Answer
Thin filaments
Thin filaments are 7-8 nm in diameter. They consist of two intertwined molecules of fibrous actin( F-actin). Each of these F-actin molecule is like a bead necklace -- a string with subunits of molecules of G globular fibrin (G-fibrin) molecules.
Work Step by Step
Each of the G protein molecules has an active site that can to the head of a myosin molecule. There are about 50 molecules of tropomyosin in each thin filament . When the muscle fiber is relaxed these tropomyosin molecules block the active sites for myosin binding to thin filaments . Also in thin filaments is a calcium binding molecule , that is, troponin.
