Which of the following statements about myosin is correct?

• A. Myosin is a protein that forms the thin filaments in muscle fibers.
• B. Myosin is primarily found in the sarcoplasmic reticulum of muscle cells.
• C. Myosin is responsible for the passive elasticity of muscle tissue.
• D. Myosin is a motor protein that interacts with actin to cause muscle contraction.

Answer: (D)

Verified step by step guidance

1. Understand the role of myosin in muscle contraction: Myosin is a motor protein that plays a crucial role in muscle contraction by interacting with actin filaments.
2. Differentiate between thin and thick filaments: In muscle fibers, myosin forms the thick filaments, while actin forms the thin filaments.
3. Identify the location of myosin: Myosin is primarily located in the myofibrils of muscle cells, not in the sarcoplasmic reticulum.
4. Clarify the function of myosin: Myosin is not responsible for passive elasticity; it actively interacts with actin to facilitate muscle contraction through the sliding filament theory.
5. Recognize the correct statement: The correct statement is that myosin is a motor protein that interacts with actin to cause muscle contraction, distinguishing it from the other incorrect options.