Muscle Contraction

Which protein is primarily responsible for the contraction in the sliding filament theory?

• a) Troponin

• b) Myosin

• c) Actin

• d) Tropomyosin

In the sarcomere, what is the dark band called?

• A-band

• I-band

• H-band

• Z-band

What is the light band in the sarcomere called?

• X band
• Z band
• Y band
• I band

Which molecule covers the active sites on actin, preventing myosin from binding in a resting muscle?

• Actinomycin
• Myoglobin
• Tropomyosin
• Troponin

What is the functional unit of a muscle fibre where contraction occurs?

• Mitochondria
• Nucleus
• Cell membrane
• Sarcomere

What structure separates one sarcomere from the next in a myofibril?

• A band

• I band

• Z line

• M line

During muscle contraction, what happens to the length of the sarcomere?

• a) Shortens

• b) Lengthens

• Stays the same

Which ion plays a crucial role in initiating muscle contraction by binding to troponin?

• Sodium

• Potassium

• Chloride

• Calcium

What is the role of ATP in the sliding filament theory?

• Initiates muscle contraction

• Allows myosin to release from actin

• Inhibits troponin binding

• Causes muscle relaxation