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Cell Respiration

Cell Respiration. Chapter 9. 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

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Cell Respiration

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  1. Cell Respiration Chapter 9

  2. 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

  3. 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 CO2 and H2O & energy • The products of respiration (CO2 and H2O) are the raw materials of photosynthesis

  4. 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

  5. Respiration Overall • Food  Glucose  NADH  ATP • Glycolysis  Pyruvate Oxidation  Kreb’s Cycle  Oxidative Phosphorylation • Cytoplasm  Mitochondrion  Matrix  Inner Mitochondrial Membrane

  6. 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

  7. 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 CO2 • Mitochondrial matrix • Oxidative Phosphorylation • ETC + Chemiosmosis • Powered by redoxrxns • Method of ATP synthesis • Across inner mitochondrial membrane

  8. Cellular Respiration

  9. 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?

  10. 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?

  11. 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)

  12. Pyruvate Oxidation • Pyruvate  Acetyl CoA • 3-Carbon  2-Carbon • Needs to get into the mitochondrion • Transport protein • Produces • NADH or FADH2 • CO2

  13. Citric Acid Cycle • Called Kreb’s Cycle OR TricarboxylicAcic Cycle (TCA) • Mitochondria • Produces • CO2 • NADH • FADH2 • ATP (Actually GTP  ATP)

  14. 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?

  15. 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

  16. A Different Perspective • Glycolysis & Citric Acid Cycle • Redoxrxns • Decompose glucose into CO2 • 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 H2O

  17. 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?

  18. 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?

  19. Questions (Page 3) • For each glucose, how many turns of the TCA cycle occur? • Each turn of the TCA cycle produces how much: • CO2? • ATP? • NADH? • FADH2?

  20. Fermentation • 2 Forms • Lactic Acid fermentation (2 ATP) • Alcoholic fermentation (2 ATP + 2 CO2) • Glycolysis + 1 extra step (Recycles NAD+) • Does NOT require oxygen

  21. 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?) • CO2 • Beer or wine

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