Muscle/StructureofMuscle/TheThinFilament

The Thin Filament

The thin filament is made up of two intertwined helical chains of the globular protein actin.

Within the sarcomere the thin filament is arranged so the binding sites on the actin monomers are able to interact with myosin heads of the thick filament.

Besides actin there are two other accessory proteins associated with the thin filament. Tropomyosin is an elongated protein that spans 7 actin molecules. Troponin is a protein made up of three subunits and is attached to tropomyosin. Together these two accessory proteins “block” the myosin head from attaching to the binding site on the actin.

Challenge Quiz

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<GIFT> //LEVEL:2 //RAND The thin filament is made up of two helically intertwined chains of {myosin~=actin}.

//LEVEL:2 //RAND The binding site on the actin molecule is for {=myosin~troponin}.

//LEVEL:2 //RAND Troponin and tropomyosin are known as accessory proteins for the thin filament {=True~False}

//LEVEL:2 //RAND Troponin is an elongated protein that spans 7 actin molecules {True~=False}

//LEVEL:2 //RAND Troponin and tropomyosin together hold the thin filament together {True~=False}