Mutations in the gene for troponin can result in the production of the troponin protein, which has varying affinities for Ca2+ ions. Suppose that in a muscle cell a mutant troponin is expressed that has such a high affinity for Ca2+ ions that once they bind to troponin they cannot unbind. What will likely happen in this muscle cell?
A) Myosin heads will not bind to actin after action potentials stop being received.
B) Myosin heads will bind to actin after action potentials stop being received.
C) Tropomyosin will not move to expose myosin binding sites.
D) Cross-bridges will form between myosin and tropomyosin.

Question

Quizplus · Accepted Answer

Troponin's binding to Ca2+ ions is a key step in muscle contraction, as it leads to the movement of tropomyosin away from myosin-binding sites on actin, allowing myosin heads to bind to actin. If troponin cannot release Ca2+ ions, it will perpetually signal for muscle contraction, meaning myosin heads will continue to bind to actin even after action potentials stop.

Mutations in the Gene for Troponin Can Result in the Production