Question

MPF activity was found to be oscillate during the cell cycle, although the amount of its kinase

component, called _______, remained constant.

Answer 1

The stable kinase component of MPF activity during the cell cycle is cyclin-dependent kinase (cdk), while the fluctuating levels of cyclin regulate MPF activity.

Step-by-step explanation:

The kinase component of MPF activity that remained constant throughout the cell cycle is called cyclin-dependent kinase (cdk). Although cdk levels remain stable, MPF's activity fluctuates because it is regulated by the concentration of cyclin. Cyclin levels vary, peaking during the transition from G2 into mitosis, and declining thereafter. Without cyclin, the cdk does not lead to active MPF, as both subunits are required for full kinase activity. It is the oscillation of cyclin concentration, not cdk, that leads to the fluctuating activity of MPF during the cell cycle.