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Releasing Chemical Energy (Ch. 8)

Respiration Rap……. Releasing Chemical Energy (Ch. 8). Giant panda snacking on bamboo. Aerobic Respiration Steps. 1) Glycolysis 2) Krebs Cycle 3) E.T.C. Step 1: Glycolysis. In cytoplasm (cytosol: not organelle) Start: glucose (6 C sugar), electron-empty NAD (NAD+), ADP, phosphate

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Releasing Chemical Energy (Ch. 8)

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  1. Respiration Rap…… Releasing Chemical Energy (Ch. 8) • Giant panda snacking on bamboo

  2. Aerobic Respiration Steps • 1) Glycolysis 2) Krebs Cycle 3) E.T.C.

  3. Step 1: Glycolysis • In cytoplasm (cytosol: not organelle) • Start: glucose (6 C sugar), electron-empty NAD (NAD+), ADP, phosphate • End: 2 ATP, two 3-C molecules (pyruvic acid), two NADH.

  4. Where are we now? • Glycolysis done, now Krebs Cycle.

  5. O O Step 2: Krebs Cycle • Part 1: grooming pyruvic acid (3-C) • Start: pyruvic acid, Coenzyme A (CoA), NAD+ • End: Acetyl-CoA CO2 NADH pyruvate coenzyme A (CoA) NAD+ carbon dioxide NADH CoA acetyl-CoA

  6. =CoA acetyl-CoA CoA oxaloacetate citrate H2O NADH ATP NAD+ H2O O O O O isocitrate malate NAD+ H2O NADH fumarate FADH2 a-ketoglutarate FAD NAD+ CoA NADH succinate succinyl-CoA ADP + phosphate group Step 2: Krebs Cycle • Part 2: Actual Krebs Cycle • 2-C piece added to 4-C piece to start

  7. =CoA acetyl-CoA CoA oxaloacetate citrate H2O NADH ATP NAD+ H2O O O O O isocitrate malate NAD+ H2O NADH fumarate FADH2 a-ketoglutarate FAD NAD+ CoA NADH succinate succinyl-CoA ADP + phosphate group Step 2: Krebs Cycle • Same 4-C piece comes out at end • 2 CO2 represent the 2 Cs put in by Acetyl CoA.

  8. =CoA acetyl-CoA CoA oxaloacetate citrate H2O NADH ATP NAD+ H2O O O O O isocitrate malate NAD+ H2O NADH fumarate FADH2 a-ketoglutarate FAD NAD+ CoA NADH succinate succinyl-CoA ADP + phosphate group Step 2: Krebs Cycle • Part 2: 1 ATP made by direct phosphorylation • 3 NADH made.

  9. =CoA acetyl-CoA CoA oxaloacetate citrate H2O NADH ATP NAD+ H2O O O O O isocitrate malate NAD+ H2O NADH fumarate FADH2 a-ketoglutarate FAD NAD+ CoA NADH succinate succinyl-CoA ADP + phosphate group Step 2: Krebs Cycle • FAD shows up!(electron carrier) • Reduced: FADH2 • Holds high energy electrons from C.

  10. Step 2: Krebs Cycle • Summary: • Pyruvic acid enters: all 3 C oxidized to CO2 • Some ATP made (direct phosphorylation) • Lots high energy electron carriers made (NADH, FADH2).

  11. Where are we now? • Glycolysis and Krebs Cycle done, now: E.T.C. • Why? • Most glucose energy in reduced electron carriers (NADH & FADH2) • How make into ATP? E.T.C.

  12. Last Step: E.T.C. • Flashback!

  13. Last Step: E.T.C. • In mitochondrion. Inner & outer membranes

  14. Last Step: E.T.C. • 1) Electrons from electron carriers donated to E.T.C. • Electron carriers oxidized: NAD+ & FAD

  15. Last Step: E.T.C. • 2) Electrons move: lose energy, H+ crosses membrane

  16. Last Step: E.T.C. • 3) O accepts low energy electrons & H+ to make water • 4) ATP synthase: H+ cross membrane, release energy, ATP made

  17. Last Step: E.T.C. • The E.T.C. show……. Click here for the movie! The Song….. “Let’s start the show…..” Warning: contains graphic images of high energy electrons and overt scenes of oxidation and reduction. Parental discretion advised.

  18. Where are we now?

  19. What my students hear when I lecture.... A word about...Studying! Blah, blah, blah..... • Respiration Rap……

  20. Finishing Ch. 8 • Aerobic respiration done! • C in glucose oxidized • Low energy C (C-O bonds) • Some energy transferred ATP.

