What is the primary source of ATP for cardiac muscle contraction?

• A. Glycolysis
• B. Oxidative phosphorylation
• C. Fermentation
• D. Creatine phosphate

Answer: (B)

Verified step by step guidance

1. Understand the role of ATP in muscle contraction: ATP is the energy currency of the cell, and it is crucial for muscle contraction, including cardiac muscle.
2. Identify the primary sources of ATP: ATP can be generated through several pathways, including glycolysis, oxidative phosphorylation, fermentation, and the use of creatine phosphate.
3. Evaluate the efficiency and capacity of each ATP source: Oxidative phosphorylation is the most efficient and sustainable source of ATP, especially for tissues with high energy demands like cardiac muscle.
4. Consider the oxygen availability: Cardiac muscle has a continuous supply of oxygen, which is necessary for oxidative phosphorylation to occur.
5. Conclude that oxidative phosphorylation is the primary source of ATP for cardiac muscle contraction due to its efficiency and reliance on oxygen, which is abundantly available in the heart.