THE CELL
CELL COMMUNICATION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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It is completely degraded
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it is exported from the cell
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the cyclin component of MPF is degraded
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the Cdk component of MPF is degraded
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Detailed explanation-1: -The presence of MPF occurs when cyclin levels are high and CDKs are bound to those cyclins. However, once a cell advances into mitosis and through its stages (prophase, metaphase, anaphase, and telophase), the role of MPF slows. This occurs becaue the cyclin molecules steadily break down.
Detailed explanation-2: -For the cell to proceed through mitosis, MPF must be inactivated and other cyclins become active. This occurs through the destruction of cyclin M. During metaphase, MPF activates another protein complex called anaphase-promoting complex/cyclosome (APC/C).
Detailed explanation-3: -In addition to driving the events of M phase, MPF also triggers its own destruction by activating the anaphase-promoting complex/cyclosome (APC/C), a protein complex that causes M cyclins to be destroyed starting in anaphase.
Detailed explanation-4: -At the end of mitosis, degradation of mitotic cyclins results in the inactivation of cyclin-dependent kinases. Cyclin proteolysis is triggered by the anaphase-promot-ing complex/cyclosome (APC/C), a multi-subunit complex which contains ubiquitin ligase activity.
Detailed explanation-5: -if the cyclin could not be degraded, the MPF would always be active. therefore, the cell would be continuously pressured to move through the G2 checkpoint, even if the conditions were not right.