carbohydrates

• Carbohydrate


  A polyhydroxyaldehyde or polyhydroxyketone, or a substance that gives these compounds on hydrolysis
• Monosaccharide


  A carbohydrate that cannot be hydrolyzed to a simpler carbohydrate
• Monosaccharides


  • Have the general formula CnH2nOn, where n varies from 3 to 8
  • Aldose: A monosaccharide containing an aldehyde group
  • Ketose: A monosaccharide containing a ketone group
• Trioses


  • Glyceraldehyde
• Fischer projection


  A two-dimensional representation for showing the configuration of tetrahedral stereocenters
• 1. monosaccharide


  The -OH on its penultimate carbon is on the right in a Fischer projection

  
• 1. monosaccharide


  The -OH on its penultimate carbon is on the left in a Fischer projection

  
• Common D-tetroses and D-pentoses

  • List not provided
• Three most common D-hexoses

  • List not provided
• Amino sugars


  Contain an -NH2 group in place of an -OH group
• Cyclic structure


  Aldehydes and ketones react with alcohols to form hemiacetals
• Haworth projection


  A planar representation of the cyclic hemiacetal structure
• Anomeric carbon


  The new carbon stereocenter created in forming the cyclic structure

  
• Anomers


  Stereoisomers that differ in configuration only at the anomeric carbon
• Pyranose


  A six-membered hemiacetal ring
• Furanose


  A five-membered hemiacetal ring
• Deoxy


  Without oxygen
• Chair conformation


  A strain-free representation of the six-membered pyranose ring
• Mutarotation


  The change in specific rotation that accompanies the equilibration of a- and b-anomers in aqueous solution
• Glycoside


  A cyclic acetal derived from a monosaccharide
• Glycosidic bond


  The bond from the anomeric carbon to the -OR group
• Alditol


  The reduction product of a monosaccharide where the carbonyl group is reduced to a hydroxyl group
• Alditols


  • Sorbitol
  • Mannitol
  • Xylitol
• Aldonic acid


  The oxidation product of an aldose where the aldehyde group is oxidized to a carboxylate anion
• Reducing sugar


  A carbohydrate that reacts with an oxidizing agent to form an aldonic acid
• Sucrose


  Table sugar, obtained from the juice of sugar cane and sugar beet
• Lactose


  The principle sugar present in milk
• Maltose


  From malt, the juice of sprouted barley and other cereal grains
• Polysaccharide


  A carbohydrate consisting of large numbers of monosaccharide units joined by glycosidic bonds
• Starch


  A polymer of D-glucose
• Amylose


  • Unbranched chains of up to 4000 D-glucose units joined by a-1,4-glycosidic bonds
• Amylopectin


  • Chains up to 10,000 D-glucose units joined by a-1,4-glycosidic bonds, with branches consisting of D-glucose units joined by a-1,6-glycosidic bonds
• Glycogen


  The energy-reserve carbohydrate for animals, a branched polysaccharide of approximately 10^6 glucose units joined by a-1,4- and a-1,6-glycosidic bonds
• Cellulose


  • A linear polysaccharide of D-glucose units joined by b-1,4-glycosidic bonds, with an average molecular weight of 400,000 g/mol and approximately 2200 glucose units per molecule
  • Cellulose molecules align themselves side by side into well-organized water-insoluble fibers, giving cellulose high mechanical strength
• Humans and other animals cannot digest cellulose because their digestive systems do not contain b-glycosidases, enzymes that catalyze the hydrolysis of b-glycosidic bonds</b>
• Acidic polysaccharides


  A group of polysaccharides that contain carboxyl groups and/or sulfuric ester groups, and play important roles in the structure and function of connective tissues
• Heparin


  An acidic polysaccharide synthesized and stored in mast cells, with anticoagulant activity due to its binding to antithrombin III