Endosymbiotic Theory

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Endosymbiotic Theory

• p. 427-428

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The Endosymbiotic Theory

• Review
• What is a theory?
• What is the difference between prokaryotic and
  eukaryotic cells?
• The endosymbiotic theory is the idea that a long
  time ago, prokaryotic cells engulfed other
  prokaryotic cells by endocytosis. This resulted
  in the first eukaryotic cells.
• First proposed by Lynn Margulis
• Explains the origin of eukaryotic cells
• Explains the origin of certain membrane-bound
  organelles

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What Exactly Happened?
Chloroplast
Plants and plant-like protists
Ancient Prokaryotes
Heterotrophic bacteria
Photosynthetic bacteria
Nuclear envelope evolving
Mitochondrion
Primitive Autotrophic (Photosynthetic) Eukaryote
Animals, fungi, and animal-like protists
Ancient Heterotrophic Prokaryote
Primitive Heterotrophic Eukaryote
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Membrane-Bound Organelles

• Mitochondria membrane-bound organelle that
  produces energy for the cell
• Chloroplast membrane-bound organelle that
  captures sunlight and uses it to make food for
  the cell

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Evidence in support of the endosymbiotic theory

• Similarities between mitochondria, chloroplasts,
  prokaryotes
• Circular DNA
• Ribosomes
• Binary fission