Structure

• elements present: C,H,O in the ratio 1:2:1
• monomer: monosaccharide (single sugar)
  • glucose, fructose, galactose
  • bonded together by glycosidic linkage
• polymers are polysaccharides
  • plants: starch and cellulose
  • animals: glycogen and chitin
• directionality and nature of bonding allow for a certain orientation of each monomer
  • determines secondary structure of carb
• Functions:

  • main source of energy

  • energy storage

    • starch and glycogen

  • building material (structural support)

    • cellulose, fiber, and chitin

    

Isomers in Carbohydrates

• Structural: have different sequence of the atoms compared to each other

  • alpha-glucose and beta-glucose
    • alpha glucose creates starch and beta glucose creates cellulose

• Optical: are mirror images of each other

  • D-glucose and D-mannose

  

  

Branching in Structure

• The amount of branching of a polysaccharide is dependent on the type of monosaccharides present and the bonds created between them.

• For example, 1,4 glycosidic bonds create unbranched chains, while 1,6 glycosidic bonds create very branched molecules

  • Starch has less 1,6 glycosidic bonds than glycogen, so it is less branched