When a muscle has been repeatedly contracting at a moderate intensity for an extended period of time (more than a few minutes), what is the primary source of ATP?
A) transfer of energy and phosphate from creatine phosphate to ADP
B) glycolysis
C) oxidative phosphorylation
D) breakdown of myosin
E) uptake of ATP from the blood plasma

Question

Quizplus · Accepted Answer

When a muscle has been repeatedly contracting at a moderate intensity for an extended period of time, the primary source of ATP is through oxidative phosphorylation. This process takes place in the mitochondria and relies on the presence of oxygen to generate ATP through the electron transport chain. Glycolysis and the breakdown of myosin may also contribute to ATP production, but they are not the primary sources in this situation. The transfer of energy and phosphate from creatine phosphate to ADP and the uptake of ATP from the blood plasma are short-term sources of ATP, not suitable for prolonged muscle contractions.

When a Muscle Has Been Repeatedly Contracting at a Moderate