Sliding filament theory

What is the state of the muscle during the resting state?

• Contracted

• Relaxed

• Partially contracted

• Stretched

Where are calcium ions stored during the resting state of a muscle?

• Myosin heads

• Actin filaments

• Sarcoplasmic reticulum

• Troponin

What blocks the myosin binding sites on the actin filament during the resting state?

• Troponin

• Tropomyosin

• Calcium ions

• ATP

What triggers the release of calcium ions into the muscle fibre?

• Muscle relaxation

• Nerve impulse

• ATP synthesis

• Actin filament movement

What does calcium bind to in order to expose the myosin binding sites on actin?

• Myosin

• Tropomyosin

• Troponin

• ATP

What is formed when myosin heads attach to the binding sites on actin?

• Power stroke

• Cross-bridges

• Sarcomere

• ATP

What is the movement called when myosin heads pivot and pull actin filaments toward the centre of the sarcomere?

• Cross-bridge formation

• Muscle relaxation

• Power stroke

• ATP synthesis

What powers the power stroke in muscle contraction?

• Calcium ions

• ATP breakdown

• Troponin binding

• Nerve impulse

What happens to the muscle as a result of the sliding of actin past myosin?

• It elongates

• It shortens and generates force

• It remains the same length

• It relaxes

What is required for the detachment of myosin after the power stroke?

• Calcium ions

• A new molecule of ATP

• Troponin

• Nerve impulse