Carbohydrates

• Glucose structure

  
• Carbohydrates

  • carbon, hydrogen, oxygen
  • simple carbs= sugars
  • Polymers
  • Monomers of carbs= monosaccharides
• Monosaccharides

  • glucose, fructose, galactose
  • Energy releases to make ATP (instant energy)
• Glucose

  • Alpha and beta (different structures)
  • Isomers
• Alpha-glucose

  • Polymerises to form energy storage compounds: starch, glycogen
• Beta-glucose

  • polymerises to form cellulose
• Disaccharides

  Form during a condensation reaction

  examples: maltose, sucrose, lactose
• Maltose

  composed of 2 alpha-glucose
• Sucrose

  Glucose + Fructose (pentose sugar)
• Lactose

  Glucose + Galactose
• Polysaccharides

  • Complex carbs
  • large molecules made from monosaccharides
  • Energy storage/structure
  • Insoluble
• Starch (plants)


  • polymer of glucose
  • doesn't make water potential of cytoplasm too low
  • broken down into glucose for energy
  • mixture of amylose and amylopectin
  • 1-6 links
• Amylose

  • long unbranched chain of alpha-glucose
  • coiled, helical structure
  • Compact molecule
  • good for storage
  • Glycosidic bonds (1-4)

  
• Amylopectin

  • long, branched chains of alpha-glucose
  • Branches allow hydrolysing enzymes to access glycosidic bonds quicker
  • Glucose is released quickly
  • 1-6 glycosidic bonds allows branching

  
• Glycogen (animals)

  • Stores excess glucose
  • polysaccharide of alpha-glucose
  • more branches than amylopectin (glucose needs to be released quicker)
  • Helix/coiled
  • Stored in liver/muscle cells
  • short term energy store
  • 1-6 links

  
• Cellulose (plants)

  • Most common polysaccharide
  • beta-glucose polymer
  • Forms fibres
  • strong (microfibris) structural support
  • long, straight, unbranched chains
  • when chains lie parallel, hydrogen bonds link them