Although O_2 does not participate directly in the reactions of the TCA cycle, the cycle operates only under aerobic conditions. Briefly explain this fact. How many ATP molecules are generated during the complete oxidative degradation of phosphoenolpyruvate (PEP) to CO_2 and H_2O? Assume the glycerol phosphate shuttle is operating and show how you arrived at your answer. Solution 2) even though oxygen does not participate in the TCA Cycle but the ATP and NADPH produced are passed in the ETC cycle where the oxygen acts as a electron transport.. Hence there the role of oxygen takes place which is not found in the case of anaerobic situations.. 3) when PEP gets converted to pyurvate I release 2 molecules of ATP.. But in this case only 1 ATP is produced as the one molecule of di-hydrooxyacetone phosphate converted to glyecerol-3- phosphate by glycerol cycle hence in the glycolysis step 1 molecule gets reduced hence 1 ATP gets reduced..!!.

1. Although O_2 does not participate directly in the reactions of the TCA cycle, the cycle operates
only under aerobic conditions. Briefly explain this fact. How many ATP molecules are
generated during the complete oxidative degradation of phosphoenolpyruvate (PEP) to CO_2
and H_2O? Assume the glycerol phosphate shuttle is operating and show how you arrived at
your answer.
Solution
2) even though oxygen does not participate in the TCA Cycle but the ATP and NADPH
produced are passed in the ETC cycle where the oxygen acts as a electron transport.. Hence there
the role of oxygen takes place which is not found in the case of anaerobic situations..
3) when PEP gets converted to pyurvate I release 2 molecules of ATP.. But in this case only 1
ATP is produced as the one molecule of di-hydrooxyacetone phosphate converted to glyecerol-3-
phosphate by glycerol cycle hence in the glycolysis step 1 molecule gets reduced hence 1 ATP
gets reduced..!!