Cellular respiration: Part 2 Kreb Cycle

1. Cellular respiration: Part 2 Kreb Cycle

2. outer membrane intermembrane space inner membrane cristae matrix mitochondrialDNA Mitochondria — Structure • Double membrane energy harvesting organelle What cells would have a lot of mitochondria?

3. Oooooh!Form fits function! Mitochondria – Function Dividing mitochondria Who else divides like that? Membrane-bound proteins Enzymes & permeases Advantage of highly folded inner membrane? What does this tell us about the evolution of eukaryotes?

4. NAD+ Pyruvate oxidized to Acetyl CoA reduction Acetyl CoA Coenzyme A CO2 Pyruvate C-C C-C-C oxidation • Acetyl CoA enters Krebs cycle

5. 1937 | 1953 Citric Acid cycle • aka Krebs Cycle • in mitochondrial matrix • 8 step pathway • Evolved later than glycolysis • does that make evolutionary sense? • bacteria 3.5 billion years ago (glycolysis) • free O22.7 billion years ago (photosynthesis) • eukaryotes 1.5 billion years ago (aerobic respiration = organelles  mitochondria) Hans Krebs 1900-1981

6. Whassup? What’s the point?

7. 4 NAD+1 FAD 4 NADH+1FADH2 2x 1C 3x 1 ADP 1 ATP Energy accounting of Citric Acid cycle pyruvate          CO2 3C ATP

8. How is the CAC thermodynamically favoured? • 1st Law: Energy is not created or destroyed • 2nd Law: There is an increase in entropy in the universe

9. Value of Citric Acid cycle? • If the yield is only 2 ATP then how was the Citric Acid cycle an adaptation? like $$in the bank

10. 2 Methods of Generating ATP • Substrate Level Phosphorylation • Chemiosmotic Generation of ATP

11. Substrate Level Phosphorylation

12. Substrate Level Phosphorylation

13. Chemiosmosis

14. OXIDATIVE PHOSPHORYLATION

15. e- e- e- e- e- e- H+ H+ H+ H+ H+ H+ Q C 0 + 2H+ = H2O NAD+ H+ ADP + Pi ATP

16. H+ NADH + H+ QH2 ATP synthase NADH-Q reductase Cytochrome b, c1 Cytochrome c oxidase NAD+ Q oxidized cytochrome c Succinate Q reductase ADP + Pi ATP ½ O2 H2O H+ FADH2 FAD+ oxidation reduction FADH2 modification