[Campbell Biology P.1186] Based on the provided text, which two of the following are major fu... | Practice Question

Based on the provided text, which two of the following are major functions of ATP hydrolysis in skeletal muscle activity?

  • A: Initiating action potentials in muscle fibers.
  • B: Energizing myosin heads for cross-bridge formation.
  • C: Facilitating the detachment of myosin from actin.
  • D: Triggering the release of Ca2+ from the sarcoplasmic reticulum.
  • E: Activating the troponin complex.

Explanation

The text explicitly states: 'Myosin heads, energized by the hydrolysis of ATP, bind to the thin filaments, form cross-bridges, and then release upon binding ATP anew.' This highlights two crucial roles of ATP: providing energy to the myosin heads for their movement cross-bridge formation and enabling the detachment of myosin from actin, which is necessary for repeated cycles of contraction.