Exciting Day in Science Class

• Memorable Experiences
  • Earthworm dissection
  • Owl pellet dissection
  • Osmosis eggs experiment
  • Genetic experiments with fruit flies
  • Key Experience: Observing an amoeba in pond water during ninth grade
    • Fascination with the single-celled organism
    • Reflection on cellular composition in humans

Modern Cell Theory

1. Smallest Living Unit: The cell is the smallest living unit in all organisms.
2. All Living Things: All living things are made of one or more cells.
   • Unicellular Organisms: Example: Amoeba (single-celled)
   • Multicellular Organisms: Example: Humans (many cells)
3. Cell Division: All cells come from pre-existing cells.

Cells Classification

• Types of Cells:
  • Prokaryotes:
    • Examples: Bacteria and Archaea
    • No nucleus or membrane-bound organelles
  • Eukaryotes:
    • Examples: Plants, animals, fungi, protists
    • Have a nucleus and membrane-bound organelles

Cell Components

• Similarities between Prokaryotes and Eukaryotes:

  • Genetic material
  • Cytoplasm
  • Ribosomes
  • Cell membrane

• Differences:

  • Prokaryotes: No nucleus, no membrane-bound organelles
  • Eukaryotes: Nucleus and membrane-bound organelles present

Inside the Cell

• Cell Membrane:
  • Selectively permeable; maintains homeostasis
• Cytoplasm: Jelly-like material found in both types of cells
• Cytoskeleton:
  • Provides support and aids in cell movement

Organelles in Eukaryotic Cells

• Ribosomes:
  • Not membrane-bound; make proteins
  • Can be free-floating or attached to the rough ER
• Nucleus:
  • Houses genetic material (DNA)
  • Controls cell activities; contains the nucleolus (produces ribosomes)
• Endoplasmic Reticulum (ER):
  • Rough ER: Has ribosomes, involved in protein production and transport
  • Smooth ER: Involved in detoxification and lipid production
• Golgi Apparatus:
  • Packaging center for proteins and molecules; modifies and sorts materials
• Mitochondria:
  • Powerhouse of the cell; produces ATP energy through cellular respiration

Differences between Animal and Plant Cells

• Chloroplasts:
  • Found in plant cells; perform photosynthesis
• Vacuoles:
  • Plant cells have a central vacuole; animal cells have smaller, multiple vacuoles
• Cell Wall:
  • Additional protective layer in plant cells, not found in animal cells

Summary of Protein Synthesis

• Process:
  1. Instructions from DNA in the nucleus
  2. Ribosome synthesizes protein
  3. Rough ER packages proteins into vesicles
  4. Golgi apparatus sorts and sends proteins to the membrane for secretion

Conclusion

• Encouragement to explore more about cells and their organelles
• Reminder to stay curious!