7. Cyclins.
8. Cyclin-dependent kinases.
9. Cyclin/CDK.
10. Checkpoints.
11. G1 Stage.
12. S Stage.
13. G2 Stage.
14. Mitosis.
15. Cytokinesis.
Each stage of the cell cycle has related cyclins that help the progression of that phase. Cyclins bind to cyclin-dependent kinases and activate them. The kinases are therefore able to phosphorylate particular protein and activate or deactivate them appropriately to progress the particular cell cycle stage. P53 tumor suppressor protein proteins help regulate this progress at each checkpoint. They do so by activating CDK inhibitors when required (such as when there is damage to the cells DNA).
