The Cyclin Component of MPF is Destroyed Toward the End

Question

The cyclin component of MPF is destroyed toward the end of which phase?
A)G₀
B)G₁
C)S
D)G₂
E)M

Accepted Answer

The cyclin component of MPF is destroyed during the exit from mitosis, in the M phase. This destruction is triggered by the activation of a ubiquitin ligase called the anaphase-promoting complex (APC). Once the cyclin is destroyed, the kinase component of MPF (CDK) is inactive, causing the cell to exit mitosis and enter G1 phase.