Does citric acid cycle require oxygen?

1 Answer
Jun 17, 2014

Hello; no, in and of itself, the TCA or citric acid cycle does not use oxygen. Instead, it requires acetyl CoA, a 2-carbon molecule, that will combine (merge) with oxaloacetic acid (a four-carbon organic acid) to make the six-carbon molecule citrate (citric acid).

This is a cycle. Hence, that means what?

Oxaloacetic acid will be regenerated. Carbon dioxide (2 molecules) will be produced (or given off). And, finally, ATP and NADH molecules are also made.

The crucial link here is the ATP and NADH. Oxygen plays no part in this Kreb's or Citric Acid cycle.

When does oxygen play a role? In the next stage....if all conditions in the cell are appropriate, oxygen will be found at the 'end' of the electron transport chain in the inner mitochondrial membrane of Eukaryotes and the plasma membrane of Prokaryotes.
Oxygen's presence is useful why?