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2014-01-24 14:39:35

Carbohydrates: part 1
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  1. What two groups are considered as simple carbohydrates?

    • -disaccharides
    • *2 monosaccharides joined by covalent bond
  2. what are the 2 complex carbohydrates?

  3. what are oligosaccharides?
    short chains of monosaccharides (3-10)
  4. what are polysaccharides?
    long chains of monosaccharides (>10)
  5. reactions between saccharides) HYdration reactions- Hydrolysis
    an H2O molecule breaks a bond
  6. reactions between saccharides) dehydration reactions:
    reverse of hydrolysis, it removes H2O to bond 2 molecules together
  7. what 2 consequences occur because we are mostly made up of water?
    -hydrolysis happens easily

    -dehydration reactions require energy to perform
  8. what are the 3 major dietary monosaccharides?


  9. what form of structure does the monosaccharide  take in water?
    a ring structure
  10. how are monosaccharides often referred to depending on their functional group? (2)

  11. can monosaccharides be broken down through mild hydrolytic reactions?
  12. what are stereoisomers-enantiomers?
    -same structure with similar chemical properties but in reverse form
  13. Do stereoisomers-enantiomers react the same? If yes/no why?
    • no, they react completely different in the body  due to stereo-specific receptors in the body
    • *D-glucose vs. L-glucose
    • *bodies can digest D-glucose but not L-glucose
  14. Glucose+Glucose=
    Maltose α(1-4) bond
  15. Glucose+Galactose=
    Lactose β(1-4) bond
  16. Glucose+Fructose=
    sucrose α1 β2 bond
  17. Oligosaccharides are made from a combination of which 3 monos?
    • -glucose
    • -fructose
    • -galactose
  18. which two foods are oligosaccharides found in?
    -beans and peas
  19. can our enzymes break down oligosaccharides bonds?
    no they cannot
  20. what type of enzymes can break down oligosaccharides? and what does this lead to?
    microflora's enzymes, this leads to gas from bean and pea consumption
  21. what is the major storage form of carbohydrates?
  22. polysaccharides) Homopolysaccharides:
    made of one type of monosaccharide
  23. polysaccharides) Heteropolysaccharides:
    made of two or more types of monosaccharide
  24. polysaccharides) which 3 polysaccharides are common in homopolysaccahrides?
    • -starch
    • -glycogen
    • -cellulose
  25. are homopolysaccharides abundant in foods?
  26. Are heteropolysaccharides abundant in foods?
    no they are not
  27. polysaccharides) what is the major storage form  in plants?
  28. polysaccharides) Starch- How are amylose formed?
    glucose connected solely through alpha(1-4) glycosidic bonds
  29. polysaccharides) Starch- How are amylopectin?
    • glucose connected through alpha(1-4) and alpha(1-6) glycosidic bonds
    • *it is a branched structure
  30. polysaccharides) what is the major storage form for carbs in humans?
  31. polysaccharides) Glycogen has similar bonds as...
  32. polysaccharides) Cellulose is a major component of..
    plant cell walls
  33. polysaccharides) what is the main difference in structure that differ between starch and cellulose?
    CEllulose has beta(1-4) instead of alpha(1-4) connecting the monosaccharides
  34. polysaccharides) why is it significant that cellulose has beta bonds connecting monosaccharides instead of alpha?
    • our alpha-amylase can only digest alpha bonds thus makes cellulose indigestible by humans
    • *considered as indigestible fiber
  35. digestion of polysaccharides) where does it begin?
    in the mouth
  36. digestion of polysaccharides) what are 2 things that salivary alpha-amylase do?
    -breaks alpha(1-4) bonds to release glucose from starch and glycogen

    -follows bolus into the stomach, then it is deactivated by pH level change
  37. digestion of polysaccharides) which 2 types of bonds are resistant to salivary alpha-amylase?
    -beta(1-4) bonds of cellulose

    -alpha(1-6) bonds of amylopectin and glycogen
  38. digestion of polysaccharides) what does pancreas do when bolus arrives at intestines? (2)
    -release bicarbonate to increase pH

    -releases pancreatic alpha-amylase to continue liberating glucose
  39. digestion of polysaccharides) what are the limit dextrins?
    • 1 alpha(1-6) + a few alpha(1-4)
    • *these were the ones that were left off because alpha-amylase could not break these down
  40. digestion of polysaccharides) what happens to the "few" alpha(1-4) from limit dextrins ?
    they are removed with a debranching enzyme
  41. digestion of polysaccharides) after the few alpha(1-4) from limit dextrins are removed, whats left and what is it called?
    Isomaltose, which is a 3-glucose triose with a 1 alpha(1-6) bond
  42. digestion of polysaccharides) Finally what cleaves the alpha(1-6) bond to complete the breakdown to monosaccharides? and where can it be found?
    alpha-dextrinase or isomaltase, which can be found at the brush border
  43. carbohydrate inhibitor) what can beans with amylase inhibitors do?
    -sugar and starch are absorbed as monosaccharides because it would inhibit their breakdown from poly to mono.
  44. carbohydrate inhibitor) what can the concept of beans having amylase inhibitors theoretically present?
    it could inhibit the digestion of carbohydrates and lead to weight loss
  45. carbohydrate inhibitor) was the research on this sufficient?
    no, it was spotty and insufficient
  46. digestion of poly/di/mono) where does chemical digestion begin? and with what 2 things does it start with?
    mouth, amylose and amylopectin
  47. digestion of poly/di/mono) What happens to the activity of salivary amylase in the stomach?
    it is inactivated bc of pH levels
  48. digestion of poly/di/mono) is there carbohydrate digestion in the stomach?
  49. digestion of poly/di/mono) what occurs in the small intestines?c
    carbohydrate breakdown resumes bc the pancreas release pancreatic alpha-amylase
  50. digestion of poly/di/mono) what occurs at the brush border?
    final breakdown into monosaccharides occurs
  51. digestion of poly/di/mono)what do maltase do?
    breaks alpha(1-4) glycosidic bonds
  52. digestion of poly/di/mono) what do lactase do?
    breaks beta(1-4) glycosidic bonds
  53. digestion of poly/di/mono) what does sucrase do?
    breaks the alpha1beta2 glycosidic bond