Steps of Muscle Contraction

The act of the myosin pulling the actin in a muscle contraction is called a ____.

• cross bridge

• power stroke

• action potential

• tendon

Calcium:

• causes ATP binding to actin

• increases the action potential along the sarcolemma

• binds to proteins on myosin

• triggers the binding of myosin to actin

What state is the sarcomere in #2

• Relaxed

• Contracting

• Fully Contracted

• None of the above

___ and ___ are regulatory proteins bound to actin. 

• Troponin and tropomyosin

• Myosin and actin

• Calcium and Oxygen

• Glycogen and hemoglobin

What is a crossbridge?

• Where myosin binds to actin

• Where the calcium crosses into the cytoplasm

• Where calcium binds with troponin

• None of the answers are correct.

Calcium binds to ___of the troponin-tropomyosin complex.

• troponin

• tropomyosin

• actin

• myosin

What does the myosin do to the actin?

• Nothing

• Pushes on it

• Pulls on it

• Breaks it into pieces

What does calcium do to the actin?

• Covers myosin binding sites

• Uncovers myosin binding sites

• Covers actin binding sites

• Uncovers actin binding sites

What is the role of ATP in muscle contraction?

• Provides energy for the power stroke

• Binds to actin to initiate contraction

• Releases calcium from the sarcoplasmic reticulum

• Inhibits the binding of myosin to actin

Tags

NGSS.HS-LS1-7

Which ion is essential for muscle contraction to occur?

• Sodium

• Potassium

• Calcium

• Magnesium