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Chapter 6

Chapter 6. 0. How Cells Harvest Chemical Energy. 1/26/11 – “C” Day . Objective: To understand how eukaryotic cells harvest energy Do Now: What is the overall chemical equation for Cellular Respiration? Where does this occur in eukaryotic cells?. Today: Complete Calorimetry Lab

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Chapter 6

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  1. Chapter 6 0 How Cells Harvest Chemical Energy

  2. 1/26/11 – “C” Day • Objective: To understand how eukaryotic cells harvest energy • Do Now:What is the overall chemical equation for Cellular Respiration? Where does this occur in eukaryotic cells? • Today: • Complete Calorimetry Lab • Complete Data Table, Answer Post-Lab Analysis 12 - 14, Do Further Investigation in blank space provided (under data table)

  3. 1/28/11 – “D” Day • Objective: To understand how eukaryotic cells harvest energy • Do Now:What types of food do you predict have the most energy? Extra Credit – Bring in a Nutrition Facts label tomorrow! • Today: • Complete Calorimetry Lab • Complete Data Table, Answer Post-Lab Analysis 12 & 14, Do Further Investigation in blank space provided (under data table)

  4. 1/31/11 – “E” Day • Objective: To understand how eukaryotic cells harvest energy • Do Now:What types of food have the most energy? Did you bring in a Nutrition Label? • Today: • Check/Discuss/Complete Calorimetry Lab • Continue Chapter 6 Notes • HW – Read through 6.14 and complete up to Exercise 8 for TOMORROW!

  5. 1/31/11 – “E” Day • Objective: To understand how eukaryotic cells harvest energy • Do Now:What is the role of NADH and FADH2 in the process of cellular respiration? Where are they created? • Today: • Check in HW • Continue Notes!

  6. 2/1/11 – “F” Day • Objective: To understand how eukaryotic cells harvest energy • Do Now:What are the products of glycolysis? Where do they go?

  7. 2/2/11 – “A” Day • Objective: To understand how eukaryotic cells harvest energy • Do Now:What steps follow glycolysis in cell respiration? What are the products?

  8. 2/14/11 – “C” Day • Objective: To understand how exercise influences cellular respiration in humans • Do Now:How will you measure CO2 production for your experiment? Why is a reference tube necessary?

  9. 0 • How Is a Marathoner Different from a Sprinter? • Human muscles contain two different types of muscle fibers • That perform differently under different conditions

  10. 0 • The different types of muscle fibers • Function either aerobically, with oxygen, or anaerobically, without oxygen • Cellular respiration • Is the process by which cells produce energy aerobically

  11. INTRODUCTION TO CELLULAR RESPIRATION 0 • Photosynthesis and cellular respiration provide energy for life • Cellular respiration makes ATP and consumes O2 • During the oxidation of glucose to CO2 and H2O

  12. Sunlight energy ECOSYSTEM Photosynthesis in chloroplasts Glucose CO2 + + H2O O2 Cellular respiration in mitochondria ATP (for cellular work) Heat energy 0 • Photosynthesis uses solar energy • To produce glucose and O2 from CO2 and H2O Figure 6.1

  13. O2 Breathing CO2 Lungs O2 CO2 Bloodstream Muscle cells carrying out Cellular Respiration Glucose + O2 CO2 +H2O +ATP 0 • 6.1 Breathing supplies oxygen to our cells and removes carbon dioxide • Breathing provides for the exchange of O2 and CO2 • Between an organism and its environment Figure 6.2

  14. 2/3/11 – “A” Day • Objective: To understand how eukaryotic cells harvest energy • Do Now:What steps follow glycolysis in cell respiration? What are the products?

