Cell Theory and Transport Mechanisms

Key Concepts

• Cell Theory: States that cells are alive; single-cell organisms demonstrate life.
• Homeostasis: Cells maintain homeostasis by moving objects in and out.

Transport Mechanisms

• Diffusion:

  • Movement of particles from high concentration to low concentration.
  • Does not require energy.
  • Example: Oxygen and carbon dioxide.
  • Cell membrane, composed of a phospholipid bilayer, allows simple diffusion.

• Facilitated Diffusion:

  • Uses channels or proteins to assist particle movement.
  • Particles still move from high to low concentration.
  • No energy required.
  • Example: Glucose transport using carrier proteins.

• Active Transport:

  • Moves particles against the concentration gradient (low to high).
  • Requires energy in the form of ATP.
  • Types of Active Transport:
    • Membrane Pumps:
      • Example: Sodium-Potassium pump.
      • Moves sodium out and potassium into the cell using ATP.
    • Vesicle Movement:
      • Endocytosis: Brings large objects into the cell.
        • Phagocytosis: Ingests solids.
        • Pinocytosis: Ingests liquids.
        • Receptor-Mediated Endocytosis: Targets specific molecules using receptors.
      • Exocytosis: Expels objects out of the cell.

Additional Information

• Phospholipid Bilayer:
  • Composed of two layers with polar heads and non-polar tails.

Resources

• For more on active transport, refer to the suggested playlist.

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Note: This summary covers the key points from MooMooMath and Science's lecture on cell transport mechanisms and cell theory.