Inside the Cell Notes

Inside the Cell Notes

Microscope History

  • Van Leeuwenhoek: First to describe small organisms (animalcules) using a microscope.
  • Hooke: First to sketch and name cells.

Cell Theory (1839)

  • Schleiden & Schwann:
    • All organisms consist of one or more cells.
    • New cells arise from existing cells.
    • The cell is the basic unit of structure and organization.

Cell Characteristics

  • Common Features of All Cells:
    • Plasma membrane
    • Cytoplasm
    • DNA
  • Types of Cells:
    • Eukaryotic: Contains nucleus and organelles.
    • Prokaryotic: Lacks nucleus and organelles, has circular DNA.

Prokaryotic vs. Eukaryotic Cells

  • Prokaryotic: Smaller, simpler (Bacteria and Archaea).
  • Eukaryotic: Complex, including plant and animal cells.

Eukaryotic Plant Cell Organelles:

  • Cell Wall: Provides structure and protection.
  • Chloroplast: Site of photosynthesis.
  • Central Vacuole: Stores metabolic wastes.
  • Nucleus: Contains DNA; controls access; produces ribosomes.
  • Mitochondria: Energy production (ATP).
  • Plasma Membrane: Selectively permeable barrier.
  • Ribosomes: Site of protein synthesis.
  • Endoplasmic Reticulum (ER): Rough (modifies proteins) and Smooth (lipid synthesis, detoxification).
  • Golgi Body: Packages and ships proteins and lipids.

Eukaryotic Animal Cell Organelles:

  • Similar to plant cells, with:
    • Centrioles: Organize microtubules.
    • Lysosomes: Digests and recycles materials.

Cell Membrane Structure

  • Lipid Bilayer: Phospholipids with hydrophilic heads and hydrophobic tails.
  • Fluid Mosaic Model: Membranes composed of varied proteins and lipids that allow fluid movement.

Organelles Overview

  • Nucleus: Protects DNA, regulates gene expression.
  • Endomembrane System: Includes nuclear envelope, ER, Golgi apparatus, and vesicles.

Energy-Related Organelles

  • Mitochondria: ATP production, aerobic respiration, double membrane structure.
  • Chloroplasts: Site of photosynthesis, converts sunlight to energy.

Cytoskeleton Functions

  • Maintains cell shape, allows movement, and transports organelles.

Cilia and Flagella

  • Composed of microtubules, responsible for cell movement; cilia are shorter and more numerous.

Extracellular Matrix (Animal Cells)

  • Composed of fibrous proteins (e.g., collagen, elastin) that provide structural support.

Cell Junctions in Animal Cells

  • Types:
    • Adhesion Junctions: Attach cytoskeletons of adjacent cells.
    • Tight Junctions: Prevent leakage between cells.
    • Gap Junctions: Allow communication between cells, important in muscle tissues.