MidTerm 1Muscle Contraction Mechanism Quiz 6

Which of the following is NOT involved in muscle contraction?

• Actin

• Myosin

• Troponin

• Acetylcholine

During muscle contraction, calcium ions bind to:

• Actin

• Myosin

• Troponin

• Acetylcholine

The release of calcium ions from the sarcoplasmic reticulum is triggered by:

• Acetylcholine

• ATP

• Norepinephrine

• Excitation-contraction coupling

What happens to the length of the sarcomere during muscle contraction?

• It shortens

• It lengthens

• It remains the same

• It oscillates

The power stroke in muscle contraction occurs when:

• Myosin heads detach from actin

• ATP binds to myosin heads

• Calcium ions are released

• Myosin heads pivot, causing actin to slide

Which molecule stores and releases calcium ions in muscle cells?

• Tropomyosin

• Troponin

• Sarcoplasmic reticulum

• Acetylcholine

What is the primary energy source for muscle contraction?

• Glucose

• Lactic acid

• ATP

• Creatine phosphate

Which of the following is responsible for breaking down ATP during muscle contraction?

• Myosin

• Actin

• ATP synthase

• Myosin ATPase

The sliding filament theory of muscle contraction proposes that:

• Actin filaments slide over myosin filaments

• Myosin filaments slide over actin filaments

• Actin and myosin filaments slide past each other

• Actin and myosin filaments remain stationary

The motor unit consists of:

• A motor neuron and the muscle fibers it innervates

• A single muscle fiber

• A group of motor neurons

• A muscle spindle and a golgi tendon organ