Chapter: Biomolecules

• Introduction to Biomolecules

  • Definition of Cellular Pool
  • Inorganic vs Organic constituents
  • Analysis of chemical composition (Acid-soluble vs Acid-insoluble fractions)

• Primary and Secondary Metabolites

  • Primary Metabolites
    • Identifiable functions
    • Known roles in physiological processes
    • Examples: Amino acids, sugars
  • Secondary Metabolites
    • Ecological importance
    • Examples:
      • Pigments (Carotenoids, Anthocyanins)
      • Alkaloids (Morphine, Codeine)
      • Terpenoids (Monoterpenes, Diterpenes)
      • Essential oils (Lemon grass oil)
      • Toxins (Abrin, Ricin)
      • Lectins, Drugs, Polymeric substances

• Biomacromolecules

  • General characteristics (Molecular weight > 1000 Da)
  • Proteins
    • Polymers of amino acids
    • Peptide bond formation
    • Structures: Primary, Secondary, Tertiary, Quaternary
    • Biological roles (Enzymes, Transport, Hormones)
  • Polysaccharides
    • Long chains of sugars (Glycosidic bonds)
    • Homopolysaccharides (Cellulose, Starch, Glycogen)
    • Heteropolysaccharides (Inulin, Chitin)
  • Nucleic Acids
    • Polymers of nucleotides
    • Components: Nitrogenous base, Pentose sugar, Phosphate group
    • Types: DNA (Deoxyribonucleic acid) and RNA (Ribonucleic acid)

• Lipids

  • Molecular weight generally < 800 Da (found in acid-insoluble fraction)
  • Simple lipids (Fatty acids + Glycerol) -> Fats and Oils
  • Phospholipids (Cell membrane components)
  • Derived lipids (Cholesterol)

• Proteins (Detailed Structure)

  • Amino Acids
    • Structure: Central carbon, amino group, carboxyl group, hydrogen, R group
    • Classification: Acidic, Basic, Neutral, Aromatic
    • Essential vs Non-essential amino acids
    • Zwitterionic form

• Enzymes (Biocatalysts)

  • Chemical nature (mostly proteins, some are ribozymes)
  • Properties
    • Catalytic power
    • Specificity
    • Reversibility
  • Factors affecting activity
    • Temperature
    • pH
    • Concentration of substrate
    • Inhibition (Competitive and Non-competitive inhibitors)
  • Classification and Nomenclature (EC numbers)
    • Oxidoreductases
    • Transferases
    • Hydrolases
    • Lyases
    • Isomerases
    • Ligases
  • Co-factors
    • Prosthetic groups
    • Co-enzymes
    • Metal ions