Introductory slides for Session 6 mages removed due to copyright considerations. See the following Figure 1 and Table 1 in Reed Sl. 2003. Ratchets and clocks: The cell cycl ubiquitylation and protein turnover. Nat. Rev. Mol. Cell BioL. 4: 855-864 Figure 1 in Bartek J, Lukas J Mammalian G1-and S-phase checkpoints in response to DNA damage. Curr Opin Cell Biol. 2001 Dec; 13(6): 738-47.Introductory slides for Session 6 Images removed due to copyright considerations. See the following: Figure 1 and Table 1 in Reed SI. 2003. Ratchets and clocks: The cell cycle, ubiquitylation and protein turnover. Nat. Rev. Mol. Cell Biol. 4: 855-864. Figure 1 in Bartek J, Lukas J. Mammalian G1- and S-phase checkpoints in response to DNA damage. Curr Opin Cell Biol. 2001 Dec;13(6):738-47