GCSE Biology - Cell Biology Notes

GCSE Biology - Cell Biology Notes

1. Cell Structure

  • Definition: All living organisms are made of cells.
  • Types of Cells:
    • Eukaryotic Cells: Found in animals and plants.
    • Prokaryotic Cells: Found in bacteria.

2. Animal Cell Parts and Functions

  • Nucleus:

    • Function: Controls activities of the cell and contains DNA.

  • Cytoplasm:

    • Function: Where most chemical reactions take place.

  • Cell Membrane:

    • Function: Controls the movement of substances in and out of the cell.

  • Mitochondria:

    • Function: Site of aerobic respiration, where energy is produced.

  • Ribosomes:

    • Function: Site of protein synthesis, where proteins are assembled from amino acids.

3. Plant Cell Additional Parts

  • Cell Wall:

    • Composition: Made of cellulose.
    • Function: Provides support to the cell.

  • Chloroplasts:

    • Function: Contains chlorophyll, essential for photosynthesis, allowing plants to convert sunlight into energy.

  • Permanent Vacuole:

    • Function: Contains cell sap, helping to maintain pressure within the cell and providing structural support.

4. Microscopes

  • Light Microscopes:

    • Characteristics: Use light and lenses to magnify specimens.

  • Electron Microscopes:

    • Characteristics: Offer higher magnification and resolution compared to light microscopes, allowing for detailed observation of small structures.

5. Magnification Calculation

  • Formula: Magnification = Image size / Real size.

6. Diffusion

  • Definition: Movement of particles from an area of high concentration to an area of low concentration.
  • Characteristics:
    • Passive process (does not require energy).
    • The speed of diffusion increases with higher temperatures.

7. Osmosis

  • Definition: Movement of water across a partially permeable membrane from an area of high water concentration to an area of low water concentration.

8. Active Transport

  • Definition: Movement of particles against their concentration gradient.
  • Requirements: Requires energy derived from respiration.

9. Mitosis

  • Definition: Process of cell division essential for growth and repair.
  • Outcome: Produces two identical daughter cells, ensuring genetic consistency.

10. Stem Cells

  • Definition: Undifferentiated cells that have the potential to become specialized cell types.
  • Locations: Found in embryos, bone marrow, and certain plants, enabling tissue growth and repair.