  15. O2 CO2 C6H12O6 6 6 H2O ATPs + + 6 + Carbon dioxide Glucose Energy Oxygen gas Water 0 • 6.2 Cellular respiration banks energy in ATP molecules • Cellular respiration breaks down glucose molecules • And banks their energy in ATP Figure 6.3

  16. CONNECTION 0 • 6.3 The human body uses energy from ATP for all its activities • ATP powers almost all cellular and body activities Table 6.4

  17. BASIC MECHANISMS OF ENERGY RELEASE 0 • 6.4 Cells tap energy from electrons transferred from organic fuels to oxygen • Electrons lose potential energy • During their transfer from organic compounds to oxygen

  18. Loss of hydrogen atoms (oxidation) C6H12O6 6 CO2 Energy 6 O2 + 6 H2O + + Glucose (ATP) Gain of hydrogen atoms (reduction) 0 • When glucose is converted to carbon dioxide • It loses hydrogen atoms, which are added to oxygen, producing water Figure 6.5A

  19. 0 • 6.5 Hydrogen carriers such as NAD+ shuttle electrons in redox reactions • In an oxidation-reduction (redox) reaction • the loss of electrons is called oxidation (LEO) • the gain of electrons is called reduction (GER)

  20. Oxidation H + O 2H H O Dehydrogenase Reduction H+ NAD+ NADH + 2H + (carries 2 electrons) 2H+ 2e + 0 • Dehydrogenase removes electrons (in H atoms) from fuel molecules (oxidation) • And transfers them to NAD+ (nictotinamide adenine dinucleotide) (reduction) Figure 6.5B

  21. NADH ATP NAD+ + 2e Controlled release of energy for synthesis of ATP H+ Electron transport chain 2e 1 O2 2 H+ 2 H2O 0 • NADH passes electrons • To an electron transport chain • As electrons “fall” from carrier to carrier and finally to O2 • Energy is released in small quantities 6.6 Redox reactions release energy when electrons “fall” from a hydrogen carrier to oxygen Figure 6.5C

  22. 0 • NADH delivers its electrons to an electron carrier (blue balls in diagram below) • Releasing energy with each transfer • These reactions in series are called • Electron Transport Chains  these reactions release H20 as a waste product

  23. 0 6.7 Two mechanisms generate ATP • In chemiosmosis • cells use the energy in concentration gradients to generate ATP using protein complexes called ATP Synthases

  24. Enzyme P Adenosine P P ATP ADP P Organic molecule(substrate) P 0 • In substrate-level phosphorylation • an enzyme transfers a phosphate molecule to ADP (Adenosine Diphosphate) Figure 6.7B

  25. STAGES OF CELLULAR RESPIRATION AND FERMENTATION 0 • 6.8 Overview: Cellular respiration occurs in three main stages • Cellular respiration • Occurs in three main stages

  26. 0 • Stage 1: Glycolysis • Occurs in the cytoplasm • Breaks down glucose into pyruvate, producing a small amount of ATP

  27. 0 • Stage 2: The citric acid cycle (Kreb’s Cycle) • Takes place in the mitochondria • Completes the breakdown of glucose, producing a small amount of ATP • Supplies the third stage of cellular respiration with electrons

  28. 0 • Stage 3: Oxidative phosphorylation • Occurs in the mitochondria • Uses the energy released by “falling” electrons to pump H+ across a membrane • Harnesses the energy of the H+ gradient through chemiosmosis, producing ATP

  29. NADH High-energy electrons carried by NADH NADH FADH2 and OXIDATIVE PHOSPHORYLATION(Electron Transport and Chemiosmosis) GLYCOLYSIS CITRIC ACID CYCLE Glucose Pyruvate Mitochondrion Cytoplasm ATP CO2 CO2 ATP ATP Substrate-level phosphorylation Substrate-level phosphorylation Oxidative phosphorylation 0 • An overview of cellular respiration Figure 6.6

  30. H+ 2 + 2 NAD+ 2 NADH Glucose 2 Pyruvate + 2 2 P ATP 2 ADP 0 • 6.9 Glycolysis harvests chemical energy by oxidizing glucose to pyruvate • In glycolysis, ATP is used to prime a glucose molecule • Which is split into two molecules of pyruvate Figure 6.7A

