Regulating The Cell Cycle
Not all cells divide! Muscle cells and nerve cells do not divide once they are developed
Some cells divide frequently Skin, digestive lining, blood cells
How does a cell know if it should divide? Contact: when cells come into contact with one another they stop dividing Density: when cells are too crowed, they stop dividing
Cyclins: -proteins that regulate cell cycle in eukaryotic cells High cyclin = cell division Low cyclin = no cell division
Cyclins: Messages from within the cell: internal regulators Messages from outside cell: external regulators Both control the production of cyclin
Cancer: Uncontrolled Growth Cancer cells ignore normal cell signals and divide constantly form masses = tumors can damage surrounding tissues
Cancer: Uncontrolled Growth Causes of cancer can be different: smoking tobacco, radiation exposure, chemical exposure, viral infections
Cancer: Uncontrolled Growth All cancers have 1 thing in common: The control over the cell cycle has broken down!!