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.