Endosymbiotic Theory Lecture Notes

Introduction

• Presenter: Kathy from Love Larn
• Focus: Endosymbiotic theory
• Includes a quiz at the end
• Recommended tool: Level Up RN Microbiology flashcards

Endosymbiotic Theory Overview

• Concept: Explains the evolution of mitochondria and chloroplasts from prokaryotic cells.
  • Mitochondria: Organelles where aerobic cellular respiration occurs.
  • Chloroplasts: Organelles in plant and algae cells where photosynthesis takes place.

Mechanism of Endosymbiotic Theory

• Mitochondria Development:
  • Originated from a bacterium capable of aerobic respiration.
  • Incorporated into a eukaryotic cell via phagocytosis.
  • Remained as an intracellular component.
• Chloroplast Development:
  • Originated from a photosynthetic bacterium.
  • Incorporated into a eukaryotic cell via phagocytosis.
  • Remained as an intracellular component.

Evidence Supporting Endosymbiotic Theory

1. DNA Structure:
   • Mitochondria and chloroplasts have circular DNA, similar to prokaryotic cells.
   • Eukaryotic cells have linear DNA.
2. Ribosome Type:
   • Mitochondria and chloroplast contain 70S ribosomes, similar to prokaryotic ribosomes.
   • Eukaryotic cells have 80S ribosomes.
3. Size:
   • Mitochondria and chloroplasts are small, like prokaryotic cells.
   • Eukaryotic cells are larger.
4. Division Process:
   • Mitochondria and chloroplasts divide by binary fission, like prokaryotes.
   • Eukaryotic cells divide by mitosis.
5. Membrane Composition:
   • Mitochondria and chloroplasts have a double membrane.
   • Inner membrane similar to prokaryotic plasma membrane.
   • Outer membrane similar to eukaryotic plasma membrane.
   • Suggests initial phagocytosis incorporated the host cell membrane.

Quiz

1. Question: Which two organelles in eukaryotic cells are explained by the endosymbiotic theory?
   • Answer: Mitochondria and chloroplasts.
2. Question: How do chloroplast ribosomes support the endosymbiotic theory?
   • Answer: Chloroplast ribosomes are 70S, similar to prokaryotic ribosomes.
3. Question: True or False: The inner membrane of mitochondria is similar to the plasma membrane of a eukaryotic cell.
   • Answer: False. It is similar to the plasma membrane of a prokaryotic cell.

Conclusion

• Encouragement to study and share the video
• Call to subscribe and like the video if found helpful.