Sarcomere & Mechanism of muscle contraction

During full muscle contraction, which region disappear?

• I band

• M line

• H zone

• A band

Which part separate one sarcomere to the next?

• M line

• I band

• H zone

• Z line

What is a crossbridge?

• Where myosin head binds to myosin binding site on actin

• Where the calcium ion crosses into the sarcoplasm

• Where calcium ion binds with troponin complex

• None of the answers are correct.

What state is the sarcomere in #1

• Relaxed
• Contracting
• Fully Contracted
• None of the above

Ca²⁺ released by sarcoplasmic reticulum will bind to ____

• Actin

• Troponin

• Myosin

• Tropomyosin

When power stroke in muscle contraction will occur?

• ATP binds to myosin head

• Myosin head releases ADP and Pi

• Myosin head hydrolyse ATP

• Myosin binds to actin

What is the name of the thin myofilaments in the muscle cell?

• Actin
• Myosin
• Myoglobin
• Titan

What is the name of the thick myofilaments?

• Actin
• Myosin
• Myoglobin
• Titan

What is the structure that stores the calcium ion in the muscle cell?

• Sarcoplasm

• Sarcolemma

• Myoglobin

• Sarcoplasmic Reticulum

What is sarcomere?

• A protein filament or fiber
• The functional unit of muscle fiber in the skeletal muscle

• An organelle
• An organ