PATHOLOGY

Detailed explanation-1: -The central components of the cell-cycle control system are cyclin-dependent protein kinases (Cdks), whose activity depends on association with regulatory subunits called cyclins. Oscillations in the activities of various cyclin-Cdk complexes leads to the initiation of various cell-cycle events.

Detailed explanation-2: -Two groups of proteins, cyclins and cyclin-dependent kinases (Cdks), are responsible for promoting the cell cycle.

Detailed explanation-3: -Cyclins drive the events of the cell cycle by partnering with a family of enzymes called the cyclin-dependent kinases (Cdks). A lone Cdk is inactive, but the binding of a cyclin activates it, making it a functional enzyme and allowing it to modify target proteins.

Detailed explanation-4: -Cyclins are a family of proteins that regulate the timing of the cell cycle in eukaryotic cells. Internal regulators-proteins that respond to events inside a cell. External regulators-proteins that respond to events outside the cell.-speed up or slow down the cell cycle.