Cell cycle checkpoints

Definition

Cell cycle checkpoints are control mechanisms in the cell cycle that ensure the proper progression of division. They prevent errors by halting the cycle until specific conditions are met.

5 Must Know Facts For Your Next Test

1. There are three main checkpoints: G1 checkpoint, G2 checkpoint, and M checkpoint.
2. The G1 checkpoint ensures that the cell has enough resources and is ready for DNA synthesis.
3. The G2 checkpoint verifies that DNA replication in S phase has been completed successfully before mitosis begins.
4. The M checkpoint, also known as the spindle checkpoint, ensures that all chromosomes are properly aligned and attached to the spindle fibers before anaphase proceeds.
5. Defects in cell cycle checkpoints can lead to uncontrolled cell division, which is a hallmark of cancer.

Review Questions

• What are the three main cell cycle checkpoints?
• Why is the G2 checkpoint important for cell division?
• How does the M checkpoint contribute to genetic stability during mitosis?

Related terms

Mitosis: The process of cell division where one cell splits into two genetically identical daughter cells.

Apoptosis: Programmed cell death that helps eliminate damaged or unnecessary cells.

Cyclins: Regulatory proteins whose levels fluctuate throughout the cell cycle to control progression through various phases.