Lecture on Carbohydrates and Lipids

Introduction

• Topic: Carbohydrates
• Relevance: Part of B1.1, core/standard level material on carbohydrates and lipids
• Key Concept: Carbon-based molecules
  • Carbon is versatile in forming four stable covalent bonds.

Carbon Bonds and Structures

• Covalent Bonds: Shared electrons between two atoms
• Structure Types:
  • Chains (e.g., saturated fatty acids)
  • Rings (e.g., monosaccharides)

Macromolecules

• Formation: Linking smaller units (monomers) to form polymers
• Condensation Reactions:
  • Involves removal of water to form bonds
  • Forms glycosidic bonds between sugars
• Hydrolysis: Adding water to break apart molecules (important in digestion)

Types of Saccharides

• Monosaccharides: Simple sugars (e.g., glucose, ribose)
• Disaccharides: Two monosaccharides bonded (e.g., maltose)
• Polysaccharides: Many monosaccharides (e.g., starch, glycogen, cellulose)
  • Amaloptin: Form of starch with alpha-1,4 and 1,6 linkages
  • Starch: Energy storage in plants
  • Glycogen: Energy storage in animals

Monosaccharides

• Glucose: C₆H₁₂O₆, polar and soluble, important in energy release (cell respiration)
• Types of Sugars:
  • Trioses (3-carbon)
  • Pentoses (5-carbon, e.g., ribose)
  • Hexoses (6-carbon, e.g., glucose)

Polysaccharides Function

• Cellulose: Structural support in plant cell walls
• Starch (Amalo and Amaloptin): Energy storage in plants
  • Amalo: Linear with 1,4 linkages
  • Amaloptin: Branched with additional 1,6 linkages
• Glycogen: Highly branched, energy storage in animals

Glycoproteins

• Definition: Proteins with carbohydrate chains
• Function: Cellular recognition (e.g., blood types)
  • Blood Types: A, B, AB, O linked to specific glycoproteins on cells
  • Immune Response: Recognition of antigens by immune system

Key Takeaways

• Carbon's versatility leads to complex biological molecules.
• Condensation and hydrolysis are key reactions in forming and breaking macromolecules.
• Structural and functional diversity of carbohydrates is crucial in biological processes.