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Organic Macromolecules

Organic Macromolecules. Macromolecules. Smaller organic molecules join together to form larger molecules macromolecules 4 major classes of macromolecules: carbohydrates lipids proteins nucleic acids. Polymers. Long molecules covalently bonded by linking chains of repeating smaller units

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Organic Macromolecules

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  1. Organic Macromolecules

  2. Macromolecules • Smaller organic molecules join together to form larger molecules • macromolecules • 4 major classes of macromolecules: • carbohydrates • lipids • proteins • nucleic acids

  3. Polymers • Long molecules covalently bonded by linking chains of repeating smaller units • polymers • monomers = repeated small units • each cell has millions of diff macromolecules Think: 26 letters of alphabet for all possible combinations

  4. How to break down a polymer • Hydrolysis • use H2O to break apart monomers • reverse of condensation reaction • H2O is split into H and OH • H & OH group attach where the covalent bond used to be • ex: digestion is hydrolysis

  5. http://nhscience.lonestar.edu/biol/dehydrat/dehydrat.html

  6. Carbohydrates • So what’s all this talk about carbs?? • Atkin’s Diet & South Beach Diet

  7. 1. contain C, H, O 2. 1:2:1 ratio 3. provide energy or storage 4. many end in “ose” 5. three main groups – monosaccharides, disaccharides, polysaccharides

  8. Carbohydrates • Carbohydrates are composed of C, H, O carbo - hydr - ate CH2O (CH2O)x C6H12O6 • Function: • energy u energy storage • raw materials u structural materials • Monomer: single sugar molecules (monosaccharides) • ex: sugars & starches

  9. Sugars • Most names for sugars end in -ose • Classified by number of carbons • 6C = hexose (glucose) • 5C = pentose (fructose, ribose) • 3C = triose (glyceraldehyde): imp intermediate in metabolic process of cell respiration (burning glucose for energy)

  10. What functional groups? carbonyl aldehyde ketone hydroxyl

  11. Sugar structure why? • 5C & 6C sugars form rings in aqueous solutions • in cells! Carbons are numbered chain forms: hydroxyl on last C reacts w/aldehyde (C=O) on 1st C

  12. Numbered carbons C 6' C O 5' C C 4' 1' C C 3' 2'

  13. Simple & complex sugars • Monosaccharides • simple 1 monomer sugars • glucose • Disaccharides • 2 monomers • sucrose • Polysaccharides • large polymers • starch

  14. a. Monosaccharides: • simplest form of carbohydrates • building blocks for larger carbohydrates (also called monomers) • usually contain molecular formula C6H12O6 • isomers: glucose, fructose, galactose • glucose (blood sugar), fructose & galactose (fruit sugars) • can occur as straight (open) chains or as rings • numbering of carbon atoms in ring depends on the straight chain (always # the carbon atoms so that the carbon attached to the functional group is the smallest number possible)

  15. Glucose in the open chain and ring form

  16. Building sugars • Dehydration synthesis: putting together monomers by taking out water (req’s energy & enzymes) monosaccharides disaccharide | glucose | fructose | sucrose glycosidic linkage: can be alpha or beta which changes the orientation of the 2 monosaccharides to each other structural isomers “Let’s go to the video tape!” (play movie here)

  17. Isomers of Glucose anomers (2 different ring forms)

  18. Lactose: β-1,4 linkage (the 1,4 tells you where the 2 molecules are bonded to each other)

  19. b. Disaccharides: • C12H22O11 (molecular formula) • 2 monosaccharides joined • twice the energy • sucrose (table sugar) = 1 glucose + 1 fructose • maltose (found in sugar cane) = 1 glucose + 1 glucose • lactose (milk sugar) = 1 glucose + 1 galactose • maltose has alpha linkage (bottom to bottom) • sucrose has alpha linkage (bottom to bottom) • lactose has beta linkage (top to bottom) • 1,4 or 1,2 numbering tells you what carbon numbers the linkage is being formed at

  20. Polysaccharides (polymers of hundreds to thousands of monosaccharides) • Polymers of sugars • costs little energy to build • easily reversible = release energy • Function: • energy storage • starch (plants) • glycogen (animals) • building materials = structure • cellulose (plants) • chitin (arthropods & fungi)

  21. c. Polysaccharides: • (C6H10O5)n [molecular formula] • N= 5-5,000 monosaccharides • Form chains of polymers (repeating monomer units) • 2 main functions: food storage and structure • Food storageStructure cellulosechitin plant starchesanimal starches amyloseamylopectinglycogen

  22. Branched v linear polysaccharides(made of repeating glucose monomers) Q: can you see the difference between starch & glycogen? Which is easier to digest?

  23. Glycogen α -1,4 linkage on the straight chain α -1,6 linkage at the branch points (every 10 glucose molecules)

  24. Polysaccharide diversity • Molecular structure determines function • isomers of glucose • How does structure influence function…

  25. Amylose v Amylopectin Amylose: straight chain with α -1,4 linkage Amylopectin: - α -1,4 linkage on the straight chain with α -1,6 linkage at the branch points (every 30 glucose molecules)

  26. Amylose straight chain that forms a helical structure in water uses α glucose α-1,4 linkage used for storage (starch) in plants soluble in water Cellulose straight chain uses β glucose β-1,4 linkage (every other glucose subunit is inverted) cannot be digested by animals (lack the enzyme cellulase) used for support makes up plant cell walls insoluble in water Comparison of Cellulose vs. Amylose

  27. Cellulose in Plant Cell Walls Parallel cellulose molecules are held together by hydrogen bonds.

  28. Cellulose • Most abundant organic compound on Earth • Cross-linking between polysaccharide chains: rigid & hard to digest Think herbivores: spend a lot of time digesting food w/help of microbes

  29. Digesting starch vs. cellulose (starch: all the glycosidic linkages are on same side: molecule lies flat)

  30. Cow can digest cellulose well; no need to eat supplemental sugars Gorilla can’t digest cellulose well; must supplement with sugar source, like fruit

  31. forms the exoskeletons of arthropods used to make a strong and flexible surgical thread that decomposes after the wound or incision heals makes up the cell walls of some fungi Chitin The structure of the chitin monomer

  32. Glycemic index • Which food will get into your blood more quickly? • apple • rice cakes • corn flakes • bagel • peanut M&M

  33. Glycemic index • Ranking of carbohydrates based on their immediate effect on blood glucose (blood sugar) levels • Carbohydrate foods that breakdown quickly during digestion have the highest glycemic indices. Their blood sugar response is fast & high.

  34. Glycemic index • Which food will get into your blood more quickly? • apple 36 • rice cakes 82 • corn flakes 84 • bagel 72 • peanut M&M 33

  35. Let’s build some Carbohydrates!

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