Amyosin molecule in the thick filaments can be considered a protein having a quaternary structural level. which of the following best describes this structural level?

1. myosin has an atp binding site, actin binding site and flexible hinge region.
2. myosin is involved in the power stroke of muscle contraction.
3. myosin molecules consist of two heavy and two light polypeptide chains.
4. myosin is a primary component within a myofibril.

Myosin molecules consist of two heavy and two light polypeptide chains. (Ans. C)

Explanation:

Myosin are present in both cells prokaryotic, and eukaryotic, it is present as a filaments inside the cells, and consist of two heavy, and two light polypeptide chains. It is function as a no. of interactions like contraction, and movements of muscles.

Myosin is known as a motor protein which helps to move the cell, and works with the globular protein, known as actin which polymerize to synthesize actin filaments. They are depends on ATP (a molecule that cells are using to work & live, into mechanical energy). Then this will generates movement, and forces.