When a sarcomere is at rest, the myosin binding sites on actin are blocked by
A) calcium.
B) troponin.
C) tropomyosin.
D) the myosin heads.
E) ADP.

Question

Quizplus · Accepted Answer

Tropomyosin is a protein that blocks the myosin binding sites on actin when the sarcomere is at rest. Calcium and troponin are involved in the process of muscle contraction, and the myosin heads and ADP are not involved in blocking the myosin binding sites on actin.

When a Sarcomere Is at Rest, the Myosin Binding Sites