What two substances does anaerobic alactic metabolism utilize to create energy?

Anaerobic alactic metabolism, which occurs without the presence of oxygen and does not produce lactic acid as a byproduct, primarily relies on substrates that are readily available for energy production in high-intensity, short-duration activities. The correct choice highlights the role of creatine phosphokinase and glycogen in supplying this energy.

Creatine phosphokinase (CPK) helps regenerate adenosine triphosphate (ATP) from creatine phosphate in muscle cells, providing energy very rapidly for muscle contractions. This process is crucial during the initial stages of intense exercise when the body needs energy quickly.

Glycogen, stored in the muscles and liver, is broken down into glucose when needed, even in the absence of oxygen, to fuel energy production. Unlike other metabolic pathways that also utilize glucose, anaerobic alactic metabolism operates efficiently without excessive lactic acid buildup, allowing sustained muscle performance during short, sprint-like exertion.

Other substances listed in the incorrect options do not accurately describe the substrates used in this specific anaerobic energy pathway. Therefore, the combination of creatine phosphokinase and glycogen is essential for supplying immediate energy in anaerobic alactic conditions.