Biology / Unit 4 Bio 0885 short lesson, about 20 seconds
Cyclins and Cyclin-Dependent Kinases
Captions available
The idea
Cyclins and cyclin-dependent kinases, or Cdks, are the cell cycle's positive regulators; cyclin levels rise and fall predictably, and only a cyclin-bound, phosphorylated Cdk pushes the cell past a checkpoint.
In practice
A cyclin's concentration peaks shortly before its checkpoint, then drops sharply as it is degraded.
Where people slip
Cdk levels stay roughly constant — cyclin concentration's rise and fall times each transition.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
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