Which system is associated with the production of ATP without the presence of oxygen?

The anaerobic system is responsible for the production of ATP without the presence of oxygen. This energy system allows the body to generate energy quickly for high-intensity activities that last for a short duration, typically up to around 30 seconds. The anaerobic system primarily relies on stored energy sources in the muscle cells, such as phosphocreatine and glucose, to create ATP through processes like anaerobic glycolysis.

During anaerobic glycolysis, glucose is converted into pyruvate, and in the absence of oxygen, this process then leads to the production of lactic acid. This pathway enables the body to produce energy rapidly, making it essential during brief bursts of intense exercise—such as sprinting or heavy lifting—where oxygen supply cannot meet the energy demands.

In contrast, the aerobic system and oxidative system utilize oxygen to produce ATP, typically during longer-lasting, lower-intensity activities. These systems allow for sustained energy production but do not function effectively without oxygen, which is a key distinction from the anaerobic system.