Question

During muscular contraction, the myosin head binds to the exposed active sites on actin to form a?

• A. Motor unit
• B. Motor end plate
• C. Cross bridge
• D. None of the above

Answer 1

Answer: (C)

Cross bridge

C. Cross bridge

EXPLANATION: During muscle contraction cycle the energy released during ATP hydrolysis, which changes the angle of the myosin head into a 'cocked' position. During this time myosin is ready to bind to actin if the sites are available. As soon as the actin-binding sites are uncovered, the high-energy myosin head bridges the gap and forms cross-bridge.