Actin and Myosin

Do the lengths of the thick and thin filaments change during contraction?

• Yes

• No

Actin is the ...

• Thick Filament within a Muscle Fibre

• Thin Filament within a Muscle Fibre

• Protein that covers myosin-binding sites

• Molecule that causes muscle contraction

Myosin is the ...

• Thin Filament of a muscle fibre

• Segment of a muscle fibre

• A molecule that changes shape when bound with Calcium Ions

• Thick Filament of a muscle fibre

The Z Line provides attachment for the ...

• Troponin

• Myosin

• Actin

• ATP

True or False: Myosin-Heads act as a ATPase.

• True

• False

What is necessary for the myosin to release the actin?

• ATP

• Calcium

• ADP

• Sodium

What does the myosin do to the actin?

• Nothing

• Pushes on it

• Pulls on it

• Breaks it into pieces

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

How does the sarcomere shorten (contract) ?

• The myosin filaments contract

• The actin filaments contract

• The myosin is pulled by the actin

• The actin is pulled by the myosin

What is the name of structure #2?

• Troponin

• Tropomyosin

• Actin

• ATP