Bio 104 5/29/96

• glycolysis: breakdown of glucose (6 carbon sugar)=> 2-3 carbon units called pyruvate
  Aerobic Organisms
• oxidation of pyruvate
• 2 stages
  1. oxidation of pyruvate to make Acetyl-CoA
  2. oxidation of Acetyl-CoA SEE FIGURE 7.9 The citric acid cycle. Figure 7.9
• decarboxylation is the production of CO₂ out of pyruvate
  • Acetyl group binds with the enzyme CoA
• Overall reaction: Pyruvate+NAD++CoA=>Acetyl-CoA+NADH+CO₂
  • Acetyl-CoA is used for:
    1. lipid synthesis
    2. oxidated further for production of ATP
  1. reaction catalyzed by enzyme called pyruvate dehydrogenase
     • multi enzyme complex: group of enzymes working together: an assembly line, eliminates intermediates
  2. Oxidation of Acetyl-CoA
     • part of the citric acid cycle Refer back to figure 7.9
     • enters cycle and CoA breaks off to form citrate
     • citrate undergoes reaction to form:
       1. CO₂
       2. electrons: eventually forming ATP
       3. regenerate 4 carbon to redo cycle
     • oxidation of NAD+ to NADH
     • net result is glucose is completely consumed SEE TABLE 7.1
  NAD and FAD are used to make ATP
  • electrons transfer to proteins in the inner membrane of the mitochondria SEE FIGURE 7.10 The electron transport chain. Figure 7.10

• NADH dehydrogenase complex
  • energy used to drive proton pump
  • water is produced
• ATP is made via the process of chemiosmosis
  1. protons pumped out of matrix
  2. driven by diffusion to cross back into the matrix
     • inner membrane not permeable to protons, but there are respiratory assemblies which serve as channels for protons into the matrix
  3. Part of the assembly is an enzyme complex ATP aynthetase SEE FIGURE 7.11 An overview of the energy extracted from the oxidation of glucose. Figure 7.11

1. Each activation of a proton pump= 1 ATP
2. Each NADH activates 3 pumps= 3 ATPs
3. Each FADH₂ activates 2 pumps= 2 ATPs
   • they enter at the 2nd pump

ATP 7.3 kcal/mol x 36= 263 kcal/mol/686
38% efficiency

• rest is lost by being converted into heat
• all controlled reactions
• process regulated by levels of ATP, feedback inhibition occurs when there is enough ATP

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