Lectures ch06

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

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Lectures ch06

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

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