Cell cycle regulation (cyclins, checkpoints) Knowledge-Based Download PDF

Questions

1. 1.

   Which of the following best explains how cyclin-dependent kinases (CDKs) are activated to regulate progression through cell cycle checkpoints?

   • A) Through periodic synthesis and rapid degradation of CDK proteins while cyclin levels remain constant
   • B) By binding to specific regulatory cyclins whose concentrations fluctuate periodically during the cell cycle
   • C) Through irreversible proteolytic cleavage of CDK monomers by proteasomes just prior to entry into mitosis
   • D) By direct binding of unattached kinetochore fibers to inactive CDK catalytic subunits