Biology / Unit 4 Bio 0877 short lesson, about 20 seconds
Cell-Cycle Checkpoints, Three Gates
Captions available
The idea
A cell-cycle checkpoint is an internal control point halting progress until required conditions are met, with major checkpoints at the end of G1, at the G2-to-mitosis transition, and during metaphase.
In practice
A cell with unrepaired DNA damage can be held indefinitely at one checkpoint rather than proceeding.
Where people slip
These checkpoints are internal gates, distinct from the external growth-factor signals that trigger the cycle.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
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