Chapter 28, Problem 19P

Figure 28.11 depicts the eukaryotic cell cycle. Many cell types “exit� the cell cycle and don’t divide for prolonged periods, a state termed ${\text{G}}_0$; some, for example neurons, never divide again.

a. In what stage of the cell cycle do you suppose a cell might be when it exits the cell cycle and enters ${\text{G}}_0$?

b. The cell cycle is controlled by checkpoints, cyclins, and CDKs. Describe how biochemical events involving cyclins and CDKs might control passage of a dividing cell through the cell cycle.