Chapter 9: Cellular Respiration

1. Chapter 9: Cellular Respiration How do cells use food (glucose) to make energy (ATP)?

2. http://www.teachersdomain.org/resource/tdc02.sci.life.cell.mitochondria/http://www.teachersdomain.org/resource/tdc02.sci.life.cell.mitochondria/ • http://www.teachersdomain.org/resource/tdc02.sci.life.cell.stetteroxygen/

3. Cellular Respiration • The process that releases energy by breaking down food molecules in the presence of oxygen • C6H12O6 + 6O2 6H2O + 6CO2 + Energy

4. Batteries of Life • Adenosine Triphosphate – ATP • Adenosine Diphosphate – ADP

5. ATP Adenine (base) Ribose (sugar) 3 Phosphate groups

6. Figure 8-3 Comparison of ADP and ATP to a Battery ADP ATP Energy Energy Adenosine diphosphate (ADP) + Phosphate Adenosine triphosphate (ATP) Partially charged battery Fully charged battery

7. Figure 8-3 Comparison of ADP and ATP to a Battery ADP ATP Energy Energy Adenosine diphosphate (ADP) + Phosphate Adenosine triphosphate (ATP) Partially charged battery Fully charged battery

8. NADH – another energy carrying molecule (electron bus) • NAD+ + H+ + 2e- NADH Energy carrierenergystored energy • NADH NAD+ + H+ + 2e- Stored energyEnergy carrierreleased energy

9. FADH2 – another energy carrying molecule • FAD + H2+ + 2e- FADH2 Energy carrierenergystored energy • FADH2 FAD + H2+ + 2e- Stored energyEnergy carrierreleased energy

10. Full Charged (Stored Energy) ATP NADH FADH2 Partially Charged (Energy Released from Carriers) ADP NAD+ FAD Comparing them all to batteries…

11. Cellular Respiration=3 Steps When Oxygen is Present • Glycolysis • Krebs Cycle • Electron Transport Chain

12. Chemical Pathways Glucose Krebs cycle Electrontransport Glycolysis Alcohol or lactic acid Fermentation (without oxygen)

13. Figure 9–2 Cellular Respiration: An Overview Mitochondrion Electrons carried in NADH Electrons carried in NADH and FADH2 Pyruvic acid Glucose Electron Transport Chain Krebs Cycle Glycolysis Mitochondrion Cytoplasm

14. Glycolysis (anaerobic) • Glucose broken into 2 molecules of Pyruvic Acid • Oxygen not required • 2 ATP are used and 4 ATP and 2 NADH are produced (full charged batteries) • Net gain of 2 ATP • Occurs for a short time because NAD+ molecules fill up with electrons quickly • Takes place in cytoplasm

15. Figure 9–3 Glycolysis Glucose 2 Pyruvic acid To the electron transport chain

16. Figure 9–3 Glycolysis Section 9-1 Glucose 2 Pyruvic acid To the electron transport chain

17. Figure 9–3 Glycolysis Glucose 2 Pyruvic acid To the electron transport chain

18. Krebs Cycle (aerobic) • When O2 is present, pyruvic acid from glycolysis produces CO2, ATP, NADH and FADH2 (full charged batteries). • 1 molecule of Glucose produces 2 turns of the cycle • Takes place in mitochondria

19. Figure 9–6 The Krebs Cycle Citric Acid Production Mitochondrion

20. Figure 9–6 The Krebs Cycle Citric Acid Production Mitochondrion

21. Electron Transport Chain (aerobic) • NADH and FADH2 made in glycolysis and the Krebs Cycle are used to make ATP • Uses high energy electrons to convert ADP into ATP (passes them down the chain) • Oxygen accepts electrons last (at end of chain) so they are low energy. O also accepts H+ ions to form water as waste product. • Energy from electrons used to get H across membrane • ATP produced when H+ transported across membrane • Take place in mitochondria

22. Figure 9–7 Electron Transport Chain Electron Transport Hydrogen Ion Movement Channel Mitochondrion Intermembrane Space ATP synthase Inner Membrane Matrix ATP Production

23. What does 1 molecule of glucose produce? • 36 ATP (2 from glycolysis and 34 from Krebs Cycle and Electron Transport Chain) • 38% of total available from glucose • 62% produces heat • increased temp. during sports • natural warmth (winter)

24. What happens when O2 isn’t available? • Fermentation • 2 Types • occurs after glycolysis in cytoplasm • anaerobic- without oxygen • Alcoholic Fermentation • Lactic Acid Fermentation

26. Alcoholic Fermentation-forms ethyl alcohol and CO2 as products

27. Baking • Yeasts during this process (alcoholic fermentation) release carbon dioxide which causes bread to rise (only happens when oxygen runs out) • The other product, alcohol, fortunately evaporates while baking!

28. Lactic Acid Fermentation-forms lactic acid as product

29. Figure 9–4 Lactic Acid Fermentation Lactic acid Glucose Pyruvic acid

30. Figure 9–4 Lactic Acid Fermentation Lactic acid Glucose Pyruvic acid

31. Figure 9–4 Lactic Acid Fermentation Lactic acid Glucose Pyruvic acid

32. The Burn • Large muscles that run out of oxygen quickly build up lactic acid which causes a painful burning sensation.

33. Quick Energy - Anaerobic • Glycolysis provides 4 seconds of ATP in the cell • Exercise for 5 seconds - 90 seconds - Lactic Acid Fermentation (approx. 300 m sprint is max) • Oxygen debt and Heavy Breathing • Anaerobic training builds up glycogen (a polysaccharide) in the muscles and develops lactic acid tolerance

34. Long-Term Energy - Aerobic • Cellular Respiration required after 90 seconds • Glycogen during the first 15-20 minutes • Fats after 20 minutes • Aerobic activity increases the size and number of mitochondria and increase oxygen delivery by improving the heart and lungs

36. Creatine • Creatine Phosphate donates a phosphate to ADP to make more ATP • Prolongs the 4 seconds before lactic acid fermentation • Allows for more repetitions and more intense workouts • If abused could lead to kidney and liver problems