🧬ap biology review

Cyclins

Written by the Fiveable Content Team • Last updated September 2025
Verified for the 2026 exam
Verified for the 2026 examWritten by the Fiveable Content Team • Last updated September 2025

Definition

Cyclins are proteins that regulate the progression of the cell cycle by binding to cyclin-dependent kinases (CDKs). They control when certain checkpoints occur during different phases of the cell cycle.