COMPOUND LIPIDS

• Compound lipids


  Esters of fatty acids and alcohols in combination with other compounds
• Types of compound lipids

  • Phospholipids
  • Glycolipids
• Phospholipids


  • Fatlike compounds containing alcohol, phosphoric acid and a nitrogen base
• Types of phospholipids

  • Glycerophospholipids
  • Sphingophospholipids
• Glycerophospholipids


  Glycerol + N-base + H3PO4
• Sphingophospholipids


  Sphingosine + N-base + H3PO4
• Glycolipids


  Compounds containing a fatty acid, a carbohydrate, a complex alcohol, and nitrogen but no phosphorous
• Glycerophospholipids


  • Fatlike substances containing glycerol, two fatty acids, nitrogen base and phosphoric acid
• Glycerophospholipids


  • Lecithin (phosphatidyl choline)
  • Cephalin (phosphatidyl ethanolamine)
• Lecithin


  Glycerol + 2 fatty acids + H3PO4 + N-base, choline
• Cephalin


  Glycerol + 2 fatty acids + H3PO4 + N-base, ethanolamine
• Sphingophospholipids


  • Do not contain glycerol
  • Contains an amino alcohol, sphingosine
  • Has one fatty acid group + H3PO4 + N-base, choline
• Sphingophospholipids


  • Sphingomyelin
• Glycolipids


  • Contain one or more polysaccharides
• Glycolipids


  • Cerebroside
  • Ganglioside
• Ceramide

  Composed of sphingosine + fatty acid
• Cerebroside


  Found in the cell membranes of muscle and nervous tissues
• Galactocerebrosides


  Main glycosphingolipid in the brain
• Steroids


  • Composed of three cyclohexane rings and one cyclopentane ring
  • Secreted by the endocrine glands
  • Hormone is a molecule that is synthesized in one part of an organism which produce a response at a different site
  • Hydrophobic, insoluble in water
• Types of steroids

  • Sex hormones
  • Adrenal cortical steroids
• Types of sex hormones

  • Estrogen
  • Progestins
• Estradiol and estrone


  Estrogens synthesized in the ovaries
• Progesterone


  A progestin "pregnancy hormone"
• Androgens


  Male sex hormones
• Cholesterol


  • Most abundant sterol (steroid + alcohol) in the human body
  • Synthesized in the liver and can be found in all body tissues
  • A component of cell membranes and a precursor for other steroid-based lipids
  • Widely distributed in all cells of the body especially the nervous tissues
  • It occurs in animal fats but not in plant fats
  • It serves as the starting material for the synthesis all other steroids and vitamin D (good for immune system)
  • Serves as a plasma membrane component in all animal cells – in RBC
  • Serves as a raw material for the synthesis of sex and adrenocorticoid hormones, vitamin D and bile salts
• Cholesterol structure

  • Insoluble in water
  • Travels in the blood stream in the form of lipoproteins
  • Different types of cholesterol found in the blood cells are triglycerides, LDL, HDL, and VLDL
  • Synthesized in the liver
  • Insoluble in the aqueous mixture of the blood, transported from the liver to tissues
  • Combines with phospholipids and proteins to form particles called lipoproteins
  • Too much LDL can cause clog
• Biological wax

  • Monoester of a long-chain fatty acid and a long-chain alcohol
  • Fatty acids in waxes are saturated (14 to 36 carbon atoms)
  • Alcohols may be saturated or unsaturated and may contain from 16 to 30 carbon atoms
• Biological waxes

  • Carnauba wax
  • Beeswax
  • Lanolin
• Human ear wax


  Not a true biological wax, it is a mixture of triacylglycerols, phospholipids, esters of cholesterol
• Paraffin waxes

  Mineral waxes, a mixture of long-chain alkanes (candles, waterproof coating for paper products)