Once a cell completes mitosis,molecular division triggers must be turned off.What happens to MPF during mitosis?
A)It is completely degraded.
B)The cyclin-dependent kinases take on a function unrelated to mitosis.
C)Cyclin is degraded;the concentration of cyclin-dependent kinase remains unchanged,but without cyclin,MPF is not formed.
D)Cyclin-dependent kinase is degraded;cyclin concentration remains constant,but without cyclin-dependent kinase,MPF is not formed.

Question

Quizplus · Accepted Answer

During mitosis, cyclin-dependent kinase (CDK) and cyclin form a complex called Mitosis Promoting Factor (MPF) which initiates mitosis. However, after mitosis is completed, cyclin is degraded, and the concentration of CDK remains constant; without cyclin, MPF is not formed. Therefore, choice C is the correct answer. Choice A is incorrect because MPF is not completely degraded; only cyclin is degraded. Choice B is incorrect because cyclin-dependent kinases are specifically associated with cell cycle control, including mitosis. Choice D is incorrect because CDK concentration remains constant; it is cyclin that is degraded.

Once a Cell Completes Mitosis,molecular Division Triggers Must Be Turned