Breathing and Cellular Respiration

1. Breathing and Cellular Respiration

2. INTRO • Fast and slow twitch muscles

3. LONG DISTANCE RUNNING Slow-twitch fibers for repeated long contractions SPRINTING or WEIGHT LIFTING Fast-twitch fibers Contract more quickly and powerfully What kind of runner are you?

4. SLOW TWITCH breaks down glucose to get ATP AEROBICALLY (using oxygen) FAST TWITCH breaks down glucose to get ATP ANAEROBICALLY(not using oxygen) What makes these muscle fibers so different?

5. 1. Thin fibers 2. have many mitochondria Many myoglobin SLOW MUSCLES

6. Thicker fibers Fewer mitochondria Less myoglobin (“white meat) FAST MUSCLES

7. Glucose is not completely broken down and lactic acid is formed (a larger molecule) that makes muscles ache What happens if not enough oxygen is available?

8. Big Question for Chapter 6 • How do our cells obtain O2 for cellular respiration and dispose of CO2?

9. 6.1 Breathing • Isn’t that how we obtain oxygen? • Breathing = taking in oxygen in our lungs and removing carbon dioxide as we exhale

10. Respiration Really is... • Cellular respiration = breakdown of organic molecules (for energy) in the presence of oxygen (in mitochondrion)

11. 6.2 Cellular Respiration • C6H12O6 + 6O2 > 6CO2 + 6H2O + ATP

12. Glucose Bank • Break glucose bonds • Stored in ATP ATP glucose

13. Glucose contains Energy: • 1 gram glucose = 4 kcal of energy • What are kcal? Kilocalories • 1 kilocalorie = 1000 calories

14. 75% of energy of daily food just to maintain 2,200 kcal of energy per day needed for average adult 6.3 Need heat to stay alive

15. Walking at 3 mph, how far would you have to travel to “burn off” the equivalent of an extra slice of pizza, which has about 475 kcal? HINT: (p. 91) Walking 3 mph consumes per hour 158 kcal 475/158 = 3 hrs. 3 mph X 3 = 9mi Calculate

16. 6.4 Just how DO our cells extract energy from organic fuel molecules? • The glucose is dismantled and the energy stored in the bonds is carried by electrons.

17. We don’t see e-, but we see H atoms. • C6H12O6 + 6O2 > 6CO2 + 6H2O + ATP • (hydrogen atom = • one proton and one electron)

18. What drives this to happen? • OXYGEN • A strong tendency to pull electrons from other atoms

19. 6.5 Redox Reaction • Movement of electrons from one molecule to another is an oxidation-reduction reaction

20. Oxidation loss of electrons from one substance Loss of H Reduction addition of electrons to another substance Gain of H Redox reaction

21. "Leo goes Ger” • Loss of electrons = oxidation • Gain of electrons = reduction

22. Dehydrogenase Enzyme Remove H atoms NAD+ nicotinamide adenine dinucleotide coenzyme used to shuttle electrons Key Players of Redox Reactions

23. How NADH becomes a “Hydrogen Carrier” • NAD+ + 2H dehydrogenaseNADH2 • picks up 2 e- and • e-2H+ and 2e-

24. Electron Carrier • A.k.a. “hydrogen carrier” • Empty With e-/H e- NADH NAD+ NADH

25. p. 93 • C4H6O5 C4H2O5 • Oxidized • NAD+ NADH • Reduced

26. How do we get energy? • Big molecules in food break apart • Released electrons carried to NADH • Energy to ATP’s • You can now use ATP energy

27. 6.6 • Which has more energy? NAD+ NADH Why? NADH has picked up an e-

28. 6.6 ETC NADH brings e- • Electron Transport Chain • Pass e- from higher energy to lower energy state NAD+

29. So… • NAD+ can be recycled over and over

30. ETC • ETC Animation (click) • Note each carrier molecule has a greater affinity for e- than its uphill neighbor

31. Where is the ETC? • Inner membrane of the Mitochondrion

32. Sing the ETC Song • To the tune of “Buffalo Gals Won’t you Come Out Tonight”?

33. 6.7 Chemiosmosis • Movement of solutes across a membrane from where they are MORE concentrated to where they are LESS concentrated. • Movement of H+ ions (click here to see the proton H+ pumps)

34. “Down the Gradient” Note more H+ ions on one side of the membrane Went “against the gradient” and see energy was used to do this

35. Chemiosmosis • Diffusion of excess H+ ions across a membrane from high to low concentration • ADP + Pi = ATP

36. ATP Synthase • ATP Synthase Animation (click here to see the ATP synthase move H+ ions “against the gradient”) • ATP Synthase Animation (click here)

37. Makes ATP • Energy is generated from the movement of H+ ions …enough to cause a phosphate to join ADP to form ATP

38. Chemiosmosis and ETC working together on inner membrane • ETC and Chemiosmosis Together NADH and FADH2 carry protons (H+) and electrons (e-) to the electron transport chain

39. Mitochondrion: Site of Cellular Respiration • Mitochondrion Cellular Respiration (be sure to see the cool rotating ATP Synthase and the end of the program)

40. Peter Mitchell (1920 - 1992) • Developed the theory of chemiosmosis • Nobel Prize 1978

41. 2 Ways to Make ATP • Substrate-level phosphorylation • does not involve a membrane • makes only small amounts of ATP • Chemiosmosis • diffusion through a membrane of particles produces more ATP

42. 6.8 3 Stages of Cellular Respiration 1. Glycolysis 2. Krebs Cycle 3. ETC/Chemiosmosis

43. Glycolysis -Breaks down glucose into pyruvic acid -Occurs in cytoplasm -means “splitting of sugar”

44. Glycolysis • Start with 6-carbon glucose and breaks into two 3-carbon pyruvic acid molecules (or pyruvate)

45. Glycolysis actually has 9 steps…but you only need to learn that these molecules formed between glucose and pyruvic acid are called intermediates Glycolysis Animation

46. Needs 2 ATP to get started Makes 4 ATP Splits glucose into two pyruvates Makes NADH (an e- carrier) NET GAIN2 ATP’s Glycolysis: What do I need to know?

47. But... • Pyruvic acid itself does not enter the Krebs cycle

48. 6.10 “Grooming” Pyruvic Acid Haircut and Conditioning “HAIRCUT” As NADH is reduced to NAD+…pyruvic acid is oxidized (carbon atom removed as CO2) “CONDITIONING” Coenzyme A (from B vitamin) joins the 2-c fragmen MAKES-Acetyl Coenzyme A or CoA

49. 6.11 Ready to GO • The Acetyl-CoA is now ready to enter the Krebs cycle Hans Krebs (1900-1981) Yeah, he got a Nobel Prize, too

50. Krebs Cycle • Only 2-C of acetyl participates • (Coenzyme A is recycled) • Occurs in mitochondrial matrix