AP BIOLOGY

Detailed explanation-1: -The cell cycle is regulated by many cyclins and cyclin-dependent kinases (CDKs) that are a group of serine/threonine kinases. They form complexes with cyclins to stabilize, activate, and phosphorylate CDKs in the specific phases [6, 7].

Detailed explanation-2: -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-3: -Cyclins are the regulatory subunits of holoenzyme CDK complexes that control progression through cell-cycle checkpoints by phosphorylating and inactivating target substrates. The cyclins associate with different CDKs to provide specificity of function at different times during the cell cycle (see Fig.

Detailed explanation-4: -Cyclins are regulatory proteins involved in the cell cycle that have no enzymatic function, while cyclin dependent kinases are catalytic proteins involved in the cell cycle that have an enzymatic function. So, this is the key difference between cyclins and cyclin dependent kinases.