Would you consider TCA GTP generation to be SP or OP?

[laczlacylaci]

From my understanding,
SP: ADP+Pi->ATP (gly)
OP: ATP formation through multiple reactions of redox. (ETC)

I was taught that the TCA utilizes SP to generate GTP, but since there are redox rxns in the TCA (generation of NADH...) Would you consider this OP instead? (I think in the ETC and the TCA, the phosphate come from similar places?)

How do you really differentiate between the 2?

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[Domepiece]

This is an outline of the step which produces GTP in TCA, hopefully it helps you answer your question: a free-floating phosphate group opens a carbonyl in succinate-CoA, causing the CoA to leave. The phosphate group is plucked off by an enzyme (leaving succinate), which is then transferred to ADP/GDP.
https://en.wikipedia.org/wiki/Succinyl_coenzyme_A_synthetase#Chemical_Reaction_and_Enzyme_Mechanism

Not sure what SP is, so it is difficult to answer the second question.

 

[theonlytycrane]

Oxidative phosphorylation only occurs in the ETC where oxygen is the final electron acceptor in becoming H2O.

Succinyl-coa passes a phosphate group to a histidine residue that passes a phosphate group to GDP in forming GTP via substrate-level phosphorylation. As you mentioned, substrates in glycolysis also pass a phosphate group to ADP in a similar way.