Introduction to Biochemistry Lecture Notes

Jul 16, 2024

Introduction to Biochemistry

What is Biochemistry?

  • Study of cells: their composition and functioning.
    • Enzymes used by cells
    • Formation and use of amino acids
    • Interaction with the body (e.g., breathing, perspiration)
  • Importance:
    • Solutions to diseases (e.g., AIDS, HIV, sickle cell anemia)
    • Example: PrEP medication for HIV

Course Philosophy

  • Instructor is not affiliated with the TA or professor
  • Offers the lectures for student benefit
  • Honest and thorough explanations promised
  • Encourages a respectful and collaborative learning experience

Eukaryotic Cells

Basics

  • Eukaryotic cells: have multiple organelles (e.g., Golgi complex, nucleus, mitochondrion)
  • Size: 10 to 100 nanometers in diameter (10x larger than prokaryotic cells)
  • Found in plants, animals, protozoa

Plasma Membrane

  • Functions as a chemical barrier
  • Made of lipids and proteins

Compartmentalization

  • Organelles perform specific functions within compartments
  • Allows for efficient biological processes

Differences Between Animal and Plant Cells

  • Animals: no cell walls, have plasma membrane
  • Plants: have cell walls

Parts of the Cell

Cytoplasm

  • Thick, aqueous environment within the plasma membrane
  • Contains concentrated protein (20-30% of cytoplasm)
  • Major site for cellular metabolism (e.g., glycolysis)

Cytoskeleton

  • 3D matrix made of protein fibers
  • Provides cell shape, movement, and guides internal organelle movement

Nucleus

  • Largest part of the cell
  • Stores genetic information, makes DNA and RNA
  • Bound by a double membrane

Endoplasmic Reticulum (ER)

  • Network of interconnected, membrane-bound vesicles
  • Two types:
    • Smooth ER: makes lipids (fats)
    • Rough ER: makes proteins via ribosomes
  • Attaches to the nuclear membrane
  • Functions: make, change, and transport cellular materials

Ribosomes

  • Made of RNA and protein
  • Not membrane-bound
  • Found in ER, synthesizes proteins

Lysosomes

  • Acts as waste disposal system
  • Very acidic (pH ~5)
  • Enzymes degrade polymers into monomers

Golgi Complex

  • Flattened vesicles of lipids, proteins, and sugars
  • Processes proteins and fats
  • Distributes cell materials to other organelles

Mitochondria

  • Known as the powerhouse of the cell
  • Has inner and outer membrane
  • Performs oxidative energy production, makes ATP
  • Contains circular DNA and its own genome
  • Possibly a descendant of a bacterial symbiont (Endosymbiotic Hypothesis)
  • Crucial in muscle cells for energy production