CHO chemistry 2024

Note on Carbohydrates

Page 3: Chemical Nature of Carbohydrates

  • Carbohydrates are polyhydroxyalcohols.

    • They contain a functional aldehyde or keto group.

    • Examples include glucose and fructose.

Page 4: Classification of Carbohydrates

  • Carbohydrates are classified based on hydrolysis products:

    • Simple Compounds: Contain one saccharide unit.

    • Oligosaccharides: Hydrolyze to form 2 to 10 monosaccharides.

    • Polysaccharides: Hydrolyze to yield more than 10 monosaccharides.

Page 5: Monosaccharides

  • Simplest form of sugars.

  • Classification methods:

    • By Number of Carbon Atoms: Trioses, Tetroses, Pentoses, Hexoses.

    • By Functional Groups:

      • Aldehyde group: Aldoses

      • Ketone group: Ketoses

Page 6: Important Derivatives of Monosaccharides

  1. Sugar Acids:

    • Aldonic Acids: Formed by oxidation of aldehyde group (e.g., gluconic acid).

    • Uronic Acids: Formed by oxidation of primary alcohol group (e.g., glucuronic acid).

  2. Sugar Alcohols: Formed by reduction of sugars (e.g., glycerol, ribitol, inositol).

  3. Deoxy Sugars: E.g., 2-Deoxyribose in DNA.

  4. Amino Sugars: Formed by replacing OH group with NH2 (e.g., glucosamine).

Page 9: Sugar Substitutes (Artificial Sweeteners)

  • Provide sweet taste with lower calories.

  • Types include:

    • Aspartame

    • Saccharin

    • Stevia

    • Sucralose

    • Sugar alcohols (e.g., erythritol, xylitol).

Page 10: Details on Artificial Sweeteners

  1. Aspartame: 180-200 times sweeter than sugar.

  2. Saccharin: 300-500 times sweeter, used in dietary products.

  3. Stevia: Derived from Stevia rebaudiana, used in soft drinks.

  4. Sucralose: 600 times sweeter, derived from sucrose.

  5. Sugar Alcohols: Slowly converted to glucose, less sweet than sucrose.

Page 11: Important Monosaccharides

  • Trioses: Glyceraldehyde and dihydroxyacetone.

  • Tetroses: Erythrose.

  • Pentoses: D-ribose (RNA) and 2-deoxyribose (DNA).

  • Hexoses:

    • Fructose (found in honey).

    • Galactose (component of lactose).

    • Glucose (main sugar in blood).

Page 12: Glucose

  • Most important carbohydrate.

  • Major metabolic fuel for mammals.

  • Precursor for other carbohydrates and involved in various biological processes.

Page 13: Disaccharides

  • Composed of 2 monosaccharide units.

    1. Maltose: Two D-glucopyranose units.

    2. Lactose: D-galactopyranose and D-glucopyranose.

    3. Sucrose: D-fructofuranose and D-glucopyranose.

Page 15: Polysaccharides

  • Composed of more than 10 monosaccharide units.

    • Homopolysaccharides: Composed of one type of monosaccharide.

    • Heteropolysaccharides: Composed of multiple types.

Page 17: Starch

  • Found in grains, fruits, and tubers.

  • Composed of amylose and amylopectin.

Page 18: Glycogen

  • Storage form of carbohydrates in animals.

  • Highly branched structure, mainly in muscles and liver.

Page 19: Cellulose

  • Major component of plant cell walls.

  • Non-hydrolyzable by amylase, contributes to dietary fiber.

Page 20: Heteropolysaccharides

  • Formed from multiple monosaccharide types.

  • Includes glycosaminoglycans (GAGs).

Page 21: Proteoglycans

  • Composed mainly of GAGs and proteins.

  • Functions include structural support and hydration in tissues.

Page 22: Functions of GAGs

  • Act as lubricants and shock absorbers.

  • Important in cell migration and wound healing.

Page 23: Specific GAGs

  • Heparin: Anticoagulant properties.

  • Keratan Sulfate: Important for corneal transparency.