Thin Filaments [Actin,Troponin,Tropomyosin]

In the unstimulated muscle, the position of the tropomyosin ____the binding sites on the ____subunits & ____myosin cross bridge building.

-Covers -Actin -Prevents

How is ACTIN arranged?

Actin is arranged in 2 single strands that intertwine helically & give them their shape.

What is ACTIN?

Actin is the major component of the thin filament.

What is the binding site?

Myosin

To ___the binding sites for binding with myosin, the tropomyosin molecule must be moved aside. ____aids in ____of the binding sites.

-Expose -Troponin -Exposure

What does each ACTIN protein subunit contain?

Each actin protein subunit contains a myosin--binding site.

What is TROPOMYOSIN?

The regulatory protein, tropomyosin is also part of the thin filament

What entwines around the ACTIN?

Tropomyosin entwines around the actin.

Troponin, by itself,_____move____away from the binding site on actin. This process requires _____. After an action potential, _____are released from the ____& bind to the _____. This causes a _____in the tropomyosin-troponin complex, "dragging" the _____off the binding sites.

-Cannot -Tropomyosin -Calcium ions -Calcium ions -Terminal cisternae -Troponin -Conformational change -Tropomyosin strands

What is TROPONIN?

Located @ regular intervals on the surface of tropomyosin.