Cyclin dependent kinases (Cdk) are proteins that work with cyclin regulatory proteins. The cyclins are associated with different checkpoints of the cell cycle. Different phases of the cell cycle experience activation and/or deactivation of specific cyclin-Cdk complexes. CyclinB-CDK1 activity is specific to the G2/M checkpoint. Referring to the graph, what is the relationship between the concentration of cyclin B and Cdk1 activity?
A) From the graph given, cyclin B is not needed to increase activity of Cdk1.
B) As the concentration of cyclin B increases, the activity of Cdk1 is deactivated.
C) When Cdk1 activity decreases, cyclin B remains constant through the G2 phase at all times.
D) When the concentration of cyclin B increases it binds to Cdk1 and increases activity to enter the cell into the mitotic stage.