You have designed a drug that is supposed to bind to the myosin binding sites on actin.You inject it into a relaxed muscle,but find that none of the drug bound.Which of the following explains why?
A)There are no myosin binding sites on actin.
B)Troponin molecules are covering myosin binding sites on actin.
C)The myosin binding sites are covered by ATP.
D)The myosin binding sites on actin are covered by tropomyosin.
E)None of the choices are correct.

Question

Quizplus · Accepted Answer

The myosin binding sites on actin are covered by tropomyosin in relaxed muscle. This prevents myosin heads from binding and initiating muscle contraction. Therefore, the drug that is designed to bind to the myosin binding sites on actin will not bind if these sites are covered by tropomyosin.

You Have Designed a Drug That Is Supposed to Bind