MICROANATOMY

Detailed explanation-1: -Tropomyosin is a fibrous protein that binds lengthwise along the groove of actin filaments . In striated muscle, each tropomyosin molecule is bound to troponin, which is a complex of three polypeptides: troponin C (Ca2+-binding), troponin I (inhibitory), and troponin T (tropomyosin-binding).

Detailed explanation-2: -Tropomyosin is a protein that winds around the chains of the actin filament and covers the myosin-binding sites to prevent actin from binding to myosin.

Detailed explanation-3: -Tropomyosin covers the actin binding sites, preventing myosin from forming cross-bridges while in a resting state.

Detailed explanation-4: -Calcium is required by two proteins, troponin and tropomyosin, that regulate muscle contraction by blocking the binding of myosin to filamentous actin. In a resting sarcomere, tropomyosin blocks the binding of myosin to actin.