Question

During FERMENTATION when is NADH oxidized to NAD+?

Answer 1

NADH is oxidized once the electron acceptor accepts an electron from it and oxidizes it into NAD+.

For example:
In alcoholic fermentation, the electron acceptor is acetaldehyde. So it accepts an electron and NADH becomes NAD+.

In lactic acid fermentation, pyruvate is the electron acceptor. It “accepts” an electron from NADH and it becomes NAD+.

Process repeats until oxygen is present.

Hope that helps and have a great day! :)