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

Which type of respiration occurs when oxygen is present?

1. Anaerobic Respiration

2. Aerobic Respiration

3. Fermentation

4. Glycolysis

The correct answer is: Aerobic Respiration

Aerobic respiration is the process that occurs when oxygen is present, and it plays a crucial role in the energy production of many living organisms. This type of respiration utilizes oxygen to fully break down glucose into carbon dioxide and water, resulting in the release of a significant amount of energy, measured in ATP (adenosine triphosphate). During aerobic respiration, the glucose molecule is first converted through glycolysis into pyruvate in the cytoplasm. Subsequently, in the presence of oxygen, pyruvate enters the mitochondria, where it undergoes further processing through the Krebs cycle and the electron transport chain. These stages collectively optimize energy extraction from glucose, making it a highly efficient pathway for ATP production. Other processes listed, such as anaerobic respiration and fermentation, occur without oxygen and result in less energy production. While glycolysis is the initial step for both aerobic and anaerobic pathways, it does not define the presence or absence of oxygen during respiration. Therefore, the characteristic of requiring oxygen directly supports the categorization of aerobic respiration as the answer.