At Several Points in the Cell Cycle There Are Checkpoints

question 69

Essay

At several points in the cell cycle there are checkpoints that control the cell's passage from one phase to the next. If a cell receives a signal at each checkpoint, it continues to the next phase; if it does not receive the signal, the cell does not continue. For example, a growth factor may stimulate a cell to move from G₁ into S phase. If no growth factor is present, the cell cycle stops in G₁ and the cell does not divide. Predict what would happen to a cell and to a multicellular organism if there was a defect at the checkpoint and the cell continued through the cell cycle even in the absence of a signal.

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