Carbohydrates

• structure of glycogen

  • polymer of α-glucose joined by alpha 1,4 and 1,6 glycosidic bonds
  • Branched so has many ends for hydrolysis
  • coiled makes the molecule compact
  • Insoluble so water potential is not affected
  • Large so can't cross cell membrane
• Structure of starch

  • polymer of α-glucose joined by alpha 1,4 and 1,6 glycosidic bonds
  • Branched so many ends for hydrolysis
  • Large so can't cross the cell membrane
  • Coiled so makes molecule compact
  • Insoluble so water potential is not affected
• Structure of cellulose

  • polymer of beta-glucose joined by beta 1,4-glycosidic bonds
  • long, straight, unbranched chains
  • weak hydrogen bonds between unbranched and straight chains of b-glucose
  • polysaccharide chains are grouped into microfibrils
• Structure of amylose

  • 1-4 glycosidic bonds
  • hydrogen bonds makes it compact
  • unbranched chains
  • coiled so very compact to store a lot of energy
• Structure of amylopectin

  • 1-4 and 1-6 glycosidic bonds
  • side branches means many terminal ends for hydrolysis into glucose
• Define monosaccharide

  a monomer from which larger carbohydrates can be made
• Examples of monosaccharides


  • glucose
  • fructose
  • galactose
• Examples: disaccharides


  • Maltose
  • Sucrose
  • Lactose
• Examples of polysaccharides


  • Amylose (plants)
  • Amylopectin (plants)
  • Glycogen (animals)