Question

Which property of muscle fibres enable them to cause movement?

Answer 1

• Myofibril activity is required for muscle contraction on the molecular level.
• When ATP binds to myosin, it separates from the actin of the myofibril, which causes a contraction.
  
• The muscle contraction cycle is triggered by calcium ions binding to the protein complex troponin, exposing the active-binding sites on the actin.
  
• ATP then binds to myosin, moving the myosin to its high-energy state, releasing the myosin head from the actin active site.
• When ATP is exhausted lactic acid is produced

So, the correct answer is 'contraction'.