Which of the following is an indication that aerobic training has improved cellular metabolism?

• A. Increased mitochondrial density in muscle cells
• B. Decreased oxygen uptake during exercise
• C. Lower levels of enzymes involved in the citric acid cycle
• D. Reduced production of ATP in the presence of oxygen

Answer: (A)

Verified step by step guidance

1. Understand the context of aerobic training: Aerobic training enhances the ability of cells to use oxygen efficiently for energy production. This involves improvements in cellular structures and metabolic pathways.
2. Review the role of mitochondria: Mitochondria are the organelles responsible for aerobic respiration, where oxygen is used to produce ATP. Increased mitochondrial density in muscle cells is a key adaptation to aerobic training, as it allows for more efficient energy production.
3. Analyze oxygen uptake during exercise: Aerobic training typically increases oxygen uptake efficiency, not decreases it. A decrease in oxygen uptake would indicate reduced aerobic capacity, which is contrary to the effects of training.
4. Examine enzymes involved in the citric acid cycle: Aerobic training generally increases the levels and activity of enzymes involved in the citric acid cycle, as this cycle is central to aerobic energy production. Lower levels of these enzymes would suggest impaired metabolism.
5. Evaluate ATP production in the presence of oxygen: Aerobic training enhances ATP production in the presence of oxygen, as it improves the efficiency of oxidative phosphorylation. Reduced ATP production would indicate a decline in metabolic function, which is not a result of aerobic training.