Question

When electrons join `NAD^+` and `FAD` during the Krebs cycle, what do they form?

Answer 1

When a species gains electrons, the species is said to be reduced. Both `NAD+` and `FAD` would become `NADH` and `FADH2` respectively.

Explanation:

Think about this. Acetyl CoA molecules are being oxidized in the process, so if oxidation occurs, reduction does too. What are being reduced? Well, NAD+ and FAD are. They are electron carriers that will participate in the electron transport chain.

These electron carriers molecules will pass on their electrons to ubiquinone and in exchange, protons will pass out to the intermembrane space. The proton gradient set up will be harnessed by ATP Synthase to release ATP molecules for the body to use as a form of energy to do work.