A Explain which stages of metabolism include NADH and FADH2

A. Explain which stages of metabolism include NADH and FADH2 production.

NADH:

FADH2:

B. What occurs if NADH and FADH2 are not oxidized in the electron transport chain?

Solution

A. Explain which stages of metabolism include NADH and FADH2 production.

NADH:

Glycolysis

Glyceraldehyde 3 phosphate------------> 1,3 bisphosphoglycerate + NADH

Citric acid cycle:

Isocitrate----------->Alpha ketoglutarate + NADH

Alpha ketoglutarate-------------> Succinyl CoA + NADH

Malate------------> Oxaloacetate + NADH

FADH2:

Citric acid cycle:

Succinate---------> Fumarate

B. What occurs if NADH and FADH2 are not oxidized in the electron transport chain?

Cell needs constant supply of NAD+ to keep glycolysis running. Under anaerobic conditions NADH that is generated during glycolysis cannot be oxidized in mitochondria to NAD+, therefore cell switches to lactate fermentation.

During lactate fermentation, lactate dehydrogenase reversibly converts pyruvate to lactate by using up NADH. This regenerated NAD+ which is then used in glycolysis; supplies energy when oxygen for aerobic respiration is scarce.