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Cellular Respiration (Chapter 9)

Cellular Respiration (Chapter 9). Energy source. Autotrophs: Producers Plants, algae and some bacteria Make own organic molecules Heterotrophs: Consumers. Energy. All activities an organism performs requires energy. Cellular respiration. C 6 H 12 O 6 + 6 O 2

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Cellular Respiration (Chapter 9)

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  1. Cellular Respiration (Chapter 9)

  2. Energy source • Autotrophs: • Producers • Plants, algae and some bacteria • Make own organic molecules • Heterotrophs: • Consumers

  3. Energy • All activities an organism performs requires energy

  4. Cellular respiration C6H12O6 + 6 O2 ---> 6 CO2 + 6 H2O + ATP

  5. Cellular respiration

  6. Cellular Respiration • Catabolic • Enzymes break down substances • Harvest energy from C-H bonds • Or other chemical bonds Organic compounds + oxygen ⇨ Carbon Dioxide + water + energy

  7. Cellular respiration • Aerobic respiration • Chemical energy is harvested • Presence of oxygen • Anaerobic respiration • Process occurs without oxygen • Fermentation

  8. Anaerobic • Glucose to lactate (muscle cells) • Glucose to alcohol (yeast cells) • Does not yield as much energy

  9. Cellular Respiration • Exergonic • -686kcal/mole (-2,870kJ/mole) • Redox reaction • Glucose is oxidized, oxygen is reduced • Energy stored in glucose makes ATP • 38 ATP generated • ATP stores energy for use in cellular functions

  10. Redox reaction becomes oxidized becomes reduced

  11. Vocabulary NAD/NADH FAD ETC Phosphorylation Chemiosmosis ATP Synthase

  12. NAD & NADH • NAD: • Nicotinamide adenine dinucleotide • NAD+ oxidized form • NADH reduced form • NAD+ traps electrons from glucose • Function as energy carrier

  13. NAD & NADH • Dehydrogenase (enzyme) • Removes a pair of hydrogen atoms from glucose • Transfers one proton and 2 electrons to NAD+ H-C-OH + NAD+⇨ -C=O + NADH + H+ • Used to make ATP

  14. 2 e− + 2 H+ 2 e− + H+ NAD+ H+ NADH Dehydrogenase Reduction of NAD+ 2[H] (from food) H+ Oxidation of NADH Nicotinamide (reduced form) Nicotinamide (oxidized form)

  15. FAD • Flavin adenine dinucleotide • Transfers electrons

  16. Electron transport chain • Located inner membrane of mitochondria • Plasma membrane (prokaryotes) • Series of molecules (mostly proteins)

  17. Electron transport chain • Electrons fall to oxygen • In a series of energy releasing steps • High potential energy to low • Energy released generates ATP

  18. Electron transport chain 1/2 O2 + 2 H (from food via NADH) Controlled release of energy for synthesis of ATP 2 H+ + 2 e– ATP ATP Electron transport chain Free energy, G ATP 2 e– 1/2 O2 2 H+ H2O

  19. Phosphorylation • Addition of a phosphate group to a molecule • ATP is formed by a phosphorylation reaction • 1. Substrate-level phosphorylation • 2. Oxidative phosphorylation

  20. Substrate phosphorylation • Enzyme transfers a phosphate from a organic substrate molecule • ADP to make ATP • Direct formation • Glycolysis and Krebs cycle

  21. Oxidation phosphorylation • Energy from electron transport chain • Synthesis ATP • Adds an inorganic phosphate to ADP

  22. Chemiosmosis • Energy-coupling mechanism • Energy stored in hydrogen ion gradient across membrane • Makes ATP from ADP

  23. 2 ATP synthase H+ ADP + ATP P i H+ Chemiosmosis

  24. ATP Synthase • Enzyme helps make ATP • Located in membrane • Changes ADP to ATP • Uses energy from a proton gradient across membrane

  25. INTERMEMBRANE SPACE Stator H+ Rotor Internal rod Catalytic knob ADP + P i ATP MITOCHONDRIAL MATRIX

  26. The Reactions (Cell Respiration) • Glycolysis • Krebs cycle (citric acid cycle) • Electron transport chain (oxidative phosphorylation)

  27. Cellular respiration

  28. Glycolysis • Happens in cytoplasm • Starts with glucose • Yields: • 2 pyruvate (3 carbons) molecules • 4 ATP (net of 2 ATP) & 2 NADH • 10 enzyme catalyzed reactions to complete

  29. Glycolysis • Every living organism can carry out glycolysis • Occur in aerobic & anaerobic • Does not require oxygen • Oxygen present the Krebs cycle will begin

