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Cellular Respiration
Transition Reaction
Home | Glycolysis | Krebs Cycle | Electron Transport Chain | Transition Reaction

The transition reactions takes place in the matrix of the mitochondria and is the official start to aerobic respiration. This process will continue as long as there are sufficient amounts of oxygen present in the mitochondria. In the case of not having sufficient amounts of oxygen, fermentation will begin.
Pyruvate which is created in glycolysis, pentrates through the externel mitochondrial membrane and enters into the matrix by a protein located on the external membrane. Once the molecule has reached into the matrix, a complex enzyme called pyruvate-dehydrogenase helps with the process of oxidative decarboxylation. NAD+ takes on two electrons that oxidates pyruvate, then releasing CO2. A two carbon molecule known as acetyl is formed. It then immediately bonds with a coenzyme called coenzyme A to form acetyl CoA.
Acetyl Co-A is the main product that begins the next process in cellular repiration. The next product is the kreb cycle. This stage is where sugars provide the necessary acetyl to produce ATP or acetyl Co-A can be formed through the break down of fats and proteins. If there's to much ATP, the acetyl co-a is directed to other metabolic pathways such as the production of fatty acids necessary in the production of fats.

If acetly Co-A is not formed after glycolysis then cellular respiration stops.


Transition Reaction
Picture By : Yousef A.