Lecture Notes: Introduction to Cells and Their Organelles

Introduction

• Exciting Science Experiences: Mention of memorable science class experiences such as earthworm dissection, owl pellet examination, osmosis eggs, and fruit fly experiments.
• Influence of Amoebas: Seeing an amoeba in a 9th-grade class sparked a passion for science.

Modern Cell Theory

• Three Key Statements:
  1. The cell is the smallest living unit in all organisms.
  2. All living things are made of one or more cells (unicellular and multicellular organisms).
  3. All cells come from pre-existing cells.

Types of Cells

• Prokaryotes vs. Eukaryotes
  • Prokaryotes:
    • Include Bacteria and Archaea.
    • No nucleus or membrane-bound organelles.
  • Eukaryotes:
    • Include plants, animals, fungi, and protists.
    • Have a nucleus and membrane-bound organelles.

Common Features of All Cells

• Genetic Material: Present in both types of cells.
• Cytoplasm: Jelly-like substance surrounding organelles.
• Ribosomes: Organelles that make proteins.
• Cell Membrane: Selectively permeable, maintains homeostasis.

Organelles in Eukaryotic Cells

• Nucleus:
  • Contains genetic material (DNA).
  • Controls cell activities.
  • Contains nucleolus where ribosomes are produced.
• Endoplasmic Reticulum (ER):
  • Rough ER with ribosomes (involved in protein production and transport).
  • Smooth ER (involved in detoxification and lipid production).
• Golgi Apparatus:
  • Packages, modifies, and sorts molecules.
  • Determines molecule destination, possibly secretion.
• Mitochondria:
  • Powerhouse of the cell, produces ATP energy through cellular respiration.
• Chloroplasts (in plant cells only):
  • Conducts photosynthesis, converting light energy into glucose.

Differences between Plant and Animal Cells

• Vacuoles:
  • Plant cells have a large central vacuole.
  • Animal cells have smaller vacuoles.
• Cell Wall (in plant cells only):
  • Provides additional protection and shape maintenance.

Protein Creation and Secretion Pathway

• Process:
  1. Instructions from DNA in the nucleus.
  2. Ribosome production on Rough ER.
  3. Transport via vesicle to Golgi apparatus for sorting.
  4. Secretion via vesicle to cell membrane.

Conclusion

• Encouragement to explore more about organelles and stay curious.