Energetics of glucose

[Bioguy]

Hi, I have a biochemistry question.

 

Throughout glycolysis and the Kreb's cycle, high energy electrons and protons (hydrogens) are removed and used to reduce coenzymes for ATP production in the electron transport chain.

 

The thing that is confusing is that even those hydrogens that are covalently bound to oxygen in hydroxyls seem to get extracted for energy production as well. How can a hydrogen that is already bound to an oxygen provide free energy by eventually being transferred to another oxygen?

 

I know that if you fully oxidize oleic acid (18 carbons, 36 hydrogens) you get approximately 144 ATPs, while if you fully oxidize 3 glucose molecules (also 18 carbons, 36 hydrogens) you only get, at best, about 108 ATPs. So, I see there is less energy in some of those hydrogens of glucose, but I don't see how those from the hydroxyls have any to give?

 

I hope that makes sense. Thank you.

[ajman2463]

From what i understand, the hydrogen that combines with the oxygen has no immediate purpose other than being a simple product. the energy that is used to make ATP are the H+'s that are moved across the membrane and into the intermembranal space. Those H+'s are moved into the Region where ATP synthase is, and that energy is used to produce ATP. The electron however, is sent to either a Fe-S protein or cytochrome ( i cant remember which one, it may be either/or)(and doesnt accept H+) and is used in the formation of H2O.

 

*remember, by the time the e- has reached the end of the transport chain, it doesnt have enough energy to move anymore hydrogen, so simple binds with hydrogen to the closest free radical, o2.

 

Hope that makes sense