Cell Respiration Chapter 9

Slide 2 of 33 Why Respire?  Living cells require energy transfusions to perform most of their tasks  From external sources  Assembling polymers  (what is the general reaction called?)  Pumping substances across their gradient  (what is the generic reference for this process? Where did we see this in Lab 1?)  Moving

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Slide 4 of 33 Notes on Previous Slide  Energy flows into an ecosystem as sunlight  Leaves as heat  Why can’t energy just be created?  Which Law of Thermodynamics helps explain this flow?  Essential chemical elements of life are recycled  Photosynthesis (plants) make Oxygen and Sugars  Cellular respiration take oxygen and sugars, make CO 2 and H 2 O & energy  The products of respiration (CO 2 and H 2 O) are the raw materials of photosynthesis

Slide 5 of 33 Cellular Respiration  Cellular respiration is catabolic  Catabolic processes are exergonic  Energy release from glucose is used to phosphorylate ADP  ATP  So cellular respiration burns fuels and uses the energy to regenerate ATP  Life processes constantly consume ATP

Slide 6 of 33 Respiration Overall  Food  Glucose  NADH  ATP  Glycolysis  Pyruvate Oxidation  Kreb’s Cycle  Oxidative Phosphorylation  Cytoplasm  Mitochondrion  Matrix  Inner Mitochondrial Membrane

Slide 7 of 33 2 Respiration Pathways  Cell Respiration  Called Aerobic Respiration  Requires Oxygen  Generates 36 or 38 ATP per glucose  Fermentation  Called Anaerobic Respiration  Oxygen NOT needed  Ethanol or Lactic Acid forms  Generates 2 ATP per glucose

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Slide 10 of 33 3 Stages of Respiration Glycolysis  Decomposes glucose  6-Carbon to 2 (3-Carbon molecules)  Occurs in cytosol Citric Acid Cycle  Continues decomposing 2-Carbon into CO 2  Mitochondrial matrix Oxidative Phosphorylation  ETC + Chemiosmosis  Powered by redox rxns  Method of ATP synthesis  Across inner mitochondrial membrane

Slide 11 of 33 Cellular Respiration

Slide 12 of 33 Questions  Is respiration exergonic or endergonic? Why?  Is fermentation exergonic or endergonic? Why?  Does respiration require enzymes?  What are the 2 catabolic pathways?  How do they differ?

Slide 13 of 33 Questions (Page 2)  What are the 4 parts of cellular respiration?  Which of the parts produce ATP?  Which of the parts produce NADH?  Which part(s) of cellular respiration require oxygen?

Slide 14 of 33 Glycolysis  Splitting of glucose  Cytosol (cytoplasm)  6-Carbon molecule  2 (3-Carbon molecules)  2 Phases  Energy Investment (Consumes 2 ATP)  Energy Payoff (Produces 4 ATP)

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Slide 17 of 33 Pyruvate Oxidation  Pyruvate  Acetyl CoA  3-Carbon  2-Carbon  Needs to get into the mitochondrion  Transport protein  Produces  NADH or FADH 2  CO 2

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Slide 19 of 33 Citric Acid Cycle  Called Kreb’s Cycle OR TricarboxylicAcic Cycle (TCA)  Mitochondria  Produces  CO 2  NADH  FADH 2  ATP (Actually GTP  ATP)

Slide 20 of 33 Questions  What is Glycolysis?  What is produced in Glycolysis?  Where does Glycolysis occur in a eukaryotic cell?  Where does it occur in a prokaryotic cell?

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Slide 23 of 33 Oxidative Phosphorylation  2 Parts:  Electron Transport Chain  Chemiosmosis  Electron Transport Chain  Embedded in inner mitochondrial membrane  Pumps Protons out of the matrix into the intermembrane space  Establishes electrochemical gradient  Chemiosmosis  ATP Synthase makes ATP

Slide 24 of 33 A Different Perspective  Glycolysis & Citric Acid Cycle  Redox rxns  Decompose glucose into CO 2  Transfers electrons from Glucose to NAD + (NADH is formed)  Oxidative Phosphorylation  Accepts electrons from NADH and uses them to drive ATP synthesis  Series of steps  O2 is the final electron acceptor, forms H 2 O

Slide 25 of 33 Questions  What are the 4 Parts of Cellular Respiration?  What is the purpose of Pyruvate Oxidation?  What is produced in Pyruvate Oxidation?  For each glucose, how many pyruvate oxidations occur?

Slide 26 of 33 Questions (Page 2)  Where does the TCA cycle occur in a eukaryotic cell?  Where does it occur in a prokaryotic cell?  What are the 2 alternate names for the TCA cycle?

Slide 27 of 33 Questions (Page 3)  For each glucose, how many turns of the TCA cycle occur?  Each turn of the TCA cycle produces how much:  CO 2 ?  ATP?  NADH?  FADH 2 ?

Slide 28 of 33 Fermentation  2 Forms  Lactic Acid fermentation (2 ATP)  Alcoholic fermentation (2 ATP + 2 CO 2 )  Glycolysis + 1 extra step (Recycles NAD + )  Does NOT require oxygen

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Slide 32 of 33 Fermentation  Lactic Acid Fermentation  3-Carbon  3-Carbon  3-carbon = Lactate or Lactic acid (What functional group?)  Muscles  Alcoholic Fermentation  3-Carbon  2-Carbon  2-Carbon = Ethanol (What functional group?)  CO 2  Beer or wine

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