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Macromolecules

Macromolecules. Overview: The Molecules of Life Another level in the hierarchy of biological organization is reached when small organic molecules are joined together. Figure 5.1. Macromolecules Are large molecules composed of smaller molecules Are complex in their structures.

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Macromolecules

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  1. Macromolecules

  2. Overview: The Molecules of Life • Another level in the hierarchy of biological organization is reached when small organic molecules are joined together

  3. Figure 5.1 • Macromolecules • Are large molecules composed of smaller molecules • Are complex in their structures

  4. Most macromolecules are polymers, built from monomers. • A polymer • Is a long molecule consisting of many similar building blocks called monomers

  5. 1 HO H 3 2 H HO Unlinked monomer Short polymer Dehydration removes a watermolecule, forming a new bond H2O 1 2 3 4 HO H Longer polymer (a) Dehydration reaction in the synthesis of a polymer The Synthesis and Breakdown of Polymers • Monomers form larger molecules by condensation reactions called dehydration synthesis

  6. 1 3 HO 4 2 H Hydrolysis adds a watermolecule, breaking a bond H2O 1 2 H HO 3 H HO (b) Hydrolysis of a polymer • Polymers can disassemble by hydrolysis

  7. The Diversity of Polymers • Each class of polymer is formed from a specific set of monomers • Although organisms share the same limited number of monomer types, each organism is unique based on the arrangement of monomers into polymers • An immense variety of polymers can be built from a small set of monomers 1 3 2 H HO

  8. Four Main Types • Carbohydrates • “Lipids” • Proteins • Nucleic acids

  9. Carbohydrates

  10. Carbohydrates

  11. Atoms • C, H, and O • often a 1:2:1 ratio

  12. Functions • Energy • Structure

  13. Types • Monosaccharide = monomers, simple sugars • Disaccharide = 2 sugars • Polysaccharide =Many sugars

  14. Monosaccharide Examples

  15. Glucose

  16. Fructose

  17. Deoxyribose

  18. galactose

  19. Disaccharide Examples

  20. Glucose + Galactose = Lactose

  21. glucose + glucose = maltose

  22. Glucose + fructose = sucrose

  23. Polysaccharide Examples • Starch – energy storage in plants • Cellulose – cell walls of plants • Glycogen – energy storage in animals • Chitin – cell walls of fungi and animal exoskeletons

  24. chitin cellulose

  25. enzyme enzyme Digesting starch vs. cellulose starcheasy todigest cellulosehard todigest

  26. Cellulose • Most abundant organic compound on Earth • herbivores have evolved a mechanism to digest cellulose • most carnivores have not • that’s why they eat meat to get their energy & nutrients • cellulose = undigestible roughage But it tasteslike hay!Who can liveon this stuff?!

  27. Cow can digest cellulose well; no need to eat other sugars Gorilla can’t digest cellulose well; must add another sugar source, like fruit to diet

  28. Helpful bacteria • How can herbivores digest cellulose so well? • BACTERIA live in their digestive systems & help digest cellulose-rich (grass) meals Coprophage Ruminants

  29. Lipids

  30. Lipids: Fats & Oils

  31. Atoms • C, H, and O • (not a particular ratio, heavy on the hydrocarbons) • Insoluble in water

  32. Lipid Functions • Energy • Insulation • Cellular communication • Cell membrane structure • Protection

  33. blubber

  34. hormones for communication

  35. cell membranes

  36. Examples (“polymers”) • Fats • Oils • Waxes • Steroids • Phospholipids

  37. Fat tissue

  38. oils

  39. Notice the light reflecting off the wax covering of the leaves!

  40. steriod hormones

  41. Monomer – no true monomers • Fat molecules are composed of: • one glycerol molecule • three triglyceride (Fatty acids) molecules =triacylglycerol

  42. enzyme enzyme enzyme H2O H2O H2O H2O Dehydration synthesis dehydration synthesis

  43. Fats store energy • Long HC chain • polar or non-polar? • hydrophilic or hydrophobic? • Function: • energy storage • concentrated • all H-C! • 2x carbohydrates • cushion organs • insulates body • think whale blubber!

  44. Fats can be • Saturated • Single bonds between carbons • Contains maximum # of H • Solid at room temperature • Unsaturated • Double bonds between carbons • Lacking some H • Liquid at room temperature

  45. Saturated fats • All C bonded to H • No C=C double bonds • long, straight chain • most animal fats • solid at room temp. • contributes to cardiovascular disease (atherosclerosis) = plaque deposits

  46. Unsaturated fats • C=C double bonds in the fatty acids • plant & fish fats • vegetable oils • liquid at room temperature • the kinks made by doublebonded C prevent the molecules from packing tightly together

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