Understanding Proteins and Biomolecules

Sep 5, 2024

Lecture Notes: Proteins and Related Biomolecules

Overview of Proteins

  • Found in: Meat and legumes
  • Composition: Carbon, oxygen, hydrogen, nitrogen, and some sulfur
  • Role: Construction materials for the body; body's workers
  • Properties: Hydrophilic, dissolve in water

Amino Acids and Protein Structure

  • Building Blocks: 20 amino acids
    • 8 essential amino acids (must be obtained from diet)
  • Polypeptides: Chains of up to 50 amino acids
    • Longer chains are proteins
  • Structure Levels:
    • Primary Structure: Sequence of amino acids
    • Secondary Structure: Hydrogen bonds form shapes like helix or pleated sheets
    • Tertiary Structure: 3D folds due to hydrogen and covalent bonds
    • Quaternary Structure: Combination of multiple tertiary structures (e.g., hemoglobin)
  • Function: Specific to protein's amino acid sequence

Types of Proteins

  • Fibrous Proteins: Structural
    • Provide strength, e.g., collagen, keratin
    • Tendons, skin, hair, nails
  • Globular Proteins: Functional
    • Compact, spherical
    • Include antibodies, hormones, enzymes
    • More delicate compared to fibrous proteins

Enzymes

  • Role: Biological catalysts
  • Function: Increase reaction rate, do not become part of products
  • Active Sites: Bind reacting molecules, assist in breaking/making bonds
  • Specificity: Shape determines function
  • Naming: Often ends in "-ase" (e.g., hydrolysis, oxidases)
  • Inactive Forms: Often produced in inactive forms (e.g., pepsinogen)

Nucleic Acids

  • Types: DNA, RNA
  • Function: Genetic material, blueprint for proteins
  • DNA Structure: Double helix
    • Nucleotides: Adenine, thymine, guanine, cytosine
    • Complementary base pairs: A-T, G-C
  • RNA: Single-strand, involved in protein synthesis
    • Uracil replaces thymine

ATP (Adenosine Triphosphate)

  • Role: Energy molecule of the body
  • Structure: Adenosine with three phosphates
  • High-Energy Bonds: Release energy when broken
  • ATP to ADP: Energy release through hydrolysis
  • Recharging: Phosphates reattached using energy from food oxidation

Conclusion

  • Next topic: Cells
  • Break before continuing