A Lecture Presented by: Mrs. Knopke FUHS Science Dept.

1. Cellular Respiration A Lecture Presented by: Mrs. Knopke FUHS Science Dept.

2. 6O2 + C6H12O6 6CO2 + 6H2O + 36 ATP • This equation summarizes all of the chemical reactions that occur during the process of cellular respiration • Notice that it is the same equation as photosynthesis in reverse • Although proteins, lipids and other carbohydrates can be used to make ATP we use a common source: glucose.

3. Definitions • Reduction: gaining electrons, hydrogen or losing oxygen • Oxidation: Losing electrons, hydrogen or gaining oxygen • Redox (reduction / oxidation) reactions: gain or release chemical energy in a reaction • NAD and FAD: electron hydrogen carrier. Carries them to the Electron Transport chain. When carrying they are called NADH and FADH

4. Review: Oxidation and Reduction • Oxidized atom • Electron is donated • Energy is donated Reduced atom Electron is received Energy is received

5. Review: Oxidation and Reduction Reduced atom Oxidized atom Electron is donated Energy is donated Electron is received Energy is received

6. Why Cellular Respiration? • Cells carry out the reactions of cellular respiration in order to produce ATP. ATP is used by cells for energy • All organisms need energy, therefore all organisms carry out cellular respiration. • The energy needed to produce ATP comes from glucose. As we saw in the previous slides on Photosynthesis were glucose was produced. • 6O2 + C6H12O6 6CO2 + 6H2O + 36 ATP • The reverse of Photosynthesis

7. Comparing Cellular respiration with how a car works! • Introduction • Cars and humans need fuel • Chemical energy used to perform work • Hunger is adaptation to refuel • Fuel for living • All energy comes from the sun • Plants convert solar energy into chemical energy • Sunlight energy • Sun - a giant thermonuclear reactor • Photosynthesis - solar to chemical

10. Phosphorylation: adding a phosphate group to a molecule • Substrate-level phosphorylation: Organic molecule is split or used in conjunction with an enzyme to add a phosphate to ADP to make ATP • Oxidative phosphorylation: Occurs by using an electron transport chain, chemiosomosis and ATP synthase to add a phosphate group

12. The Mitochondria 2 layers of phospholipid Membrane This is where ATP is manufactured!

14. Cells and cars use same basic process • Using potential energy to do work • Breaks bonds to release energy • Cars mix gas with O2 to cause explosion which moves pistons • 25% of potential energy converted to kinetic energy • CO2 and H2O released • Cells do it less explosively • More efficient - 40% potential energy • 60% released as heat energy

15. Fig. 5.6

16. Why do you feel warm in a room at 70 degrees when body temp is 98.6? • Produce heat from cellular respiration • Calorie -1 gram water 1 degree Celsius • Kilocalorie - 1000 calories • Food calories determined by burning food • Measuring how much heat produced • Living organisms use food to make ATP • Adenosine TriPhosphate • Three phosphates have stored energy

17. Fig. 5.7

18. Fig. 5.8

19. ATP used continuously • Recycled continuously • By addition of phosphate group to ADP • Cell respiration used to make ATP • Working muscle cell recycles 10 million per second per cell!

21. Cellular respiration and breathing related but not the same • Breathing in lungs • Intake of O2 • Release of CO2 • Cellular respiration • O2 diffuses into cells • CO2 diffuses out of cells • O2 used to burn food fuel to make ATP • Glucose is common food / fuel • C6H12O6 + 6O2 > > > 6CO2 + 6H2O + ATP

23. Purpose of cellular respiration? • To release energy from food molecules and make ATP! • Why do we need ATP? • To run chemical reactions that keep us alive and functioning.

27. The 4 major steps of Cellular Respiration and their locations • 1) Glycolysis: occurs in cytoplasm • 2) Pyruvate oxidation : at mitochondrian outer membrane • 3) Kreb’s Cycle: mitochondrian matrix • 4) Electron Transport Chain: inner membrane of mitochondria

28. STEP #1 • Glycolysis

29. Glycolysis • 1) Cell Resp. needs an initial 2 molecules of ATP to start • 2) 2 PGALs are intermediate products • 3) 4 NADH , and 4 ATP are produced • 4) 2 Net total of ATP • 5) 2 pyruvic acids are the end products • 6) Oxidative reactions In cytoplasm

31. STEP #2 • Pyruvate Oxidation

32. pyruvate pyruvate Pyruvate Oxidation CO2 NAD NADH • Pyruvate from Glycolysis tries to get into Mitochondria • Too big, must remove a CO2 to fit • CO2 released into atmosphere • NAD takes H’s and e- to E.T.C. • Process uses up 2 ATP • Acetic acid is the end product 2 acetic acid molecules NAD NADH CO2

33. Pyruvate needs to get into mitochondria!

35. STEP #3 Kreb’s Cycle or Citric Acid Cycle

36. Kreb’s Cycle = Citric Acid Cycle 2 acetyl CoA • 2 Acetic Acid molecules imediately bind to a coenzyme called CoA thus making : AcetylCoA • Oxalacetate is the sugar backbone • Citric Acid is a intermediate product • Glucose is obliterated and no carbon is left ADP ATP NAD NADH FAD FADH CO2

38. STEP #4 Electron Transport Chain

39. H+ H+ H+ H+ H+ H+ H+ H+ H+ O- e- ATP Matrix H2O H+ ADP Where are all of the FADH, NADH carriers going? Why did we make them? O2 • 1) To the electron transport chain!! • 2) To make ATP Inner membrane space

40. E.T.C.

41. Cytoplasm inner membrane space H+ H+ H+ H+ H+ H+ H+ H+ H+ H+ O- e- ADP ATP NADH FADH H2O H+ Matrix

42. Overview of all cellular respiration

44. The Numbers • 36 ATP is the net total • 2 ATP in Glycolysis • 2 lost in Pyruvate Oxidation • 3 ATP per NADH in ETC • 2 ATP per FADH in ETC • 4 NADH in Glycolysis • 2 NADH in Pyruvate Oxidation • 4 NADH in Kreb’s Cycle • 3 FADH in Kreb’s Cycle

45. Fermentation or anaerobic respiration • Defined as harvesting energy w/out O2 • Occurs when O2 supply to cells can’t keep up with demand • Spending more ATP than can be generated by aerobic respiration • Glycolysis still runs but Krebs cycle can’t • How much ATP does glycolysis make? • Not much compared to aerobic respiration

46. What if there is no oxygen to drive the electron transport chain in cellular respiration? • Organisms still need ATP to survive! The Answer: Anaerobic Respiration Fermentation

47. Fermentation: A type of anaerobic respiration

48. Lactic Acid: In our muscles Alcoholic: In yeast cells

49. Lactic acid Fermentation • Animals use this anaerobic process • Get some ATP profit • NADH is recycled to NAD+ • To keep glycolysis running • End product lactic acid • Makes muscles sore • Only a short term solution • Lactic acid converted back to pyruvic acid in liver cells when O2 is available • Oxygen debt repaid by breathing hard