  30. Glycolysis • Part one (priming) • First 5 reactions are endergonic • 2 ATP molecules attach 2 phosphate groups to the glucose • Produces a 6 carbon molecule with 2 high energy phosphates attached

  31. Glycolysis • Part two (cleavage reactions) • 6 carbon molecule is split into 2 • 3-carbon molecules each with a phosphate (G3P)

  32. Glycolysis • Part three (energy harvesting reactions) • In two reactions 2- G3P molecules are changed to pyruvate • 4 ATP molecules are made (net of 2) • An energy rich hydrogen is harvested as NADH (2NADH)

  33. GLYCOLYSIS: Energy Investment Phase Glucose

  34. 1 GLYCOLYSIS: Energy Investment Phase Glucose 6-phosphate ATP Glucose ADP Hexokinase

  35. 1 2 GLYCOLYSIS: Energy Investment Phase Glucose 6-phosphate Fructose 6-phosphate ATP Glucose ADP Phosphogluco- isomerase Hexokinase

  36. 3 GLYCOLYSIS: Energy Investment Phase ATP Fructose 6-phosphate Fructose 1,6-bisphosphate ADP Phospho- fructokinase

  37. 3 4 5 GLYCOLYSIS: Energy Investment Phase Glyceraldehyde 3-phosphate (G3P) ATP Fructose 6-phosphate Fructose 1,6-bisphosphate ADP Isomerase Aldolase Phospho- fructokinase Dihydroxyacetone phosphate (DHAP)

  38. 3 5 2 4 1 GLYCOLYSIS: Energy Investment Phase Glyceraldehyde 3-phosphate (G3P) Fructose 6-phosphate Fructose 1,6-bisphosphate Glucose 6-phosphate ATP ATP Glucose ADP ADP Isomerase Aldolase Hexokinase Phospho- fructokinase Phosphogluco- isomerase Dihydroxyacetone phosphate (DHAP)

  39. 4 5 6 GLYCOLYSIS: Energy Payoff Phase 2 NADH Glyceraldehyde 3-phosphate (G3P) 2 2 NAD+ 2 H+ 2 Triose phosphate dehydrogenase 2 Isomerase 1,3-Bisphospho- glycerate Aldolase Dihydroxyacetone phosphate (DHAP)

  40. 4 6 5 7 GLYCOLYSIS: Energy Payoff Phase ATP 2 2 NADH Glyceraldehyde 3-phosphate (G3P) 2 ADP 2 2 NAD+ 2 H+ 2 2 Triose phosphate dehydrogenase Phospho- glycerokinase 2 Isomerase 1,3-Bisphospho- glycerate 3-Phospho- glycerate Aldolase Dihydroxyacetone phosphate (DHAP)

  41. 8 9 GLYCOLYSIS: Energy Payoff Phase H2O 2 2 2 2 Phospho- glyceromutase Enolase 2-Phospho- glycerate Phosphoenol- pyruvate (PEP) 3-Phospho- glycerate

  42. 8 9 10 Figure 9.9bb-3 GLYCOLYSIS: Energy Payoff Phase ATP 2 H2O 2 ADP 2 2 2 2 2 Phospho- glyceromutase Enolase Pyruvate kinase 2-Phospho- glycerate Phosphoenol- pyruvate (PEP) Pyruvate 3-Phospho- glycerate

  43. 6 9 8 7 10 GLYCOLYSIS: Energy Payoff Phase ATP 2 ATP 2 2 H2O 2 NADH 2 ADP ADP 2 2 H+ 2 NAD+ 2 2 2 2 + 2 Phospho- glycerokinase Phospho- glyceromutase Enolase Triose phosphate dehydrogenase Pyruvate kinase 2 Glycer- aldehyde 3-phosphate (G3P) 1,3-Bisphospho- glycerate 3-Phospho- glycerate 2-Phospho- glycerate Phosphoenol- pyruvate (PEP) Pyruvate

  44. Electron shuttles span membrane 2 NADH or 2 FADH2 2 NADH GLYCOLYSIS Glucose 2 Pyruvate + 2 ATP

  45. Glycolysis • Glucose converted to pyruvate. • First half uses 2 ATP • Forms 2 separate G3P (glyceraldehyde 3-phosphate)

  46. Glycolysis • Second half generates 4 ATP, 2 NADH & 2 pyruvate • Net results are 2 ATP, 2 NADH and 2 pyruvate • Takes place in the cytoplasm

  47. Oxidation of pyruvate • Pyruvate is changed into acetyl-CoA • First carboxyl group is removed • Leaves as carbon dioxide • 2 carbon molecule called acetate remains

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