Question

507 What is the role of Ubiquitin Ligases during the cell cycle?

1) Initiation of DNA replication
2) Separation of sister chromatids
3) Degradation of cyclins
4) Formation of the mitotic spindle

Answer 1

Ubiquitin Ligases are crucial for timely regulation of the cell cycle, primarily through the degradation of cyclins, which allows orderly progression through cell cycle stages.

Step-by-step explanation:

The role of Ubiquitin Ligases during the cell cycle is to tag proteins, such as cyclins, with ubiquitin molecules, marking them for degradation by the proteasome. This process ensures the timely regulation of the cell cycle by removing proteins that are no longer needed, thus preventing the premature advancement or delay of the cell cycle. Specifically, ubiquitin ligases are involved in the degradation of cyclins after their role in advancing the cell through different checkpoints has been fulfilled.