Glycolysis Energy Yield and Regulation

Compare the ATP yield from glycolysis under aerobic vs. anaerobic conditions. (a) Calculate the net ATP yield per glucose under aerobic conditions (assuming malate-aspartate shuttle). (b) Calculate the net ATP yield per glucose under anaerobic conditions (lactic acid fermentation). (c) Explain why phosphofructokinase-1 (PFK-1) is considered the committed step rather than hexokinase. (d) How do ATP, AMP, citrate, and fructose-2,6-bisphosphate regulate PFK-1? (e) From a thermodynamic perspective, why is the PFK-1 reaction essentially irreversible in vivo?