  31. Enzyme P Adenosine P P ATP ADP P Organic molecule(substrate) P 0 • Glycolysis produces ATP by substrate-level phosphorylation • In which a phosphate group is transferred from an organic molecule to ADP Figure 6.7B

  32. 4 3 1 • In the first phase of glycolysis • ATP is used to energize a glucose molecule, which is then split in two PREPARATORY PHASE(energy investment)  Steps      –   A fuel molecule is energized, using ATP. Glucose ATP Step 1 ADP Glucose-6-phosphate P 2 P Fructose-6-phosphate ATP 3 ADP P Fructose-1,6-diphosphate P  Step      A six-carbon intermediate splits into two three-carbon intermediates. 4 Figure 6.7C

  33. 5 5 6 6 7 7 8 8 9 9 • In the second phase of glycolysis • ATP, NADH, and pyruvate are formed P P Glyceraldehyde-3-phosphate(G3P)  Step     A redox reaction generates NADH. 5 6 9 ENERGY PAYOFF PHASE NAD  NAD  P 6 6 P NADH NADH +H +H P P P P 1,3-Diphosphoglycerate  Steps     –      ATP and pyruvate are produced. 9 6 ADP ADP 7 7 ATP ATP P 3-Phosphoglycerate P P P 8 8 2-Phosphoglycerate H2O H2O P P Phosphoenolpyruvate(PEP) 9 9 ADP ADP ATP ATP Pyruvate Figure 6.7C

  34. + H+ NADH NAD+ CoA Pyruvate Acetyl CoA(acetyl coenzyme A) CO2 Coenzyme A Figure 6.8 • 6.10 Pyruvate is chemically groomed for the citric acid cycle • Prior to the citric acid cycle • Enzymes process pyruvate, releasing CO2 and producing NADH and acetyl CoA 2 1 3

  35. Acetyl CoA CoA CoA CO2 2 CITRIC ACID CYCLE NAD+ 3 FADH2 3 FAD NADH + 3 H+ ADP + ATP P 0 • 6.9 The citric acid cycle completes the oxidation of organic fuel, generating many NADH and FADH2 molecules • In the citric acid cycle • The two-carbon acetyl part of acetyl CoA is oxidized Figure 6.9A

  36. 0 • The two carbons are added to a four-carbon compound, forming citrate • Which is then degraded back to the starting compound

  37. CoA Acetyl CoA CoA 2 carbons enter cycle Oxaloacetate 1 Citrate + H+ NADH 5 CO2 leaves cycle NAD+ 2 CITRIC ACID CYCLE NAD+ +H+ Malate NADH + P ADP FADH2 4 ATP Alpha-ketoglutarate FAD 3 CO2 leaves cycle Succinate + H+ NAD+ NADH Step 2 4 Steps 1 3 Steps and 5 and Acetyl CoA stokes the furnace. NADH, ATP, and CO2 are generated during redox reactions. Redox reactions generate FADH2 and NADH. Figure 6.9B • For each turn of the cycle • Two CO2 molecules are released • The energy yield is one ATP, three NADH, and one FADH2

  38. CoA Acetyl CoA CoA 2 carbons enter cycle Oxaloacetate 1 Citrate + H+ NADH 5 CO2 leaves cycle NAD+ 2 CITRIC ACID CYCLE NAD+ +H+ Malate NADH + P ADP FADH2 4 ATP Alpha-ketoglutarate FAD 3 CO2 leaves cycle Succinate + H+ NAD+ NADH Step 2 4 Steps 1 3 Steps and 5 and Acetyl CoA stokes the furnace. NADH, ATP, and CO2 are generated during redox reactions. Redox reactions generate FADH2 and NADH. Figure 6.9B

  39. 2/2/11 – “A” Day • Objective: To understand how eukaryotic cells harvest energy • Do Now:What steps follow glycolysis in cell respiration? What are the products?

  40. 2/8/11 – “E” Day • Objective: To understand how eukaryotic cells harvest energy • Do Now:How do cells obtain energy in the absence of oxygen?

