Final answer:
Without lactate dehydrogenase, muscle cells would struggle with anaerobic energy production during strenuous activity, leading to rapid fatigue and impaired muscle performance.
Step-by-step explanation:
If skeletal muscle cells lacked lactate dehydrogenase (LDH), it would impair strenuous muscular activities. During high-intensity exercise when oxygen is insufficient, muscle cells rely on anaerobic glycolysis to produce ATP—the energy currency of cells—with lactic acid being a by-product. LDH catalyzes the conversion of pyruvic acid into lactic acid and back, allowing muscles to continue producing energy anaerobically. Without LDH, there would be a buildup of pyruvate and a decrease in ATP production under anaerobic conditions, leading to rapid fatigue and decreased muscle function.
Moreover, without LDH, lactic acid would not be converted back to pyruvic acid and sent to the liver for further metabolism, which may impede the muscles' ability to recover post-exercise. Consequently, the inability to engage in effective anaerobic activity without LDH would significantly limit one's ability to perform strenuous muscular activity.