Lectures ch06
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Lectures ch06

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This presentation is a brief overview of cellular respiration for basic concepts in biology.

This presentation is a brief overview of cellular respiration for basic concepts in biology.

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  • 1. Energy and Organisms
    • Organisms are classified based on the kind of energy they use.
      • Autotrophs
        • Use the energy from sunlight to make organic molecules (sugar)
        • Use the energy in the organic molecules to make ATP
      • Heterotrophs
        • Obtain organic molecules by eating the autotrophs
        • Use the energy in the organic molecules to make ATP
    • Autotrophs use photosynthesis.
      • To use the energy from light to make organic molecules
    • All organisms use cellular respiration.
      • To harvest the energy from organic molecules and use it to make ATP
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 6- Chapter 6
  • 2. Energy Transformation Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 6-
  • 3. Aerobic Respiration: An Overview
    • A series of enzyme controlled reactions
      • Oxygen is used to oxidize glucose.
      • Glucose is oxidized to form carbon dioxide.
      • Oxygen is reduced to form water.
    • During the oxidation of glucose
      • The C-H and O-H bonds will be broken.
      • The electrons will be transferred to electron carriers, NAD, and FAD.
        • Glycolysis and Kreb’s cycle
      • The electrons will be passed through an electron transport chain.
        • The energy from the electrons will be used to pump protons.
        • The energy from the diffusion of protons will be used to make ATP.
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 6-
  • 4. Aerobic Cellular Respiration: Overview 6- Glycolysis occurs in the cytoplasm of all cells.
  • 5. Glycolysis
    • The breakdown of glucose into pyruvic acid
    • Two ATP molecules are used to energize glucose.
    • As glucose is metabolized, enough energy is released to
      • Make 4 ATP molecules
        • 4 ATP made - 2 ATP used = net production of 2 ATP
      • Reduce 2 NAD + to make 2 NADH
    • Occurs in the cytoplasm
    • Anaerobic
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 6-
  • 6. Kreb’s Cycle
    • Also known as the citric acid cycle or the tricarboxylic acid (TCA) cycle
    • The breakdown of pyruvic acid
      • Released as carbon dioxide
    • Enough energy is released as one pyruvic acid molecule is metabolized to
      • Make 1 ATP
      • Reduce 4 NAD + to form 4 NADH
      • Reduce 1 FAD to form 1 FADH 2.
    • Occurs in the mitochondrial matrix
    6-
  • 7. Electron-Transport System
    • NADH and FADH 2 release the electrons they received during glycolysis and the Kreb’s cycle to the electron transport chain (ETC).
    • The proteins of the ETC transfer the electrons and use the energy released to pump protons.
      • Protons are pumped from the matrix to the intermembrane space.
      • Creates a concentration gradient
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 6-
  • 8. Electron-Transport System
    • Oxygen is the final electron acceptor at the end of the ETC.
      • Oxygen accepts the electrons, combines with protons, and becomes water.
    • The accumulated protons diffuse back into the matrix through ATP synthase.
        • The energy released from the diffusion fuels the formation of ATP.
    6-
  • 9. The Details of the Electron Transport System Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 6-
  • 10. Total Yields for Aerobic Cellular Respiration per Glucose Molecule
    • Glycolysis
      • 2 ATP
      • 2 NADH (converted to 2 FADH 2 )
    • Kreb’s cycle
      • 2 ATP
      • 8 NADH
      • 2 FADH 2
    • Electron transport chain
      • Each NADH fuels the formation of 3 ATP.
        • 8 NADH x 3 ATP = 24 ATP
      • Each FADH 2 fuels the formation of 2 ATP.
        • 4 FADH 2 x 2 ATP = 8 ATP
    • Total ATP = 2 + 2 + 24 + 8 = 36 ATP made from the metabolism of one glucose molecule.
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 6-
  • 11. Anaerobic Cellular Respiration
    • Some organisms do not have the enzymes for Kreb’s cycle or the electron transport system.
    • Some organisms can metabolize glucose in the absence of oxygen.
    • Metabolizing glucose in the absence of oxygen is called anaerobic respiration.
      • Involves the incomplete oxidation of glucose
      • Fermentation is an anaerobic pathway that uses an organic molecule as the final electron acceptor.
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 6-
  • 12. Anaerobic Cellular Respiration
    • Anaerobic respiration usually starts with glycolysis.
      • Glucose is metabolized into pyruvic acid.
      • 2 ATP are made.
    • The fermentation reactions oxidize NADH to regenerate the NAD + that is needed in glycolysis.
      • In the process, pyruvic acid is reduced to either lactic acid or ethanol or another organic molecule.
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 6-
  • 13. Alcoholic Fermentation
    • Starts with glycolysis
      • Glucose is metabolized to pyruvic acid.
      • A net of 2 ATP is made.
    • During alcoholic fermentation
      • Pyruvic acid is reduced to form ethanol.
      • Carbon dioxide is released.
    • Yeasts do this
      • Leavened bread
      • Sparkling wine
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 6-
  • 14. Lactic Acid Fermentation
    • Starts with glycolysis
      • Glucose is metabolized to pyruvic acid.
      • A net of 2 ATP is made.
    • During lactic acid fermentation
      • Pyruvic acid is reduced to form lactic acid.
      • No carbon dioxide is released.
    • Muscle cells have the enzymes to do this, but brain cells do not.
      • Muscle cells can survive brief periods of oxygen deprivation, but brain cells cannot.
      • Lactic acid “burns” in muscles.
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 6-
  • 15. The Bottom Line
    • Carbohydrates, fats, and proteins can all be used for energy.
      • Glycolysis and the Kreb’s cycle allow these types of molecules to be interchanged.
      • If more calories are consumed than used
      • The excess food will be stored as fat
      • Homeotherms – have a high metabolic rate and use this energy to maintain their body temperature.
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 6-
  • 16. What’s next?
    • Review your notes
      • Review this presentation if you feel you have missed something or need clarification
    • Review the animations located in the learning module to help you understand these processes.
    • Finally, use your book and notes to answer your HW questions; then submit them before the end of the day on Wednesday (6/22).
    Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 6-