National League for Nursing (NLN PAX) Practice Exam

Cellular respiration is a metabolic process in which cells convert nutrients, primarily glucose, into energy in the form of adenosine triphosphate (ATP). During this process, cells utilize oxygen to break down glucose, producing energy, water, and carbon dioxide as byproducts. The primary gas released during cellular respiration is carbon dioxide, which is a direct result of the deoxidation of glucose.

When glucose is metabolized, it undergoes a series of reactions in the mitochondria, where oxygen is consumed, and carbon dioxide is formed. This carbon dioxide is then expelled from the cell and eventually exhaled by an organism.

While oxygen is consumed during cellular respiration, it is not released; instead, it is used in the process. Hydrogen is also involved in biochemical reactions but does not represent a significant gas produced in notable amounts during cellular respiration, nor is nitrogen primarily associated with this process. Thus, the release of carbon dioxide is emblematic of the cellular respiration process, confirming it as the correct answer.