Chemistry of Life: Inorganic/Organic/Macromolecules

Chemistry of Life: Inorganic Compounds and Their Importance

• Basic Reactions:

  • A chemical reaction follows the formula: Reactants (start) ⟶ Products (finish).
  • Many reactions are reversible.

• Essential Inorganic Compounds:

  • Required by organic creatures and include:
    • $H_2O$ (Water)
    • $O_2$ (Oxygen)
    • $CO_2$ (Carbon Dioxide)
    • Minerals such as Zinc (Zn), Magnesium (Mg), Calcium (Ca).

Acids, Bases, and pH

• Water's Ionization:

  • Water can disassociate into hydrogen ions (H⁺) and hydroxide ions (OH⁻).
  • Acids: Compounds that release H⁺ in solutions (pH < 7).
  • Bases: Compounds that release OH⁻ in solutions (pH > 7).
  • Neutral Compounds: Have equal concentrations of H⁺ and OH⁻, yielding a pH of 7.

• Buffers in Biology:

  • Maintain narrow pH ranges crucial for protein function.
  • Avoid protein unfolding, which leads to denaturation and loss of function.

Chemical Bonds and Water Properties

• Chemical Bonds:

  • Valence Electrons: Electrons available for bonding found in an atom's outer shell.
  • Major bond types:
    1. Ionic Bonds
    2. Covalent Bonds
    3. Hydrogen Bonds: Weaker bonds between H of one water molecule and O of another; not formed between two hydrogen atoms.

• Water Structure:

  • Polar molecule with unequal electron sharing, resulting in partial charges (negative on O, positive on H).

• Cohesion & Adhesion:

  • Cohesion: Attraction between similar molecules.
  • Adhesion: Attraction between different molecules.

• Heat Properties:

  • Heat of Vaporization: High energy required to vaporize water.
  • Specific Heat: Water’s resistance to temperature changes allows for cellular regulation.
  • Density: Ice is less dense than liquid water, causing it to float, essential for aquatic life in colder climates.

Organic Compounds and Macromolecules

• Overview of Organic Compounds:
  • Composed of carbon (C), generally requiring at least 5 carbon atoms.
  • Often include hydrogen (H) and oxygen (O), and may also contain nitrogen (N), phosphorus (P), and sulfur (S).
  • Carbon’s valence of 4 allows it to form diverse compounds, including chains, branches, different bond types, and rings.

Polymer Science

• Polymers: Large molecules made of repeating smaller units (monomers).
  • Examples include DNA, RNA, and proteins.
• Monomers: Singular units like nucleotides and amino acids.

Metabolism: Anabolic and Catabolic Processes

• Anabolism:

  • Build-up processes requiring energy; larger molecules are formed (e.g., $A + B ⟶ AB$).
  • Examples include photosynthesis and protein synthesis.
  • Involves dehydration synthesis, where water is released during bond formation.

• Catabolism:

  • Breakdown processes that release energy (e.g., $AB ⟶ A + B$).
  • Examples include digestion and cellular respiration.
  • Involves hydrolysis, which requires water.

Major Classes of Macromolecules

1. Carbohydrates:

   • Elements: Carbon (C), Hydrogen (H), Oxygen (O).

   • General formula: (CH₂O)ₙ with a 2:1 ratio of H:O.

   • Monomer: Monosaccharides (e.g., glucose, galactose, fructose).

     • Key Functions:
     • Energy provision and blood glucose regulation.
     • Sparing proteins for energy,
     • Biological recognition processes.

   • Types:

     1. Monosaccharides
     2. Disaccharides
     3. Oligosaccharides
     4. Polysaccharides (e.g., starch, glycogen, cellulose).

2. Lipids:

   • Building Blocks: Glycerol and Fatty Acids.
   • Functions: Energy storage, insulation, building cell membranes, necessary for cell growth.
   • Characteristics: Hydrophobic, non-soluble in water, include fats, phospholipids, and steroids.

3. Proteins:

   • Building Blocks: Amino Acids (20 different types).
   • Functions: Cell renewal/repair, growth, enzyme production, energy supply.
   • Denaturation occurs due to environmental changes (e.g., pH, temperature).

4. Nucleic Acids:

   • Building Blocks: Nucleotides (contains sugar, phosphate, base).
   • Functions: Store hereditary information, guide protein synthesis.
   • Types include DNA and RNA.

Enzymes: Catalysts in Chemical Reactions

• Function of Enzymes: Biological catalysts that speed up reactions by lowering activation energy.

  • Highly specific to their substrates (reactants).
  • Inhibitors decrease enzyme activity while activators increase it.
  • Various factors like temperature, pressure, and pH affect enzyme performance.

• Mechanism:

  • Substrates bind to the enzyme active site, forming products through chemical reactions.
  • Enzymes can undergo changes when substrates bind (induced fit model).
  • Allosteric sites can regulate enzyme activity by allowing the binding of other molecules.

Conclusion

• Understanding the chemistry of life through these various components and reactions is essential for grasping biological processes.