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Chapter 19

Chapter 19. Lipids. Goals. Know and draw lipids Understand and identify steroids and vitamins Describe biological membranes and cell transport processes. Lipids. Efficient storage of energy Found in. Lipid Varieties. Triacylglycerol Glycerophospholipids, cholesterol Bile salts.

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Chapter 19

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  1. Chapter 19 Lipids

  2. Goals • Know and draw lipids • Understand and identify steroids and vitamins • Describe biological membranes and cell transport processes.

  3. Lipids • Efficient storage of energy • Found in

  4. Lipid Varieties • Triacylglycerol • Glycerophospholipids, cholesterol • Bile salts

  5. Classification of Lipids • Based on Solubility behavior • Amphipathic

  6. Hydrolyzable • Can be split apart • Contain • Saponification

  7. Nonhydrolyzable • No • No • Nonsaponifiable lipids

  8. Fatty Acids • Long, straight chain • Saturated • Unsaturated

  9. Physical Properties • Depend on number of C • Solubility • Melting point

  10. Triacylglycerol • Triglycerides • Triesters of glycerol • Simple – all • Complex – different

  11. Triglycerides • Animal fat: • Cis bonds have similar effect on mp as in fatty acids • All are

  12. Reactions of Triglycerides • Hydrolysis • Acid catalyzed yields • Basic catalyzed (saponification) yields

  13. Digestion of Triglycerides • Too big to pass through intestinal membranes • Hydrolyzed by • Packaged into • Hydrolyzed • Stored in

  14. Catalytic Hydrogenation • Addition of Hydrogen to • Hardens the triglyceride • Margarine

  15. Rancidity • Development of unpleasant odor

  16. Waxes • Protective functions • Structural – • Energy storage – • Esters of fatty acids and long chain alcohols • Commercial uses

  17. Amphipathic hydrolyzables • Glycerophospholipids • Sphingolipids • Both have hydrophilic and hydrophobic groups • Allows for insertion into cell membrane

  18. Glycerophospholipid • Esterification of glycerol with two fatty acids and one phosphoric acid • See Table 19.3 p. 569 • Made with choline = lecithin

  19. Sphingolipids • Based on sphingosine • Two types

  20. Uses • Cell walls • Contain oligosaccharides – • Deficiencies

  21. Steroids • Nonhydrolyzable lipids with base steroid ring structure • Includes

  22. Hormones • Synthesized in and secreted by the • Regulate • Very effective at low concentrations (10-12-10-9M)

  23. Adrenocortical hormones • Cortisol • Aldosterone

  24. Sex Hormones • Produced in gonads • Female • Male • Contraceptives page 573

  25. Bile Salts • Carboxylate salt • Essential for • Secreted into the small intestine after

  26. Eicosanoids • Leukotrienes • Prostaglandins • Thromboxanes

  27. Vitamins • Water soluble: • Fat soluble: • D is technically a steroid hormone • Deficiencies cause problems • See box 19.4 p 577

  28. Biological Membranes • Compartmentalization • Selective • Cell recognition • Communication • Maintain ion concentrations against gradient

  29. Membrane structure • Lipid bilayer • Amphipathic lipids • Assorted proteins • Integral • peripheral • Sugars for recognition • Fluid mosaic model p. 579

  30. Transport • Simple - diffusion along a gradient • Facilitated – uses transporters • Active – uses a pump • Na+/K+ pump uses energy from hydrolysis of ATP to ADP to work • Exocytosis – exporting material • Endocytosis - importing

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