Electron Transport Chain and Oxidative Phosphorylation

• Oxidation of food molecules to produce energy (in the form of ATP). It consumes O2 and produces CO2.

  Cellular respiration
• Stages of cellular respiration

  1. Digestion of food polymers
  2. Production of Acetyl CoA
  3. Oxidation of Acetyl CoA to CO2 and H2O
• 4 pathways of respiration

  1. Glycolysis
  2. Krebs Cycle
  3. Electron Transport Chain
  4. ATP Synthesis
• This is the part of the cell where Electron Transport Chain occurs

  Mitochondria
• Protein complex of the ETC in Complex I

  NADH dehydrogenase
• Protein complex of ETC in Complex II

  Succinate CoQ oxidoreductase
• Protein complex of ETC in Complex III

  Cytochrome bc1 complex
• Protein complex of ETC in Complex IV

  Cytochrome C oxidase
• This is the only complex in ETC where no proton transfer occurs

  Complex II
• Higher concentration in the intermembrane space generates the proton motive force.

  True
• This is the enzyme responsible for ATP synthesis through the catalytic site in it

  ATP Synthase
• The subunit of ATP synthase where ATP synthesis occurs.

  F1
• The subunit of ATP Synthase also known as the proton-conduction unit.

  Fo
• A hypothesis proposed by Peter Mitchell in 1961 that talks about how electron transport and ATP synthesis are coupled by a proton gradient across the inner mitochondrial membrane.

  Chemiosmotic Hypothesis
• How many protons do complex I and IV pumps in ETC?

  4
• How many protons do complex III pumps in ETC?

  2
• Upon oxidation of NADH, how many protons are pumped?

  10
• Upon oxidation of FADH2 given that it just enters in complex II, how many protons are pumped?

  6
• How many protons does it require to produce a mole of ATP?

  4
• For each NADH, how much ATP is produced given that NADH yields 10 protons and each ATP mole needs 4 protons?

  2.5 ATP
• For each FADH2, how much ATP is produced given that FADH2 yields 6 protons and each ATP mole needs 4 protons?

  1.5 ATP
• The proton motive force drives the flow of protons back into the mitochondrial matrix through ATP synthase.

  True
• Inhibitor of ETC that is also an insect and fish poison.

  Rotenone
• Inhibitor of ETC that is also a barbiturate sedative.

  Amytal
• Inhibitor of ETC that is also an antibiotic.

  Piericidin
• Uncoupler of ETC and OP that was once used as a slimming agent.

  2, 4-Dinitrophenol
• Uncoupler of ETC and OP that is in the brown tissue mitochondrion.

  Thermogenin