Sliding Filament

___slides inward during muscle contraction.

• actin

• myosin

When ATP binds to the myosin head the myosin head then _____________.

• completes a power stroke

• attaches to actin

• rotates

• detaches from actin

___are regulatory proteins that cover the myosin binding site on the actin.

• troponin-tropomyosin

• sarcomere

• sarcolemma

• sarcoplasmic reticulum

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

• Yes

• No

What state is the sarcomere in

• Relaxed

• Contracting

• Fully Contracted

• None of the above

What state is the sarcomere in

• Relaxed

• Contracting

• Fully Contracted

• None of the above

Thick filaments within a myofibril are:

• ATPase

• Sarcoplasmic reticulum

• Actin

• Myosin

Thin filaments in a myofibril are

• Sarcomeres

• Sarcoplasm

• Actin

• Myosin

The sliding filament theory of muscle contraction says

• Actin and myosin filaments condense, thus causing the filament to shorten which in turn shortens the muscle

• Myosin rotates and wraps actin around it making the muscle shorter

• Friction is reduced between thin and thick filaments causing the thick filaments to move inside the thin

• Actin filaments slide over myosin filaments, making the muscle shorter

Which number represents the myosin filament?

• 1

• 2

• 3

• 4