PQ 6.4 THE SLIDING FILAMENT THEORY OF MUSCLE CONTRACTION

What is the basic mechanism involved in muscle contraction?

• Muscles push on the bones

• Muscles pull on the bones

• Muscles remain the same length

• Muscles contract and relax

What causes the filaments to slide in muscle contraction?

• Release of calcium ions

• Presence of troponin and tropomyosin

• Interaction of myosin and actin molecules

• Detachment of myosin from actin molecule

What is the energy source for muscle relaxation?

• Adenosine Triphosphate (ATP)

• Calcium ions

• Myosin crossbridges

• Troponin and tropomyosin

What is the role of ATP in muscle contraction?

• To release calcium ions

• To facilitate interaction of myosin and actin molecules

• To detach myosin from actin molecule

• To replenish energy for muscle contraction

What is the sliding filament theory of muscle contraction?

• Muscles contract by shortening

• Muscles push on the bones

• Filaments overlap and slide relative to each other

• Filaments detach and reattach in rapid succession

What is the trigger mechanism for the sliding filament process?

• Release of myosin crossbridges

• Presence of troponin and tropomyosin

• Release of calcium ions

• Detachment of myosin from actin molecule

What is the function of myosin crossbridges in muscle contraction?

• To release calcium ions

• To facilitate interaction of myosin and actin molecules

• To detach myosin from actin molecule

• To create obstacles for muscle contraction

What is the role of troponin and tropomyosin in muscle contraction?

• To release calcium ions

• To facilitate interaction of myosin and actin molecules

• To detach myosin from actin molecule

• To create obstacles for muscle contraction

What is the process called when the muscle fibre contracts?

• Excitation-contraction coupling

• Myosin crossbridge detachment

• Filament sliding

• Muscle relaxation

What is the energy-carrying molecule used for muscle relaxation?

• Adenosine Triphosphate (ATP)

• Calcium ions

• Myosin crossbridges

• Troponin and tropomyosin