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

What is another by-product of cellular respiration besides carbon dioxide?

1. Glucose

2. Oxygen

3. Water

4. Adenosine triphosphate (ATP)

The correct answer is: Water

The by-product of cellular respiration, besides carbon dioxide, is water. During the process of cellular respiration, glucose is broken down with the help of oxygen to produce energy. This metabolic process takes place in several stages, including glycolysis, the citric acid cycle, and the electron transport chain. In the final stages of cellular respiration, specifically during the electron transport chain, electrons are transferred and ultimately combine with oxygen, which is the terminal electron acceptor. This reaction also involves protons, leading to the formation of water as a crucial by-product. Thus, water is a significant output alongside the main product, adenosine triphosphate (ATP), which is the energy currency of the cell. Understanding the by-products of cellular respiration helps clarify the role of respiration in ecosystems, where both carbon dioxide and water produced are vital for plant processes, maintaining balance in the environment.