Mechanism of Muscle Contraction

What is the length between Z-lines of an actin molecule called?

• fascicle

• sarcomere

• myosin binding site

• sarcoplasmic length

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 a crossbridge?

• Where myosin binds to actin

• Where the calcium crosses into the cytoplasm

• Where calcium binds with troponin

• Where titin and myosin are connected

What is the name of the protein that covers the binding sites on actin?

• Myosin

• Titin

• Troponin

• Tropomyosin

What does the sarcoplasmic reticulum do?

• Stores sodium

• Stores ATP

• Releases sodium

• Stores calcium

When a muscle is in a contracted position, what is the relationship between actin filaments?

• They are on top of one another

• They are beside each other

• They are close to each other

• They are far apart from each other

When a muscle is relaxed and in a lengthened position, what is the relationship between actin filaments?

• They are on top of one another

• They are beside each other

• They are close to each other

• They are far apart from each other

What two chemicals are necessary for muscle contraction to occur?

• Niacin and Potassium

• Calcium and ATP

• Sodium and Potassium

• Acetylcholine and Potassium

Tags

NGSS.HS-LS1-7

___ and ___ are regulatory proteins bound to actin.

• Myosin and actin

• Glycogen and hemoglobin

• Calcium and oxygen

• Troponin and tropomyosin