ENADE Ciências Biológicas Practice Questions - ENADE Ciências Biológicas - Bacharelado And Licenciatura Exam

Access More Questions

The eukaryotic cell cycle is tightly controlled by cyclin-dependent kinases (CDKs) and their regulatory cyclin subunits. What molecular event is required for a mammalian cell to pass the G1/S restriction point (R-point) and commit to DNA replication?

Hyperphosphorylation of the Retinoblastoma protein (pRb) by Cyclin D-CDK4/6 and Cyclin E-CDK2 complexes, releasing active E2F to transcribe S-phase genes. Dephosphorylation of the Retinoblastoma protein (pRb) by protein phosphatase 1, which locks the E2F transcription factor in a repressive complex. Proteasomal degradation of the Anaphase-Promoting Complex/Cyclosome (APC/C) triggered by high levels of Cyclin B1. Direct ubiquitin-mediated destruction of DNA polymerase delta and single-stranded DNA binding protein RPA by the p53 tumor suppressor.

Correct Answer:

Hyperphosphorylation of the Retinoblastoma protein (pRb) by Cyclin D-CDK4/6 and Cyclin E-CDK2 complexes, releasing active E2F to transcribe S-phase genes.

Access more questions from this quiz

Continue to ENADE Ciências Biológicas Practice Questions - ENADE Ciências Biológicas - Bacharelado and Licenciatura Exam for more practice questions and the full quiz experience.

Access More Questions