key term - Cyclins

Definition

Cyclins are proteins that regulate the progression of the cell cycle by activating cyclin-dependent kinases (CDKs). They ensure that cell cycle events occur in the correct sequence and at the appropriate time.

5 Must Know Facts For Your Next Test

1. Cyclins bind to CDKs, forming a complex that drives the cell through specific stages of the cell cycle.
2. Different types of cyclins are active at different phases of the cell cycle (e.g., G1/S cyclins, S cyclins, M cyclins).
3. The levels of cyclins fluctuate throughout the cell cycle; they are synthesized and degraded as needed.
4. Cyclin-CDK complexes can be regulated by phosphorylation and dephosphorylation events.
5. Dysregulation of cyclin levels can lead to uncontrolled cell division and is often implicated in cancer.

Review Questions

Related terms

Cyclin-Dependent Kinases (CDKs): Enzymes that, when activated by binding to a cyclin, drive progression through various stages of the cell cycle.

Cell Cycle Checkpoints: Mechanisms that monitor and verify whether the processes at each phase of the cell cycle have been accurately completed before proceeding to the next phase.

Ubiquitin-Proteasome Pathway: A system responsible for degrading unneeded or damaged proteins, including cyclins, thus regulating their levels within cells.