  21. Summary Equation for Aerobic Respiration C6H12O6 + 6O2 6CO2 + 6H2O glucose oxygen water carbon dioxide Finishing Ch. 8 • Flashback: Equation aerobic respiration.

  22. Finishing Ch. 8: Quick Summary • Glycolysis: glucose into 2 pyruvic acid, makes 2 ATP and 2 NADH • Krebs cycle: pyruvic acid C oxidized to CO2. Some ATP made: most energy in NADH and FADH2 • E.T.C.: NADH & FADH2 energy to ATP. O2 empties chain: combines electrons & H+ to form water.

  23. ATP accounting: how much? Glycolysis: 2 Krebs cycle: 2 E.T.C.: 32 About 36!

  24. Summary Equation for Aerobic Respiration C6H12O6 + 6O2 6CO2 + 6H2O glucose oxygen water carbon dioxide Focus on water • Water made (“metabolic water”) • Kangaroo rat!

  25. Making ATP when no O2 • Fermentation: Glycolysis plus 1 step • Step makes electron-empty NAD+ again • Not efficient: only 2 ATP per glucose!. • Alcoholic fermentation: yeast cells (fungi).

  26. Making ATP when there’s no O2 • Alcoholic fermentation (yeast cells: fungi). • Start: glucose, NAD+, ADP, phosphate • End: CO2 + ethanol (2C), NAD+, 2 ATP No O No mitochondrion

  27. Alcoholic fermentation summary • Rest energy? In ethanol C-H bonds (burns!)

  28. Making ATP when there’s no O2 • Human cells can do fermentation • Ex: muscles when O runs low • Alcoholic fermentation?

  29. Making ATP when there’s no O2 • Lactic acid fermentation: Glycolysis + extra step • Start: glucose, NAD+, ADP, phosphate • End: lactic acid (3C), NAD+, 2 ATP No O No mitochondrion

  30. Making ATP processes: summary • Aerobic respiration: glycolysis, Krebs cycle, ETC. Yields 36 ATP: needs O2!

  31. Making ATP processes: summary • Fermentation: glycolysis plus 1 step (alcoholic or lactic acid fermentation). Yields 2 ATP: works w/o O

  32. Making ATP from molecules other than glucose • Proteins, fats have energy (C-H bonds) • Your cells can convert those into ATP • How? • Link chemical pathways by common intermediates.

  33. 2 pathways:(letters stand for particular molecules) Pathway 1: A G I Q Pathway 2: X B G R G in both pathways: common intermediate

  34. Common intermediates can link pathways Cell can make R or Q, starting from A or X. Pathway 1: A X B R Pathway 2: G I Q

  35. Making ATP from molecules other than glucose • Common intermediates fed into aerobic respiration • Reverse: common intermediates build proteins, fats, or carbohydrates.

  36. How energy into C molecules? • Respiration generates ATP • Photosynthesis: puts energy into molecules • Converts light energy to chemical energy.

  37. Photosynthesis (Ch. 7) Anabaena (lab 3) • Photosynthetic organisms: producers or autotrophs • Put energy into life! Plants, algae, photosynthetic bacteria

  38. Photosynthesis (Ch. 7) • (Mostly) reverse aerobic respiration • Endergonic reaction • Oxidation & reduction: C reduced (H replaces O).

  39. Low energy wavelength High energy wavelength Setting stage: light & pigments • Photosynthesis captures light energy • What’s light? Electromagnetic radiation • Particle & wave (wavelength: distance peak to peak) • Long wave: little energy (vice versa)

  40. Setting the stage • Single unit light called “photon”.

  41. Wavelength of light (nanometers) Setting the stage: light and pigments • Visible light wavelengths: nanometers (nano: one billionth or 10-9 meters!).

  42. Setting the stage: light and pigments • Pigment: molecule absorbs light energy • “Absorb:” capture energy photon into electron energy

  43. Setting the stage: light and pigments • Plant pigments: • Chlorophyll (2 forms: “a” & “b”) • Accessory pigments (carotene & xanthophyll). chlorophyll a

  44. Setting the stage: light and pigments • Plant pigments: • Chlorophyll (2 forms: “a” & “b”) • Accessory pigments (carotene & xanthophyll). beta-carotene

  45. Setting the stage: light & pigments • Absorption of colors varies

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