  41. 2/9/11 – “F” Day • Objective: To understand how eukaryotic cells harvest energy • Do Now:What are the two types of cellular respiration? Explain each. • Today: • Discuss/Hand-in Mitochondrial Disease Article • Cellular Respiration Lab – Design Diagram – 2 DV’s • HW - Complete Yeast Lab • Announcements: • PJAS Competition • Science Movie Night - 2/14 in D22!

  42. 2/10/11 – “A” Day • Objective: To understand how eukaryotic cells harvest energy • Do Now:What are the two types of anaerobic cellular respiration? Describe each. • Today: • Turn in Yeast Lab! • Review Activity • Announcements: • PJAS Competition • Science Movie Night - 2/14 in D22!

  43. 2/11/11 – “B” Day • Objective: To understand how eukaryotic cells harvest energy • Do Now:Put Everything Away – Get started on your test! • Today: • Test • Announcements: • PJAS Competition • Science Movie Night - 2/14 in Audion!

  44. 0 • 6.10 Most ATP production occurs by oxidative phosphorylation • Electrons from NADH and FADH2 • Travel down the electron transport chain to oxygen, which picks up H+ to form water • Energy released by the redox reactions • Is used to pump H+ into the space between the mitochondrial membranes

  45. . H+ H+ H+ H+ H+ Protein complex H+ H+ ATP synthase H+ Electron carrier H+ Intermembrane space Inner mitochondrial membrane FADH2 FAD Electron flow 1 +2 O2 H+ NAD+ NADH 2 H+ H+ Mitochondrial matrix + P ATP ADP H+ H2O H+ Chemiosmosis Electron Transport Chain OXIDATIVE PHOSPHORYLATION Figure 6.10 0 • In chemiosmosis, the H+ diffuses back through the inner membrane through ATP synthase complexes • Driving the synthesis of ATP

  46. Cyanide, carbon monoxide Rotenone Oligomycin H+ H+ H+ ATPSynthase H+ H+ H+ H+ H+ H+ DNP FAD FADH2 1 + O2 2 H+ NADH NAD+ 2 H+ + ATP P ADP H+ H2O H+ Electron Transport Chain Chemiosmosis CONNECTION 0 • 6.11 Certain poisons interrupt critical events in cellular respiration • Various poisons • Block the movement of electrons • Block the flow of H+ through ATP synthase • Allow H+ to leak through the membrane Figure 6.11

  47. 0 • 6.12 Review: Each molecule of glucose yields many molecules of ATP • Oxidative phosphorylation, using electron transport and chemiosmosis • Produces up to 38 ATP molecules for each glucose molecule that enters cellular respiration Electron shuttleacross membrane Mitochondrion 2 2 NADH NADH Cytoplasm (or 2 FADH2) 2 2 6 FADH2 NADH NADH OXIDATIVE PHOSPHORYLATION (Electron Transport and Chemiosmosis) GLYCOLYSIS 2 AcetylCoA 2 CITRIC ACIDCYCLE Glucose Pyruvate + about 34 ATP + 2 ATP + 2 ATP by substrate-level phosphorylation by oxidative phosphorylation by substrate-level phosphorylation About38 ATP Maximum per glucose: Figure 6.12

  48. 0 • 6.13 Fermentation is an anaerobic alternative to cellular respiration • Under anaerobic conditions, many kinds of cells • Can use glycolysis alone to produce small amounts of ATP

  49. 2 2 NADH 2 2 NAD+ NADH NAD+ GLYCOLYSIS P 2 ADP + 2 ATP 2 2 Pyruvate 2 Lactate Glucose 0 • In lactic acid fermentation • NADH is oxidized to NAD+ as pyruvate is reduced to lactate Figure 6.13A

  50. NADH NAD+ 2 NAD+ NADH 2 2 2 GLYCOLYSIS 2 ADP + 2 CO2 released 2 P 2 ATP 2 Ethanol Glucose 2 Pyruvate Figure 6.13B 0 • In alcohol fermentation • NADH is oxidized to NAD+ while converting pyruvate to CO2 and ethanol Figure 6.13C

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