Muscle Contraction: Cross Bridge Cycling Quiz

What triggers the sarcoplasmic reticulum to release calcium ions?

• Troponin

• Myosin

• Tropomyosin

• An action potential

What happens when calcium ions bind to troponin?

• Tropomyosin rolls off the myosin-binding sites

• Myosin head cocks

• Myosin pulls actin toward the M-line

• ATP binds to myosin

What is the role of troponin in muscle contraction?

• To change shape and roll tropomyosin off the myosin-binding sites

• To form a cross-bridge between myosin head and myosin-binding site

• To release calcium ions

• To block the myosin-binding sites

What is the name of the step where myosin pulls actin toward the M-line?

• Step 1

• Step 6

• Step 5

• Relaxed sarcomere

What is the function of ATP in cross bridge cycling?

• To grab actin

• To release actin

• To break the cross-bridge

• To pull actin toward the M-line

What is the memory hook for step 4 of cross bridge cycling?

• GRAB

• PULL

• ON

• RELEASE

What is the memory hook for step 5 of cross bridge cycling?

• PULL

• ON

• GRAB

• RELEASE

During which step of cross bridge cycling does the myosin head detach from actin?

• When ATP binds to myosin

• When calcium ions bind to troponin

• When myosin head cocks

• When myosin pulls actin toward the M-line

What is the role of the sarcoplasmic reticulum in muscle contraction?

• To store and release calcium ions

• To bind to myosin heads

• To produce ATP

• To block the myosin-binding sites

Which component of the muscle fiber is responsible for the striated appearance of skeletal muscle?

• Myosin

• Actin

• Sarcomere

• Sarcoplasmic reticulum