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Lecture 5 Sept 9, 2005 MACROMOLECULES #1

Lecture 5 Sept 9, 2005 MACROMOLECULES #1. Carbohydrates. And Lipids. Lecture outline:. - Polymers. Carbohydrates monomers and polymers. - Lipids. Principles of Building Polymers:. biological polymers are built from simple small units called monomers.

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Lecture 5 Sept 9, 2005 MACROMOLECULES #1

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  1. Lecture 5 Sept 9, 2005 MACROMOLECULES #1 Carbohydrates And Lipids

  2. Lecture outline: - Polymers • Carbohydrates • monomers and polymers - Lipids

  3. Principles of Building Polymers: • biological polymers are built from simple small units called monomers • addition of each monomeric unit occurs with the • removal of a water molecule A condensation dehydration reaction • ends are chemically distinct • directionality of synthesis • requires energy input for polymerization; • uses carrier molecules to activate monomers

  4. MODULAR DESIGN SIMPLICITY AND VERSATILITY ASSEMBLY-LINE MENTALITY Don’t have to make every structure from scratch Simplified chemistry, repeating link Dehydration Synthesis

  5. Hydrolysis death by water Monomers H-XXXX-OH H-YYY-OH H-ZZZZZ-OH Dehydration Synthesis make by taking water away H-XXXX- YYY- ZZZZZ-OH HOH HOH Polymer

  6. Endless variety of Polymers Order of Monomers Different Amounts of each monomer H-XXXX- YYY- ZZZZZ-OH H-YYY-XXXX- ZZZZZ-OH H-XXXX- ZZZZZ- YYY-OH H-ZZZZZ- YYY- ZZZZZ-OH

  7. 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 Figure 5.2A • Monomers form larger molecules by condensation reactions called dehydration reactions

  8. 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 Figure 5.2B • Polymers can disassemble by • Hydrolysis

  9. Polymers Monomers

  10. CARBOHYDRATES Sugars and Sugar Derivatives Polymers: Monomers: Polysaccharides Monosaccharides Simple Sugars Glucose Fructose Ribose Long chains of monomers storage starch: amylose amylopectin glycogen structure Fiber: cellulose Oligosaccharides Informational structures

  11. MONOSACCHARIDES = Carbohydrate Monomers O O = = • 1 Carbonyl - aldehyde or ketone R-C-H R1-C-R2 R-OH • All Other CARBONS • each have ONE alcohol group Expect them to be HYDROPHILIC Aldo sugar Keto sugar

  12. Triose sugars(C3H6O3) Pentose sugars(C5H10O5) Hexose sugars(C6H12O6) H H H H O O O O C C C C H C OH H C OH H C OH H C OH H C OH H C OH HO C H HO C H Aldoses H H C OH H C OH HO C H H C OH H C OH H C OH Glyceraldehyde H C OH H C OH H Ribose H H Glucose Galactose H H H H C OH H C OH H C OH C O C O C O HO C H H C OH H C OH Ketoses H C OH H C OH H Dihydroxyacetone H C OH H C OH H C OH H Ribulose H Figure 5.3 Fructose Monosaccharides Vary in length 3, 4, 5,6 or 7 carbons

  13. Also differ by SPATIAL GEOMETRY Carbon with 4 different functional groups Chiral or asymmetric carbon = “handed” carbon

  14. Plane of symmetry Left handed “L” form Right handed “D” form Stereoisomers not the same

  15. Not chiral Chiral Chiral Chiral Chiral Not chiral

  16. Triose sugars(C3H6O3) Pentose sugars(C5H10O5) Hexose sugars(C6H12O6) H H H H O O O O C C C C H C OH H C OH H C OH H C OH H C OH H C OH HO C H HO C H Aldoses H H C OH H C OH HO C H H C OH H C OH H C OH Glyceraldehyde H C OH H C OH H Ribose H H Glucose Galactose H H H H C OH H C OH H C OH C O C O C O HO C H H C OH H C OH Ketoses H C OH H C OH H Dihydroxyacetone H C OH H C OH H C OH H Ribulose H Figure 5.3 Fructose Spatial Geometry yields a variety of forms 8 Forms!

