CSSD Practice Exam 2025 – Complete Study Resource

Muscle glycogen plays a crucial role in meeting the body’s energy demands, particularly during exercise. It is stored in the muscles and serves as a rapidly available source of energy. When the body requires energy, especially during high-intensity activities, muscle glycogen is broken down into glucose molecules. This process allows for the swift generation of ATP (adenosine triphosphate), the energy currency of the cell.

The reason why this answer is particularly relevant relates directly to the primary function of glycogen in energy metabolism. Glycogenolysis, the process through which glycogen is converted to glucose, occurs when muscle energy demands increase. The glucose derived from glycogen can then be utilized to fuel muscle contractions, especially in anaerobic (non-oxygen dependent) situations, where the energy needs exceed the available oxygen supply.

The other options do not accurately represent the primary function of muscle glycogen. Muscle glycogen does not serve as a source of fatty acids, nor is it primarily converted into protein. Additionally, while muscle glycogen is used in anaerobic processes, it is not exclusively limited to that; it also supports aerobic metabolism when sufficient oxygen is available. Therefore, the essential role of muscle glycogen in releasing glucose for energy aligns with