1. CELLULAR RESPIRATION and FERMENTATION

2. Energy Harvest Fermentation – partial breakdown w/o oxygen Cellular Respiration – most efficient, oxygen consumed, mitochondria Cells recycle ATP Redox reactions (oil/rig); reducing agent – electron donor; oxidizing agent – acceptor Cell Resp: glucose oxidized – H removed; oxygen reduced – accepts H

3. ATP – adenosine triphosphate

4. ATP CYCLE ATP + H 2 0 ↔ ADP + P i + energy

5. Energy flow and chemical recycling in ecosystems

6. NAD + electron shuttle Nicotinamide adenine dinucleotide Coenzyme, oxidizing agent, reduced form NADH NADH shuttles electrons to ETC

7. ETC – proteins, cytochromes in cristae, series of smaller steps, stores released energy to make ATP, oxygen combines w/ electrons and proton

8. Glycolysis glucose  pyruvate; cytosol

9. Krebs cycle mitochondrial matrix, pyruvate  acetyl CoA & CO 2

11. PHOSPHORYLATION OXIDATIVE –ATP synthesis powered by redox reactions –Electron transport chain –Requires oxygen (final electron acceptor) SUBSTRATE LEVEL –ATP synthesis from transfer of phosphate group from substrate to ADP –Glycolysis and Krebs cycle

12. Substrate level Phosphorylation in glycolysis

13. GLYCOLYSIS Splitting of glucose C 6 H 12 O 6 → 2 C 3 H 3 O 3 Uses 2 ATP’s Makes 4 ATP’s Net 2 ATP’s 2 NADH & 2 H + ← SUMMARY

14. GLYCOLYSIS Glucose → 2G3P → 2 PGA → 2 pyruvates ↑ ↑ ↑ requires 2 NAD + generates 2 ATP’s reduced 4 ATP’s 2 NADH

15. Oxidation of Pyruvate Occurs in mitochondrion, requires transport protein & coenzyme A Yields Acetyl CoA, 1 NADH & 1 H + from each pyruvate (2 total) Waste – carbon dioxide

17. KREBS CYCLE Occurs in mitochondrial matrix 1 cycle/pyruvate 2 cycles/glucose Acetyl CoA (2-C) + oxaloacetate (4-C) → citrate (6-C) 7 more steps: 2CO 2 removed, 3NADH & H +, 1FADH 2 1 ATP – substrate phosphorylation

19. Oxaloacetate 4-C Citrate 6-C

21. ELECTRON TRANSPORT Cristae of mitochondrion – foldings ↑ surface area Electron carriers (proteins) embedded in membrane NADH “delivers” electrons to first molecule in chain (3 ATP’s); FADH 2 adds electrons at lower level (2 ATP’s) Last cytochrome passes electrons to ½O 2 + H 2 → H 2 O

22. CHEMIOSMOSIS Energy coupling ATP synthase  Generates ATP  Molecular mill  Powered by proton flow Uses exergonic flow of electrons to pump H + (protons) from matrix into intermembrane space, they flow back through ATP synthase H + gradient couples redox reactions of ETC to ATP synthesis

25. SUMMARY

27. FERMENTATION Anaerobic glycolysis followed by break down of pyruvates Substrate level phosphorylation Regenerates NAD + from NADH Alcoholic: yeast, bacteria, produces – 2 ATP, 2 CO 2 & 2 ethanol from pyruvates Lactic acid: fungi, human muscle cells, bacteria, produces – 2 ATP & 2 lactates from pyruvate Acetic acid: bacteria, 2 ATP, 2 CO 2 & 2 acetic acids from pyruvates

32. Fermentation vs Respiration Both oxidize glucose in glycolysis Pyruvate & 2 ATP’s NAD + accepts electrons Key difference: Oxidation of NADH (NAD + required to sustain glycolysis) Final e- acceptor (organic molecule vs O 2 ) 2 ATP’s vs 38 ATP’s

33. Facultative anaerobes Yeast Bacteria Human muscle cells Evolutionary significance of glycolysis?

35. Other metabolic pathways Versatility of catabolism Biosynthesis Anabolic pathways may use intermediates & consume ATP

37. FEEDBACK MECHANISMS CONTROL CELLULAR RESPIRATION