What are the immediate products of ATP breakdown in muscle contraction?

What are the immediate products of ATP breakdown in muscle contraction?

• A. ADP+Pi
• B. ATP
• C. NADH
• D. FADH2

Answer: (A)

During muscle contraction, the energy for the movement comes from ATP being hydrolyzed. When ATP is split, it becomes ADP plus inorganic phosphate (Pi). This immediate product pair provides the energy that powers the myosin head’s movement and the cross-bridge cycling; the phosphate is released to help drive the power stroke, and ADP stays attached until a new ATP binds to reset the cycle. The other options aren’t produced in this step: ATP is the fuel being used, not a product; NADH and FADH2 are electron carriers made in other parts of cellular respiration, not from ATP breakdown.

During muscle contraction, the energy for the movement comes from ATP being hydrolyzed. When ATP is split, it becomes ADP plus inorganic phosphate (Pi). This immediate product pair provides the energy that powers the myosin head’s movement and the cross-bridge cycling; the phosphate is released to help drive the power stroke, and ADP stays attached until a new ATP binds to reset the cycle. The other options aren’t produced in this step: ATP is the fuel being used, not a product; NADH and FADH2 are electron carriers made in other parts of cellular respiration, not from ATP breakdown.