When a muscle is at rest, what blocks myosin from heading to actin?
Correct answer: A. Tropomyosin
- A. Tropomyosin
- B. Tubulin
- C. Troponin
- D. Sarcomere
Explanation
When a muscle is at rest, tropomyosin is a regulatory protein that covers the myosin-binding sites on the actin filament. This covering prevents the myosin heads from attaching to actin, effectively inhibiting muscle contraction. Tropomyosin's position is controlled by the troponin complex in response to calcium levels.
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About Support and Movement
Support and movement covers the axial and appendicular skeleton, bone structure, joints and the arrangement of skeletal muscles. Muscle contraction is explained through actin, myosin, sliding filaments, calcium ions and ATP, while arthritis is distinguished as a disorder of joints rather than a normal part of movement.
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