Is oxygen necessary to convert pyruvate into acetyl CoA?

Question

and how so?

Answer 1

yes it is

Answer 2

Oxygen does not take part directly in the pyruvate dehydrogenase reaction , i.e., ..pyruvate to acetyl CoA. Pyruvate is oxidatively decarboxylated using the oxidizing power of NAD+. The NADH that is formed is recycled back to NAD+ by oxidation through the respiratory chain with oxygen as the terminal electron acceptor. So the initial reaction,  conversion of pyruvate to acetyl CoA which occurs in the mitochondrion via PDH does NOT require oxygen...but subsequent oxidation of the NADH to NAD+ to keep PDH working requires the Electron transport system and hence the oxygen