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BEST ORGANELLE EVER…?

BEST ORGANELLE EVER…?. BEST ORGANELLE EVER…?. Ch 9. Cell Respiration. Cell Respiration = catabolic, makes ATP, exergonic (ΔG -686 kcal/mol) C 6 H 12 O 6 + 6 O 2 → 6 CO 2 + 6 H 2 O + energy ATP is made and used for energy, recycled, ATP ↔ ADP

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BEST ORGANELLE EVER…?

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  1. BEST ORGANELLE EVER…?

  2. BEST ORGANELLE EVER…?

  3. Ch 9 Cell Respiration

  4. Cell Respiration = catabolic, makes ATP, exergonic (ΔG -686 kcal/mol) • C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + energy • ATP is made and used for energy, recycled, ATP ↔ ADP • ADP + P = phosphorylation (common) • P-bond is very energetic

  5. Redox reaction = transfer of electrons from reactants to products, energy released • oxidation = loss of e-, reduction = gain of e-

  6. Figure 9.UN01 becomes oxidized(loses electron) becomes reduced(gains electron)

  7. Figure 9.UN03 becomes oxidized becomes reduced

  8. Overview Electrons are passed “downhill” from: glucoseNADH  electron transport chain  oxygen In a series of redox reactions Releases energy, therefore is exergonic

  9. The Key Players

  10. In resp., transfer of e- uses NAD+ and electron transport chain • NAD+ = an electron shuttle, is coenzyme and e- acceptor, converts to NADH, gains 2 e- and 1 p+, p165

  11. WHAT IS ROLE OF OXYGEN IN THESE EXAMPLES?

  12. Electron transport chain • Video • Made of e- carrier molecules in the mitochondrial membrane • electrons slowly get passed down to oxygen (final electron acceptor) and energy is given off, p165 • Why slow?

  13. OXIDATION • Oxygen is HIGHLY electronegative • (6 valence electrons) • Final electron acceptor in respiration • Ultimately results as water, also picking up H+ ions • Once a molecule has been oxidized, it has very little free energy

  14. Process of Cell Respiration in detail

  15. Phase 1) Glycolysis (what does the word mean?) • catabolic, glucose is broken into two 3-carbon parts, which are converted into two pyruvate molecules, easy, video • Where: cytosol • anaerobic • uses 2 ATP to start, 4 are released by substrate level phosphorylation: 2 ATP NET • 2 NAD+ converted (reduced) to 2 NADH • Exergonic: ΔG = -140 kcal/mol

  16. Substrate Level Phosphorylation, is about 10% of the ATP. • 90% occurs as result of oxidative phosphyrlation • occurs during glycolysis and the citric acid cycle P10

  17. Options → If O2 is available – pyruvate moves to a mitochondrion and the citric acid cycle (a.k.a. the Krebs cycle) to complete oxidation, if not then fermentation occurs (we’ll do later) In Mitochondria • Pyruvate is converted into acetyl CoA, (3-C into a 2-C molecule), makes it reactive, p170 • 2 NADH’s made (1 per pyruvate)

  18. During part 1 of phase 2 (pyruvate oxidation) pyruvate is oxidized and becomes acetyl coenzyme A, or acetyl CoA

  19. Phase 2) Krebs Cycle, p.170 • (citric acid, TCA cycle)– catabolic, in mitochondrial matrix • The CoAon acetyl CoA is removed and the acetyl group is added to oxaloacetate to create citrate • energy released, 8 step cycle • For every acetyl CoA (2 per glucose)  • 3 NADH, 1 FADH2, 2 CO2, 1 ATP made (SLP) • most energy is hidden in the electron carriers • ? GTP and GDP

  20. 3) Oxidative PhosphorylationElectron Transport Chain (ETC) • Where: inner mitochondria • Problem – we have many e- carriers • electronegativity increases down the chain so e- are pulled “downhill” towards oxygen, the final acceptor

  21. What is the ultimate purpose of the electron transport chain? Of the electrons?

  22. most carriers are metals or cytochromes • ATP production powered by [H+] gradient, p174 • ATP Synthase 

  23. Chemiosmosis • Flow of H+ (osmos = “pushing” H+) • = coupling of rxns to make ATP, p173, (diffusion & pumps) • e- move down ETC, H+ pumped out into intermembrane space creating a proton-motive force, H+ diffuse into matrix through ATP synthase to make ATP • process is enhanced by cristae (folds) in mitochondria

