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Cellular Respiration
Transition Reactions

Home | Key Terms/ Key Words | What happens before cellular respiration? | Glycolysis | Transition Reactions | Kreb's Cycle | The electron transport chain | Fermentation

The Second Phase Of Cellular Respiration

The transition reactions take place in the matrix of the mitochondrion. The process will always continue to take place as long as there is a sufficient amount of oxygen in the mitochondrion.
Pyruvate enters the matrix by a protein located on the external membrane. NAD takes two electrons that oxidizes pyruvate and releases carbon dioxide. The two carbon molecule, acetyl bonds with a coenzyme called coenzyme A and forms acetyl CO-A.
Acetyl CO-A is what begins the Kreb's cycle. Sugars provide the acetyl to produce ATP.
Directly after gylcolysis, if acetyl CO-A is not formed cellular respiration will stop. Meaning the organism will die.


Pyruvate - (NADH is added) - Acetyl - (Bonds with coenzyme A) - Acetyl CO-A