Biology Forums - Study Force

In stages 1, 2, and 3 of cellular respiration (glycolysis, pyruvate oxidation and the kreb's cycle), every time that two hydrogen atoms are removed form a intermediate (eg. when malate becomes oxaloacetate) and a NAD+ molecule reduces to become a NADH + H+, is the intermediate being oxidized when the hydrogen atoms are removed? Also, during Kreb's cycle when a CO2 is removed from isocitrate to form alpha ketoglutarate and when alpha ketoglutarate loses a CO2 and forms succinyl CoA, are the intermediates with CO2 removed undergoing decarboxylation? And the last question, when succinyl CoA phosphorylates GDP to GTP,  why is it that a inorganic phosphate group is combined with ADP to form ATP with the help of GTP? The textbook (Nelson Biology 12) and my teacher does not go into detail about that step of the Kreb's cycle, and I'm just curious.

In stages 1, 2, and 3 of cellular respiration (glycolysis, pyruvate oxidation and the kreb's cycle), every time that two hydrogen atoms are removed form a intermediate (eg. when malate becomes oxaloacetate) and a NAD+ molecule reduces to become a NADH + H+, is the intermediate being oxidized when the hydrogen atoms are removed?

Yes.

Also, during Kreb's cycle when a CO2 is removed from isocitrate to form alpha ketoglutarate and when alpha ketoglutarate loses a CO2 and forms succinyl CoA, are the intermediates with CO2 removed undergoing decarboxylation?

Yes. Decarboxylation is a chemical reaction which releases carbon dioxide (CO2).

when succinyl CoA phosphorylates GDP to GTP,  why is it that a inorganic phosphate group is combined with ADP to form ATP with the help of GTP? The textbook (Nelson Biology 12) and my teacher does not go into detail about that step of the Kreb's cycle, and I'm just curious.

After the GDP becomes charged, a separate chemical reaction removes the third phosphate from GTP to produce ATP via the use of phosphatases. But that is for an advanced biochemistry fourth year university class :P.

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