Question

Calcium receptive protein of muscles is

• A. Myosin
• B. Actin
• C. Tropomyosin
• D. Troponin

Answer 1

The correct option is D Troponin

Thin filament of the sarcomere is made up of actin, troponin and tropomyosin. Muscle contraction can happen when myosin head of thick filament binds to the myosin binding site of thin filament. But, this site is covered by troponin-tropomyosin complex. Upon stimulation of muscle by an neural impulse, calcium is released from sarcoplasmic reticulum which binds to troponin and brings about a change in the confirmation of tropomyosin. This exposes the myosin binding site of thin filament and causes binding and contraction.