Chapter 12 Lecture notes

Chapter 12 Lecture notes

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Unformatted text preview: es events in the cell cycle Analogy is the control devise of an automa+c washing machine •  •  Control system proceeds on its own  ­ driven by a built ­in clock •  System is subject to various internal and external regula+ons at various checkpoints •  Checkpoint: •  Animals usually have built ­in stop signals that halt cell cycle at check points un+l they are overridden by a go ­ahead signal Key quesAons are asked at each checkpoint: Stop Signal: Stop Signal: Stop signal: Is all DNA replicated? The G1 Checkpoint: “RestricAon Point” in mammalian cells •  Most important checkpoint in mammalian cells •  If cell receives go ­ahead signal, it will enter G1, S, G2, M, and divide •  If cell does not receive the go ­ahead signal, it will exit the cycle and switch to a nondividing state call G0 phase •  •  Liver cells can be “called back” from G0 phase to the cell cycle by external cues (e.g. growth factors released during a wound injury) The Cell Cycle Clock: Two types of regulator molecules control the pace of the cycle 1.  Protein Kinases: enzymes t...
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This document was uploaded on 02/10/2014.

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