental building blocks of cellular membranes, consist of hydrophilic heads (lover water) and hydrophobic tails (hates water), form a bilayer where the hydrophobic tails point towards each other on the interior and only the hydrophilic heads are exposed to the water
• Waxes


  Composed of fatty acids combined with a much longer alcohol molecule, used as polishers, ointments, and to protect the surfaces of some leaves
• Steroids


  Simple lipids that have a backbone structure consisting of four fixed carbon rings, example is cholesterol which is the most abundant steroid in animal tissues and helps regulate fluidity in cell membranes
• Types of cholesterol

  • High Density Lipoprotein (good)
  • Low Density Lipoprotein (bad)
• Lipids


  • Act as chemical messengers
  • Provide storage and provision of energy
• Lipids are components of membrane structure and regulate the membrane permeability
• Lipids protect the internal organs and serve as insulating materials