AP BIOLOGY

Detailed explanation-1: -Summary. Cyclin-dependent kinases (CDKs) are protein kinases characterized by needing a separate subunit-a cyclin-that provides domains essential for enzymatic activity. CDKs play important roles in the control of cell division and modulate transcription in response to several extra-and intracellular cues.

Detailed explanation-2: -Two groups of proteins, called cyclins and cyclin-dependent kinases (Cdks), are responsible for the progress of the cell through the various checkpoints. The levels of the four cyclin proteins fluctuate throughout the cell cycle in a predictable pattern (Figure 2).

Detailed explanation-3: -Cyclin-dependent kinases In order to drive the cell cycle forward, a cyclin must activate or inactivate many target proteins inside of the cell. Cyclins drive the events of the cell cycle by partnering with a family of enzymes called the cyclin-dependent kinases (Cdks).

Detailed explanation-4: -The CDKs directly involved in the regulation of the cell cycle associate with small, 9-to 13-kiloDalton proteins called Suk1 or Cks. These proteins are required for CDK function, but their precise role is unknown. Cks1 binds the carboxy lobe of the CDK, and recognizes phosphorylated residues.