Optometry Admission Test (OAT) Practice

During what process is pyruvate decarboxylation converted to acetyl CoA?

1. The citric acid cycle

2. Oxidative phosphorylation

3. Electron transport chain

4. Within the mitochondrial matrix

The correct answer is: Within the mitochondrial matrix

Pyruvate decarboxylation is a vital metabolic process that occurs in the mitochondrial matrix, where pyruvate is converted into acetyl CoA. During this conversion, one carbon atom is removed from pyruvate, releasing it as carbon dioxide, while the remaining two-carbon molecule is combined with coenzyme A to form acetyl CoA. This process is crucial as acetyl CoA serves as a key substrate for the citric acid cycle, which plays an important role in cellular respiration and energy production. The mitochondrial matrix is the site of many critical metabolic reactions, particularly those involving the breakdown of carbohydrates, fats, and proteins. By completing pyruvate decarboxylation in the mitochondrial matrix, the cell efficiently channels the products into further metabolic pathways. This specialization of the matrix is what distinguishes it from the processes that occur in other parts of the cell, such as the electron transport chain and oxidative phosphorylation, which take place in the inner mitochondrial membrane and are subsequent steps in cellular respiration following the production of acetyl CoA. In summary, the mention of the mitochondrial matrix accurately identifies where pyruvate decarboxylation occurs, highlighting its importance in converting pyruvate into a usable form of energy as acetyl