Which substance is primarily used for oxygen storage in muscle cells?

Which substance is primarily used for oxygen storage in muscle cells?

• A. Creatine kinase.
• B. A carbohydrate stored in the liver.
• C. A lipid involved in membrane structure.
• D. Myoglobin.

Answer: (D)

Muscle cells rely on stored oxygen to sustain aerobic metabolism during contraction, especially at the onset of activity. Myoglobin, a small heme-containing protein in muscle, binds oxygen from the blood and holds it in reserve, releasing it to mitochondria as demand rises. This makes it the primary oxygen storage system in muscle tissue, ensuring a local oxygen supply even when blood flow hasn’t ramped up yet. Creatine kinase drives rapid ATP regeneration from phosphocreatine, not oxygen storage. A carbohydrate stored in the liver provides glucose for energy, not oxygen. A lipid involved in membrane structure serves a structural role, not oxygen storage. So, myoglobin best explains how oxygen is stored in muscle cells.

Muscle cells rely on stored oxygen to sustain aerobic metabolism during contraction, especially at the onset of activity. Myoglobin, a small heme-containing protein in muscle, binds oxygen from the blood and holds it in reserve, releasing it to mitochondria as demand rises. This makes it the primary oxygen storage system in muscle tissue, ensuring a local oxygen supply even when blood flow hasn’t ramped up yet. Creatine kinase drives rapid ATP regeneration from phosphocreatine, not oxygen storage. A carbohydrate stored in the liver provides glucose for energy, not oxygen. A lipid involved in membrane structure serves a structural role, not oxygen storage. So, myoglobin best explains how oxygen is stored in muscle cells.