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Cell & Molecular Biology
Cell-cycle control
Use this for “Put G1, S, G2 and M in order, and name the checkpoint that ends each.”
Put in order
Put the phases in order, from G1, with the checkpoint that ends each.
1
?
2
?
3
?
4
?
Assumptions
•
The times are for a typical human cell dividing in culture, 24 h a cycle.
•
A cyclin switches on its CDK and is then destroyed, so each phase is driven by its own cyclin.
•
A cell that fails a checkpoint stops to repair, or p53 sends it into lasting arrest or apoptosis.
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