  24. 6/5/2014 28

  25. Process ATP by SLP CoEnzyme ATP by ETC Total Glycolysis Net 2 2 NADH 4-6 6-8 Oxidation of pyruvates - 2 NADH 6 6 krebs 2 6 NADH 2 FADH2 18 4 24 TOTAL = 36-38 - range 36-38 because of rounding p176-177

  26. Resp. is very efficient – 40% 7.3 kcal/mol ATP x 38 ATP/mol 686 kcal/mol glucose

  27. Fermentation • anaerobic, makes only 2 ATP, starts after glycolysis if no oxygen, 2 types • 1) alcoholic- 2 pyruvates broken down into 2 CO2 and ethanol, 2 NADH oxidized to 2 NAD+, replenishes NAD+ • many yeast, and bacteria, do

  28. 2) lactic acid – 2 pyruvates broken down into lactate • occurs in muscles when O2 is low

  29. Fermentation vs Respiration • both break down pyruvate and use NADH • in ferm. – final electron acceptor is pyruvate, in resp. it is O2 • more energy from respiration, 18 x more ATP • respiration needs O2

  30. some organisms are facultative anaerobes= they can switch back and forth from aerobic to anaerobic • What evolved first, aerobes or anaerobes? • other energy molecules (ex. fats) can be broken into parts to go into glycolysis, p180

  31. Regulation • Control of cell respiration is done by feedback inhibition – too much product inhibits rxn • control at certain enzymes in glycolysis and krebs • key control enzyme for citric acid cycle (in glycolysis) is phosphofructokinase • sensitive to ratios of ATP:ADP:AMP • citrate and ATP are allosteric inhibitors of pfk • ADP and AMP are allosteric activators of pfk

  32. Review with Bioflix on MasteringBiology.com

  33. How can sunlight, seen here as a spectrum of colors in a rainbow, power the synthesis of organic substances?

  34. Fun Fact: • Photosynthesis creates 160 billion metric tons of carbohydrates per year (or 17 stacks of our AP text reaching all the way to the sun)

  35. Ch 10 Photosynthesis Start with BioFlix on Masteringbiology.com

  36. Figure 10.2 (b) Multicellularalga (c) Unicellularprotists (e) Purple sulfurbacteria (a) Plants (d) Cyanobacteria 40 m 10 m 1 m

  37. Photosynthesis • = converts light energy trapped by chloroplasts into chemical energy stored as sugar • uses CO2 to as carbon source • Endergonic • Anabolic WAYS OF ENERGY AQUISITION • Autotroph = organism that makes its own food for energy • Photoautotroph= uses light, ex. algae • Chemoautotroph= uses chemicals, ex. bacteria • Heterotroph = organism that acquires (eats) its food for energy, ex. us

  38. Chloropast • where photosynthesis occurs • contains chlorophyll = green pigment, absorbs light • mostly in mesophyll of leaves • gas exchange through pores (stomata) • Anatomy of chloroplast: 1) intermembrane space- separates double membrane 2) thylakoid space- inside the thylakoid membrane - thylakoids (sacs in the chloroplast) and stacks called grana 3) Stroma = fluid-filled space outside the thylakoids, where sugar is made, only in eukaryotes

  39. Does CO2 or H2O get split to give oxygen? • Van Neil: gave bacteria H2S instead of water • the rxn gave sulfur as a byproduct, so… • splits H2O to give O2, later done with radioactivity • water is split and the electrons are transferred from water to carbon dioxide, reducing it to sugar • resp. was exergonic, photosynthesis is endergonic, energy required is light

  40. Photosynthesis Rxn 6 CO2 + 6 H2O + light energy → C6H12O6 + 6 O2

  41. Phase 1)Light Reactions (including the Electron Transport Chain) 1st stage in photosynthesis, convert light energy to chemical energy as ATP & NADPH, p188 Light = electromagnetic energy distance it travels = wavelength, ranges from 380 to 750 nm (visible spectrum) plants absorb blue and red light best, reflect green 6/5/2014 48

  42. 1)Light Reactions/Electron TransportChain What is water’s chief purpose?

  43. Pigments = substances that absorb light, • each has a specific wavelength it can absorb = absorption spectrum

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