Comprehensive Notes on Carbohydrate Classification and Chemistry

Classification and Characteristics of Monosaccharides

  • Definition:

    • Monosaccharides are the simplest carbohydrates that cannot be hydrolyzed further to give other simple sugars.

  • Classification by Carbon Atom Count:

    • Triose (3-carbon carbohydrates):
    • Example: Dihydroxyacetone (Dihydroxy acetone)
    • Tetrose (4-carbon carbohydrates):
    • Examples: Erythrose, Xylotose
    • Pentose (5-carbon carbohydrates)
    • Hexose (6-carbon carbohydrates):
    • Examples: Glucose, Fructose
    • Functional Classifications: Glucose acts as an aldehyde (aldose), whereas Fructose acts as a ketose.
    • Heptose (7-carbon carbohydrates):
    • Example: Sedoheptulose (Seudoheptulose)

Oligosaccharides and Disaccharides

  • Definition of Oligosaccharides:

    • Oligosaccharides are carbohydrates that produce 2 to 10 molecules of monosaccharides upon hydrolysis.

  • Disaccharides:

    • Disaccharides are a specific class of oligosaccharides that yield exactly two monosaccharide molecules upon hydrolysis.
    • Common Disaccharide Combinations:
    • Maltose: Formed from Glucose + Glucose
    • Lactose: Formed from Glucose + Galactose
    • Sucrose: Formed from Glucose + Fructose

  • Chemical Reactions and Formulas:

    • Reaction of Monosaccharides to form Disaccharides:

Glucose+Fructose→Sucrose+H2O\text{Glucose} + \text{Fructose} \rightarrow \text{Sucrose} + \text{H}_2\text{O}

  • Chemical Equation using Molecular Formulas:

C6H12O6+C6H12O6→C12H22O11+H2O\text{C}_6\text{H}_{12}\text{O}_6 + \text{C}_6\text{H}_{12}\text{O}_6 \rightarrow \text{C}_{12}\text{H}_{22}\text{O}_{11} + \text{H}_2\text{O}

Polysaccharides

  • Definition:

    • Polysaccharides are carbohydrates which give a large number of monosaccharides (composed of either the same or different monosaccharides) upon hydrolysis.

  • Examples:

    • Starch
    • Cellulose
    • Glycogen