biochem 010 carbohydrates part 1(monosaccharide disaccharide polysaccharide) #17

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biochem 010 carbohydrates part 1(monosaccharide disaccharide polysaccharide) #17
2014-11-17 18:02:33
biochem 010 carbohydrates part monosaccharide disaccharide polysaccharide 17
biochem 010 carbohydrates part 1(monosaccharide, disaccharide, polysaccharide) #17
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  1. what are the names given to carbs based on how many C's they have?
    triose, tetrose, pentose, hexose, heptose
  2. carbohydrates exist in many ______ forms
  3. sugars can be either ____ or _____ based on where the carbonyl group is located
    aldose, ketose
  4. pyranose rings interconvert between the ____ and _____ form
    chair, boat
  5. what are three common molecules that monosaccharides are joined to in order to increase their biochemical versatility?
    alcohols, amines and phosphates
  6. oligosaccharides are made by certain enzymes called ________
  7. what two monosaccharides are joined to form lactose?
    glucose and galactose
  8. what type of glycosidic linkage is found in lactose?
    β-1,4-glycosidic linkage
  9. what is a homopolymer?
    a polymer made of the same, repeating monomers
  10. Most of the glucose units in glycogen are linked by _________ ____. The branches are formed by ________ ______, present about once in ___ units.
    α-1,4-glycosidic bonds, α-1,6-glycosidic bonds, 10
  11. what are the two forms of starch? how are they different?
    Amylose is a linear polymer of glucose units linked by α-1, 4-glycosidic bonds.

    Amylopectin is a branched polymer,with an α-1, 6-glycosidic bond for every 30 α-1,4-glycosidic bonds.
  12. what is a pyranose?
    • In the case of glucose, the resulting
    • intramolecular hemiacetal,
    • a six-carbon ring, is called a pyranose because of its resemblance to pyran.
  13. what is a furanose?
    • In the case of the ketose fructose, the intramolecular hemiketal,
    • a five-carbon ring, is called a furanose because of its resemblance to furan.
  14. what is an anomer?
    Cyclization of a sugar molecule causes the formation of 2 new diasteriomers. They differ in the position of the attachment of a certain group (discussed later) to the new stereocenter. The new stereocenter is referred to as the anomeric carbon.

  15. how does one locate the anomeric carbon in a ring?
    Look at the carbons on either side of the oxygen. One will be attached to a CH2OH group. Do not focus on this one. The carbon on the other side is the anomeric carbon!

  16. what is the difference between an α and a β anomeric carbon?
    Depending on the direction of the OH group, the anomeric carbon is either α or β

    α: equatorial DOWN or axial DOWN

    β: equatorial UP or axial UP

  17. what is an O-glycosidic bond?
    • A bond formed between the anomeric
    • carbon atom and a hydroxyl group of another molecule is called an O-glycosidic
    • bond, and the product is called a glycoside.
  18. what is an N-glycosidic bond?
    • A bond formed between the anomeric
    • carbon atom and an amine is called an N glycosidic bond.
  19. carbohydrates form ____ linkages with phosphates