Question

multiple choice question

which protein makes up the thick filaments of a myofibril?

troponin
myosin
actin
tropomyosin

Explanation:

Identify the components of myofibrils

Using the Myofibrils knowledge point, we recall that myofibrils are composed of two main types of protein filaments: thick filaments and thin filaments.

Analyze thick filament composition

Thick filaments are primarily composed of the motor protein myosin. Each myosin molecule has a tail and two globular heads that bind to actin during muscle contraction.

Analyze thin filament composition

Thin filaments are primarily composed of the protein actin, along with regulatory proteins called tropomyosin and troponin.

Evaluate the given options

• Troponin: Part of the thin filament.
• Myosin: The primary protein making up the thick filament.
• Actin: The primary protein making up the thin filament.
• Tropomyosin: Part of the thin filament.

Therefore, the protein that makes up the thick filaments is myosin.

Answer:

• Troponin
• Myosin (Correct answer)
• Actin
• Tropomyosin