Final answer:
The cell-cycle control system delays progress through the cycle primarily by the inhibition of cyclin-dependent kinases (Cdks) through the action of Cdk inhibitors. so, option 2 is the correct answer.
Step-by-step explanation:
The cell-cycle control system uses several methods to regulate the progress of the cell through its cycle. One of the primary methods for delaying progression is the inhibition of cyclin-dependent kinases (Cdks). Cdks, when fully activated, phosphorylate other proteins that advance the cell cycle past checkpoints. However, Cdk inhibitors can block the full activation of Cdks, preventing the cell cycle from proceeding until certain conditions are met. These inhibitor molecules work by directly or indirectly monitoring particular cell-cycle events, ensuring that the cell only advances once it is ready.
The cell-cycle control system uses inhibition of cyclin-dependent kinases (Cdks) to delay progress through the cycle.
The cell-cycle control system uses inhibition of cyclin-dependent kinases (Cdks) to delay progress through the cycle. Molecules that prevent the full activation of Cdks are called Cdk inhibitors. These inhibitors essentially block the progression of the cell cycle until specific events are completed.