  17. 5 and 6 Carbon Sugars CIRCULARIZE in Water To FORM RINGS Haworth projection Fischer projection

  18. O H 1 C 6CH2OH 6CH2OH 2 CH2OH H C OH 5C H 5C O O 6 3 H O H H H H H 5 HO C H H HOH HOH 4 4C 1 C 1C 4C 4 1 OH H H H C OH O HO OH 3 2 OH OH 5 OH 2 C C 3 C 2C 3 OH H C H OH 6 H H OH OH H C OH H Figure 5.4 (a) Linear and ring forms. Chemical equilibrium between the linear and ring structures greatly favors the formation of rings. To form the glucose ring, carbon 1 bonds to the oxygen attached to carbon 5.

  19. Circularization causes another chiral carbon b-D-Glucose a-D-Glucose

  20. (a) Dehydration reaction in the synthesis of maltose. The bonding of two glucose units forms maltose. The glycosidic link joins the number 1 carbon of one glucose to the number 4 carbon of the second glucose. Joining the glucose monomers in a different way would result in a different disaccharide. CH2OH CH2OH CH2OH CH2OH O O O O H H H H H H H H 1–4glycosidiclinkage HOH HOH HOH HOH 4 1 H H H H OH OH O H OH HO HO OH O H H H H OH OH OH OH H2O Glucose Maltose Glucose CH2OH CH2OH CH2OH CH2OH O O O O 1–2glycosidiclinkage H H H H H H HOH HOH 2 1 H H HO H HO H Dehydration reaction in the synthesis of sucrose. Sucrose is a disaccharide formed from glucose and fructose.Notice that fructose,though a hexose like glucose, forms a five-sided ring. (b) OH H O O HO CH2OH HO CH2OH H OH H H OH H OH OH H2O Glucose Sucrose Fructose Figure 5.5 monomeric sugars coupled together by CONDENSATION REACTION Glycosidic bond Holds carbohydrates together

  21. Synthesis Requires Energy Input Breakdown Does not Require Energy Input

  22. Disaccharides, Oligosaccharides and Polysaccharides (two) (few) (many) Sucrose (glucose+ fructose) Cane Sugar Lactose (glucose+galactose) Milk Sugar Maltose (glucose+glucose) Beer DiSaccharides OligoSaccharides Dextran (short chain of glucose) Digested Starch Furans (short chain of fructose) Onions

  23. Polysaccharides Chloroplast Starch 1 m Amylose Amylopectin (a) Starch: a plant polysaccharide Figure 5.6 • Long chains of Millions of monomers • most common polymers made ONLY of GLUCOSE monomers • Storage reserves: • Starch amylose • amylopectin, glycogen • Structure: cellulose

  24. Mitochondria Giycogen granules 0.5 m Glycogen Figure 5.6 (b) Glycogen: an animal polysaccharide

  25. Glycogen (or Amylopectin) Polysaccharides of glucose chains in an a(1->4) linkage, with a(1->6) branches

  26. Structural Polysaccharides • Cellulose • Is also a polymer of glucose • But has different glycosidic linkages than starch • We can readily digest starches but cannot digest cellulose

  27. Figure 5.9 • Cellulose is indigestable to animals • Cows and termites have microbes in their stomachs to facilitate this process

  28. H O C CH2OH CH2OH OH H C H O O OH H H H H HO C H 4 4 1 OH H OH H HO OH H HO H C OH H OH OH H C OH H  glucose C  glucose H OH (a)  and  glucose ring structures CH2OH CH2OH CH2OH CH2OH O O O O 1 4 4 4 1 1 1 OH OH OH OH O O O O HO OH OH OH OH (b) Starch: 1– 4 linkage of  glucose monomers OH OH CH2OH CH2OH O O O O OH OH OH OH 4 O 1 HO OH O O CH2OH CH2OH OH OH (c) Cellulose: 1– 4 linkage of  glucose monomers Figure 5.7 A–C Starches: aglycosidic linkage OH “down” Cellulose: bglycosidic linkage OH “up”

