Question

Now that we have made it through two redox reactions we wonder what might be coming next. One off our classmates notices we have a phosphoryl group attached to our succinyl-CoA ride. Someone points out that this is a perfect time for another substrate level phosphorylation and indeed the next reaction does just that.

1. What was produced from this substrate level phosphorylation?

We now notice just how close we are to the cytoplasmic membrane. In fact we can even see the famous complex II of the electron transport chain. Our succinate molecule is oxidized to fumarate and we see the electrons are transfer to a component of complex II called FADH

2. What does FADH become when it is reduced?

We realize we are nearing the end of the cycle as our fumarate is converted to malate. One more redox reaction and we will be back on oxaloacetate and have to start the cycle all over again. We decide we would rather follow the electrons and see what’s happening in the cytoplasmic membrane so we all jump from malate to NAD+ as it is being reduced. Our classmates behind us follow along on their own NADH.

3. Now that everyone has made it through the Krebs cycle what have we produced?

Answer 1

Answer - 1

Substrate level phosphorylation is the a metabolic reaction that lead to the production of ATP by converting high energy substrate into low level product.

Answer-2

FADH become FADH2 when it is reduced because of the addition of electron.

Answer - 3

The citric acid or Kreb cycle produce in total- 6NADH + H+ molecule, 2 FADH2 molecule, 4 CO2, and 2 ATP.