1. Introduction Overview of respiration and photosynthesis (Freeman Chp 9) Origins of mitochondrion and chloroplast Interdependence of photosynthesis and respiration 1

2. Respiration – occurs in cytoplasm & specialised mitochondria Double membrane bound Internal membranes form cristae Inner membrane contains the active mitochondrial matrix Contain its own chromosome – All genes occur on a single DNA molecule Divides independently from rest of cell 1

3. cytoplasm mitochondrion Complex carbohydrates O 2 CO 2 + water Energy 1

4. cytoplasm mitochondrion Complex carbohydrates O 2 CO 2 + water Energy 1 Sir Hans Adolf Krebs (1900-1981), proposed the key elements of this pathway in 1937 and was awarded the Nobel Prize in Medicine in 1953.

5. cytoplasm mitochondrion Complex carbohydrates O 2 CO 2 + water Energy 1

6. Photosynthesis – occurs in chloroplasts Has: Double membrane Internal membrane system – thylakoids Contains its own chromosomal material Divides independently from rest of cell 1

7. CO 2 + water O 2 Complex carbohydrates Energy Thylakoid membranesStroma 1

8. CO 2 + water O 2 Complex carbohydrates Energy Thylakoid membranesStroma 1 Calvin and Benson

9. How did the chloroplast and mitochondrion originate? “Endosymbiosis theory” Origin of Mitochondrion  Protoeukaryote ingested smaller aerobic bacteria by phagocytosis.  Protoeukaryote were anaerobic depended on glycolysis for energy (glucose  pyruvate, produced 2 ATP)  Aerobic bacteria had electron transport and oxidative phosphorylation (glucose  CO 2, produced 32 ATP)  Host protoeukaryote provided protection and nutrients  Over 100s of millions of years bacteria lost non-essential functions and developed into the mitochondrion.  Mitochondria contain DNA and RNA and rRNA shows closest match to purple bacteria. 1

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14. Origin of Chloroplast  Eukaryote already with primitive mitochondria ingested primitive photosynthestic bacteria.  Photosynthetic bacteria lost unnecessary functions to evolve into chloroplasts.  rRNA from chloroplasts shows closet match to cyanobacteria  Other rRNA unlike cyanobacteria suggests multiple origins 1

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16. Paramecium bursa 1 See Chpt 28

17. O2O2 Food CO 2 H2OH2O Photosynthesis Respiration Heat Work 1

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