Lecture 2: Body Chemistry Overview

Introduction

• Continuation of Chapter 2 on body chemistry, focusing on chemistry's role in the human body.
• Reviewed concepts: matter and energy, atom bonding, chemical reactions, molecules (inorganic vs organic).

Water and Its Properties

• Water as a polar molecule due to electronegativity difference between oxygen and hydrogen.
• Properties of Water:
  • Partial charges on oxygen (negative) and hydrogen (positive).
  • Surface tension, solubility (dissolves salts like chloride and sodium).
• Aqueous Solutions:
  • Electrolytes: Ionic solutions that carry electrical charges, e.g., sodium, potassium, calcium.
  • Importance in body fluids and health.

Acids, Bases, and pH

• pH Scale: Measures hydrogen ion concentration.
• Acids: Donate hydrogen ions (protons), e.g., hydrochloric acid.
• Bases: Remove hydrogen ions or add hydroxide ions.
• Buffers:
  • Resist rapid pH changes.
  • Important for maintaining blood pH.
  • Example: Antacids as weak bases.

Organic Molecules

• Characterized by hydrocarbons (C bonded to H).
• Four Classes:
  1. Carbohydrates
  2. Lipids
  3. Proteins
  4. Nucleic Acids

Carbohydrates

• Composed of carbon, hydrogen, and oxygen.
• Types:
  • Monosaccharides (e.g., glucose)
  • Disaccharides (e.g., sucrose)
  • Polysaccharides (e.g., glycogen for energy storage)

Lipids

• Hydrophobic, insoluble in water.
• Types:
  • Fatty acids (saturated vs unsaturated)
  • Triglycerides (energy storage form)
  • Phospholipids (form cell membranes)

Chemical Concepts

• Redox Reactions: Electron exchange crucial for metabolism (e.g., glucose oxidation).
• Hydrophobic vs Hydrophilic:
  • Hydrophobic (water-fearing) vs hydrophilic (water-attracted) molecules.

Additional Topics

• Soap Chemistry: Amphipathic nature allows interaction with both oils and water, aiding in cleaning.

Conclusion

• Overview of inorganic and the start of organic chemistry.
• Next session will cover proteins and conclude the chapter.