Which of the following causes a muscle cell to contract?

Question

Quizplus · Accepted Answer

The myosin heads attached to actin bend, resulting in a sliding of the actin filaments towards the center of the sarcomere, leading to muscle contraction. This process is powered by ATP hydrolysis. Choice A is incorrect because breakdown of actin and myosin would not result in muscle contraction. Choice B is incorrect because actin heads do not attach to myosin; instead, myosin heads attach to actin. Choice C is incorrect because although calcium ions are necessary for muscle contraction, they do not directly form a bridge binding actin to myosin. Choice D is incorrect because ATP does not directly form a bridge binding actin to myosin, but rather it provides the energy for myosin to bind and bend.

Which of the Following Causes a Muscle Cell to Contract