Disaccharides: Transport Forms

• Sugars are often transported in other organisms as Disaccharides
  • Sucrose
    • Form of sugar transported in plants from photosynthetic cells to other parts
    • Composed of the monosaccarides glucose and fructose
  • Trehalose
    • Form of sugar found in insect bloodstreams
    • Two glucose units linked together
  • Lactose
    • Occurs only in milk
    • Glucose combined with galactose

• In the synthesis of a disaccharide molecule from two monosaccharides, condensation occurs (OH and H is removed so carbons can bond.) Thus, only the free monomers of carbohydrates actually have a CH₂O ratio.
• When a disaccharide is split into two monosaccharides, hydrolysis occurs (H₂O is added.) Hydrolysis is an energy releasing reaction. The energy needed for synthesis is provided by hydrolysis