Images removed due to copyright considerations. See the following: Figure 1 and Table 1 in Reed SI. 2003. Ratchets and clocks: The cell cycle nover 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
Muscle cells But if in the same organIsm, should have the same DNA per Nerve cells( cell Different cells have different clusters of genes active Development and differentiation of embryos is controlled by signaling molecules that alter gene expression in cells