Vertebrate smooth muscle cells are activated when Ca⁺ binds to:

Question

Quizplus · Accepted Answer

When Ca2+ binds to calmodulin, it activates myosin light chain kinase (MLCK), which in turn phosphorylates myosin regulatory light chains, leading to smooth muscle contraction. Therefore, choice A (calmodulin) is the correct answer. Choices B (troponin) and C (tropomyosin) are involved in skeletal and cardiac muscle regulation, but not smooth muscle. Choice D (myosin kinase) is incorrect as it is actually activated by Ca2+-calmodulin, which is the target of the signaling pathway. Choice E (myosin) is incorrect as it is the effector molecule that generates the force in smooth muscle, but it is not directly activated by Ca2+.

Vertebrate Smooth Muscle Cells Are Activated When Ca+ Binds To

Vertebrate Smooth Muscle Cells Are Activated When Ca⁺ Binds To