Question

In the resting muscle fibre, tropomyosin partially covers

• A. calcium binding sites on troponin
• B. actin binding sites on myosin
• C. myosin binding sites on actin
• D. calcium binding sites on actin.

Answer 1

The correct option is C myosin binding sites on actin

Tropomyosin is a protein found in the actin filaments in muscles. The molecule contains two elongated strands that run along the length of the filament. When the muscle is at rest, the tropomyosin molecule covers the binding site of the actin molecule, where interaction with myosin occurs, On contraction of the muscle, the tropomyosin is displaced by another protein, troponin, allowing the interaction of actin with myosin. So, the correct answer is (c).