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Anaerobic and Aerobic Conditions

1. The energies of glycolysis shows that there is a large drop in free energy upon oxidation of glycerladehydes 3-phosphate to 1,3-bisphosphoglycerate. In the presence of oxygen, some of this energy is ultimately converted into ATP production. However, no such conversion happens under anaerobic conditions. Explain why?

2. How does the nonpolar nature of the active site in hexokinase promote phosphoryl transfer from ATP?

3. delta G knot for the aldolase reaction is 22.8 Kj/mol. In the cell at 37degree C, [DHAP]/[GAP]=5.5. Calculate the equilibrium ratio of [FBP]/[GAP] when [GAP]=10 to the power -4 M.

4. 2-phosphoglycerate and phosphoenolpyruvate differ only by dehydration between C-2 and C-3, yet the difference in delta G knot prime of hydrolysis is about -50Kj/mol. How does dehydration "trap" so much chemical energy?

Solution Preview

1. GAP ----> BPG is an oxidation reaction. NAD+ is reduced to NADH in the process. This is what is converted to 3 ATP later on during oxidative phosphorylation. However, in anaerobic respiration, oxidative phosphorylation cannot occur because there isn't any oxygen. The Krebs cycle backs up and glycolysis would come to an end too. However, in order to still make some ATP, many cells can operate some form of "anaerobic respiration." The end product of glycolysis, pyruvate, is reduced to lactate in humans (ethanol in yeasts). In order to do this, NADH gets reoxidized back to NAD+. This NAD+ can be used again ...

Solution Summary

This solution is provided in 454 words. It discusses oxidation and various reactions in detail.