Algonquin College Health Program Assessment (AC-HPAT) Practice Exam

What is the role of pyruvate in cellular metabolism?

1. A carrier of oxygen

2. An energy storage molecule

3. An output of glycolysis

4. A waste product of respiration

The correct answer is: An output of glycolysis

Pyruvate plays a crucial role in cellular metabolism as it is the end product of glycolysis, a key metabolic pathway that breaks down glucose to extract energy. In glycolysis, one molecule of glucose is converted into two molecules of pyruvate, generating a small amount of ATP (the energy currency of the cell) and NADH in the process. Once formed, pyruvate can be further processed under aerobic conditions to enter the mitochondria, where it is transformed into acetyl-CoA, entering the citric acid cycle and leading to the production of more ATP. Alternatively, in anaerobic conditions, pyruvate can be converted into lactate or ethanol, depending on the organism, allowing for continued ATP production when oxygen is scarce. This significance as a product of glycolysis emphasizes pyruvate's central role in energy production and metabolism, which is why it is identified correctly as an output of glycolysis.