Molecular Function of Actin and Myosin

Actin

bunch of small proteins stringed together, they are the contractile filaments of muscle cells

G-Actin

small, individual proteins or monomers of Actin

F-Actin

entire Actins structure

The G-Actin’s have a _____________ , this is where the myosin

heads will bind for a muscle contraction

active site

The Actin’s active site is covered by a protein called

Active Site

the active site keeps the muscle

relaxed

Tropomyosin

made of 3 subunits, it controls the interactions between actin and myosin, it always binded to the Tropomyosin. It controls the movement of the Tropomyosin to expose the active site for muscle contraction and relaxation

The ion _____________ will bind to the other end of the

Troponin. This causes the Troponin to change shape and will

move the Tropomyosin off of the Active site.

calcium

When the Active sites are exposed, the ___________________

will bind to the active site and bend at the _____________, this

will cause a Power Stroke or a muscle contraction.

Myosin heads, Hinge

For every _____ Myosin, it can bind to _____ G-Actin active

sites.

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