I have some confusion about some steps in glycolysis where I can't account for the loss and addition of a hydrogen atom. Hopefully you can help.
The first is from the step between glyceraldehyde-3-phosphate to 1,3-bisphosphoglycerate (not sure how to type formulas here, so bear with me please, and P is the whole phosphate group)
with the payoff of NAD+ -> NADH +H+
Now I count 5 hydrogen atoms in glyceraldehyde-3-phosphate and if 2 of them are transfered to NADH +H+ through oxidization how come there are still 4 hydrogen atoms in 1,3-biphosphoglycerate?
My second issue is in the last step - phosphoenolpyruvate to pyruvate. This time a hydrogen atom is added, but I don't understand how that can happen while producing 2 ATP, where is all this energy coming from in this reaction? I read that PEP is very unstable, but guess I'd like some more information to understand better.
CH2 (double bonded carbon)
payoff 2 ADP -> 2 ATP