Chp' 6: Cellular Respiration: Harvesting Chemical Energy

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Chp. 6 Cellular Respiration Harvesting
Chemical Energy
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Energy Flow Chemical Cycling

• Energy can be traced back to where?
• Animals depend on plants photosynthesis

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Producers

• Autotrophs
• Make all their own organic matter
• Photosynthesis
• Most ecosystems depend entirely on

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Consumers

• Heterotrophs
• Cant photosynthesize
• Depend on producers

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Chemical Cycling

• Photosynthesis
• Cellular respiration
• Every living thing does it
• Producers make an excess of food
• Food for other living things

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Energy Flow Chemical Cycling
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Cellular Respiration

• Aerobic harvest of chemical energy from food
• Dont confuse it with respiration (breathing)!
• Three stages glycolysis, Krebs cycle, electron
  transport

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Breathing Cellular Respiration
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Overall Electron Traffic

• Downhill trip for electrons from glucose to
  oxygen
• Stepwise freeing of chemical energy
• Cells make ATP from ADP
• Oxygen works like gravity, pulling electrons
  down

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Role of Oxygen
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Cellular Respiration Roadmap
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Electron Transport Chain

• Each NADH ---gt up to 3 ATP
• Each FADH2 ---gt up to 2 ATP
• Gain of how many ATP from ETC?
• Overall net gain of how many ATP per glucose
  molecule?

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Adding It All Up
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Cellular Respiration Review
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Energy From Food!!!
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Fermentation In Muscle Cells

• Anaerobic without what?
• Think of sprinting
• Muscle cells have ATP to support anaerobic
  activity for 5 seconds
• Glycolysis does not require oxygen only
  generates 2 ATP per glucose
• Pyruvic acid converted to lactic acid
• Lactic acid builds up ---gt soreness

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Hitting the Wall!

• Critical lactic acid accumulation!!!
• Run out of fuel!!!

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Fermentation in Microorganisms

• Keep yeast cells in anaerobic
  environment
• Instead of lactic acid, what do they produce???