  29. Cellulose ß(1->4) linkage Amylose a(1->4) linkage

  30. About 80 cellulose molecules associate to form a microfibril, the main architectural unit of the plant cell wall. Cellulose microfibrils in a plant cell wall Microfibril Cell walls  0.5 m Plant cells OH OH CH2OH CH2OH O O O O OH OH OH OH O O O O O OH CH2OH OH CH2OH Cellulose molecules CH2OH OH CH2OH OH O O O O OH OH OH OH O Parallel cellulose molecules are held together by hydrogen bonds between hydroxyl groups attached to carbon atoms 3 and 6. O O O O OH CH2OH OH CH2OH CH2OH CH2OH OH OH O O O O OH OH OH OH O O O A cellulose molecule is an unbranched  glucose polymer. O O OH CH2OH OH CH2OH Figure 5.8 • Glucose monomer

  31. Starch Polysaccharides although hydrophillic are generally Insoluble in water “polymer effect” • orders too much water around polymer • Polymer tends to hydrogen bond to itself • Polymer falls out of solution

  32. Polymer forms Secondary Structures Polymer hydrogen bonding to Itself

  33. If Denature Secondary Structure (Break Hydrogen Bonds of Polymer with Itself) Water will Hydrogen bond With Polymer RESULT IS BOUND WATERGEL

  34. Can FORCE polymer to stay Hydrated Sugar Derrivatives • Disrupt • Secondary • Structures • remain • Hydrated! Characteristics?

  35. Some Other Sugar Derivatives or Modified Sugars Missing one or more components: a. 5 carbon RIBOSE and DEOXYRIBOSE missing one alcohol b. Glycerol - 3 Carbon Sugar with alcohol in place of an aldehyde c. Sugar amines, Sugar acids have amine or carboxylic acid group or something else in place of an alcohol a. H H H H - - - b. H - C - C - C - H - - - OH OH OH c.

  36. Questions?

  37. LIPIDS hydrophobic character Steroids Triglycerides Phospholipids Membranes Hormones FATS OILS -long term storage depot MEMBRANES “Other” Fatty Acids and Glycerol

  38. F.A differ by: Fatty Acid: carboxylic acid with LONG hydrocarbon chain Chain length saturation

  39. C C C C C C C H C H O H C C C C C C C C C HO H H H H H H H H H H H H H H H H C OH Fatty acid (palmitic acid) H C OH H Glycerol (a) Dehydration reaction in the synthesis of a fat Ester linkage O H H H H H H H H H H H H H H H H H H O C C C C C C C C C C C C C C C C C H H H H H H H H H H H H H H H O H H H H H H H H H H H H H H H O C H C C C C C C C H C C C C C C C C C H H H H H H H H H H H H H H H O H H H H H H H H H H H H H H H H H C O C C C C C C C C C C C C C C C C H H H H H H H H H H H H H H H H • Fats • Are constructed from two types of smaller molecules, a single glycerol and usually three fatty acids H H H H H H H H O H H H H H H H H Figure 5.11 (b) Fat molecule (triacylglycerol)

  40. Triglycerides: 3 fatty acids linked to Glycerol by CONDENSATION SYNTHESIS ESTER Linkage

  41. Insoluble ! All hydrophobic Triglycerides Properties in Water

  42. Liquid Solid Unsaturated or Polyunsaturated Saturated FATS OILS WHY? Like Fig 3-28

  43. Stearic acid Figure 5.12 (a) Saturated fat and fatty acid • Saturated fatty acids • Have the maximum number of hydrogen atoms possible • Have no double bonds Stack nicely

  44. Oleic acid cis double bond causes bending Figure 5.12 (b) Unsaturated fat and fatty acid • Unsaturated fatty acids • Have one or more double bonds Do not Stack well

  45. Polar (charged) Head Very Hydrophobic Tail monolayer Free Fatty Acids Hydrolyzed Triglycerides micelle Fatty Acids amphipathic

  46. Phospholipids Glycerol linked to 2 fatty acids Fig 3-27 Phosphate Head Group Glycerol Fatty acid tails Fatty acid tails Nonpolar Polar

  47. + CH2 Choline N(CH3)3 CH2 O Phosphate Hydrophilic head – P O O O CH2 CH CH2 Glycerol O O C O C O Fatty acids Hydrophilic head Hydrophobic tails Hydrophobic tails (c) Phospholipid symbol (b) Space-filling model Figure 5.13 (a) Structural formula • Phospholipid structure • Consists of a hydrophilic “head” and hydrophobic “tails”

  48. Phospholipid Head Groups Hydrophillic! Polar groups

  49. Phospholipid Bilayer Form Boundaries

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