Simple (?) Chemistry

Fundamental Chemical Principles

• Living systems are integral parts of the universe and must obey the fundamental laws of chemistry and physics.
  • Elements essential to life
    • Atomic number
    • The structure of atoms
    • Mass Number
      • Isotopes
    • The electron cloud
    • How electrons determine chemistry
      

The glue of life: Chemical Bonds

An atoms properties depend on the number of electrons in it's outer shell.

• Bonds between ions
  • Electron donor/acceptor (e.g. Na+; Cl-)
    • Electrostatic interaction
    • Ionic Bond
    • Bonding capacity (Valance)
      • CaCl₂
  • Molecular formation (Stability; single electrical neutral entity)
    • ionization

Acids and Bases

• Living systems are extremely sensitive to the fluid that bathe them
• Acid: substance that increases the concentration of hydrogen ions
• Base: substance that reduces the concentration of hydrogen ions
  • pH
  • Buffers: carbonic acid

Covalent bonds are strong bonds: they can be broken with relatively large amounts of energy

• How strong bonds differ from ionic bonds by sharing electrons rather than transferring electrons from one atom to another
• Covalently bonded molecules are stable (50-110 kcal/mol)
  • Covalent Bonds
    • Nonpolar bonds
    • Polar bonds
      • Electronegativity

Weak chemical bonds play a crucial role in stabilizing macromolecules

• Strong versus weak bonds
  • Homeostasis
• Hydrogen Bonds (4-5 kcal/mol)
  • Strength in numbers
• Van der Waals Interactions (1-2 kcal/mol)
  • Interaction between molecules

Why life needs inorganic molecules

• Organic compounds-complex molecules that contain C
• Inorganic compounds- all noncarboneous molecules
  • Basic to the chemistry of life

Remarkable chemistry of water

• Water as a solvent
  • Arises as a function of it's polarity
    • Polar and ionic compounds are soluble in water
      • Hydration (ionic)
      • Hydrophilic (nonionic)
      • Hydrophobic (nonpolar)

The stickiness of water

• Bound water
  • immobilized water in hydration spheres
• Surface tension
  • Inter-molecular bonds
• Wettability
  • Capillarity

Water as a temperature regulator

• Heat capacity: amount of energy required to change the temperature by 1 ⁰C
• Heat of vaporization: amount of heat energy required for evaporation

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