LESSON 2: PYRUVATE OXIDATION
The next part of cellular respiration occurs in a new part of the cell called the mitochondria. You may remember that this is one of the organelles in a cell that is referred to as the "powerhouse". This term comes from the high amount of ATP, evidently what provides us with energy or "power", that is generated within the mitochondria.
When oxygen is available, the 3 carbon pyruvate produced in glycolysis is transported to the mitochondrial matrix. 1 of the 3 carbons is removed from the molecule in the form of carbon dioxide (CO2) through a decarboxylation reaction. Think of that time right before summer and at the end of spring when your dad asks you to de-weed the lawn. The prefix "de-" literally means removing or taking away. In the case of de-weeding, you are "taking away" weeds from the yard but the root word in decarboxylation is "carboxyl" which comes from carbon. Thus, this should be a tool in helping you remember what exactly happens in a decarboxylation reaction; the "taking away" of a carbon as CO2. Next, another "bank payment" is made as it was in glycolysis and 1 H is removed from the pyruvate and added to NAD+ to form NADH through an oxidation reaction. The last step in pyruvate oxidation involves the addition of the carrier molecule called coenzyme A (CoA). The final product of this reaction is called an Acetyl-Coenzyme A molecule made of 2 carbons (Acetyl CoA).