Question

1) Compare the fate of Pyruvate in aerobic and anaerobic cell respiration

2) Explain how much ATP is produced in oxidative phosphorylation and where in the pathway it comes from    

Answer 1

1) cellular respiration is the process in which glucose is broken down to produce ATP.

• it involves glycolysis, pyruvate oxidation, Kreb's Cycle, and oxidative phosphorylation.

2) oxidative phosphorylation produce ATP from NADH and FADH2

• NADH produce 2.5 ATPs
• FADH2 produce 1.5 ATPs
• ATP production actually comes from the ATP synthase which is part of complex 5. (how many ATPs are being produced is determined by the flow of electrons in the electron transport chain along the increasing redox potential, which throw out protons from the mitochondrial matrix.)
• complex 1- throws out 4 H⁺
• complex 2- throws out no H⁺
• complex 3- throws out 4 H⁺
• complex 4- throws out 2 H⁺
• energy for throwing this protons out is generated by the flow of electrons in the ETC which is given by the NADH/ FADH2.
• these protons later enters the matrix through F1- F0 particle which has ATP synthase activity and thus ATP is produced.
• 4 H+ entry can produce 1 ATP.
• If energy is produced from NADH , complex 1,3,4 is involved. So it gives 2.5 ATP
• If energy is produced from FADH2 , complex 2,3,4 is involved. So it gives 1.5 ATP

NADH used here comes from Glycolysis and Kreb's Cycle .

FADH2 used here comes from Kreb's Cycle .