During activities requiring aerobic endurance Select one:
A. fatigue occurs in a few minutes.
B. oxygen debts are common.
C. oxygen is not required.
D. glycogen and glycolysis are the primary sources of reserve energy.
E. most of the muscle’s energy is produced in mitochondria.
The correct answer and explanation is:
The correct answer is E. most of the muscle’s energy is produced in mitochondria.
Explanation:
During activities requiring aerobic endurance, the body primarily relies on aerobic metabolism to produce energy. Aerobic metabolism uses oxygen to convert carbohydrates, fats, and sometimes proteins into adenosine triphosphate (ATP), which is the energy currency for muscle contraction. This process takes place in the mitochondria, which are often called the “powerhouses” of the cell because they efficiently generate large amounts of ATP through the aerobic respiration pathway.
Aerobic endurance activities are typically moderate-intensity exercises sustained over long periods, such as long-distance running, swimming, or cycling. In these activities, oxygen supply to the muscles is adequate, allowing aerobic respiration to dominate energy production. The mitochondria use oxygen to break down glucose, fatty acids, and amino acids to produce ATP in a way that is much more efficient than anaerobic processes.
Option A is incorrect because fatigue from aerobic activities generally develops gradually, over longer periods, not within a few minutes. Option B is incorrect because oxygen debts are more typical of anaerobic activities when oxygen supply temporarily cannot meet demand. Option C is incorrect because oxygen is required in aerobic endurance activities. Option D is incorrect because glycogen and glycolysis are more involved in anaerobic metabolism or short-term energy needs, while aerobic endurance relies more on mitochondrial oxidative phosphorylation.
Therefore, in aerobic endurance, the sustained supply of oxygen allows mitochondria to be the primary site of ATP production, supporting prolonged muscle activity efficiently.