The lactic acid energy system is also known as what?

• A. Aerobic metabolism
• B. Anaerobic glycolysis
• C. Oxidative phosphorylation
• D. Beta-oxidation

Answer: (B)

The lactic acid energy system refers to anaerobic glycolysis, the rapid pathway used when exercise intensity is high and oxygen delivery can’t meet demand. In this system, glucose is broken down in the cytoplasm to pyruvate through glycolysis, yielding ATP quickly. When oxygen is limited, pyruvate is converted to lactate by lactate dehydrogenase, which regenerates NAD+ so glycolysis can continue and produce ATP for a short time. The result is a quick energy boost for high-intensity efforts, but lactate and hydrogen ions build up and contribute to fatigue, limiting how long it can be sustained. This differs from aerobic metabolism, which uses oxygen to drive oxidative phosphorylation for much greater ATP production over longer periods. Beta-oxidation involves fat breakdown and is not part of this quick, lactate-producing pathway.