cell division cycle

• What is the primary outcome of the cell cycle?

  Formation of two identical daughter cells
• What regulates the cell cycle?

  Cyclin-dependent kinases and cyclins
• What is the role of checkpoints in the cell cycle?

  Ensure DNA integrity before cell division
• What can disruptions in the cell cycle lead to?

  Cancer
• What are the main phases of the cell cycle?

  • Interphase
  • M Phase (Mitotic Phase)
• What occurs during Interphase?

  1. G1 Phase: Cell growth and preparation for DNA replication
  2. S Phase: DNA replication
  3. G2 Phase: Final preparation for mitosis
• What happens during the G1 Phase?

  Cell grows and prepares for DNA replication
• What is the G0 phase?

  Inactive state where cells exit the cycle
• What occurs during the S Phase?

  DNA replication occurs
• What is the purpose of the G2 Phase?

  Final preparation for mitosis
• What is Mitosis?

  Division of the nucleus and segregation of chromosomes
• What is Cytokinesis?

  Division of the cytoplasm to form two cells
• How is the cell cycle regulated?

  • Cyclin-Dependent Kinases (Cdks)
  • Cyclins
  • Checkpoints
• What do Cyclin-Dependent Kinases (Cdks) do?

  Transfer phosphate groups from ATP to proteins
• How are Cdks activated?

  By binding to Cyclins
• What happens to cyclin concentrations during interphase?

  They rise
• What happens to cyclin concentrations during M phase?

  They drop
• What are the roles of different Cyclin-Cdk complexes?

  • G1-Cdk: Triggers progression through G1 phase
  • G1/S-Cdk: Prepares for DNA replication
  • S-Cdk: Initiates DNA replication
  • M-Cdk: Triggers mitosis
• What is the role of G1-Cdk?

  Triggers progression through G1 phase
• What is the role of G1/S-Cdk?

  Prepares the cell for DNA replication
• What is the role of S-Cdk?

  Initiates DNA replication during S phase
• What is the role of M-Cdk?

  Triggers mitosis and chromosome condensation
• What are the regulation mechanisms of the cell cycle?

  • Phosphorylation & Dephosphorylation
  • Cyclin Degradation
  • Positive Feedback
• How are Cdks activated or inactivated?

  By adding or removing phosphate groups
• What marks cyclins for degradation?

  Ubiquitylation
• What is positive feedback in the context of Cdks?

  Activated Cdks enhance their own activation
• What is the role of checkpoints in the cell cycle?

  • Ensure undamaged DNA is replicated
  • Prevent segregation of damaged DNA
• What does the p53 protein do when activated?

  Induces transcription of p21
• What is the function of p21?

  Binds to Cdks, causing cell cycle arrest
• What is a model organism used for studying the cell cycle?

  Xenopus laevis
• Why are Xenopus laevis eggs useful for studying the cell cycle?

  They have rapid cell cycling
• What can M phase extracts induce in Xenopus oocytes?

  Induce M phase
• How can mutations in cyclins and Cdks lead to cancer?

  • Cause uncontrolled cell division
  • Lead to tumor formation
• What are some oncogenic changes associated with Cyclin D1?

  • Overexpression
  • Gene amplification
• What tumors are associated with Cyclin D1?

  • Breast carcinoma
  • B-cell lymphoma
  • NSCLC
  • Bladder carcinoma
• What are some oncogenic changes associated with Cyclin E?

  • Overexpression
  • Gene amplification
• What tumors are associated with Cyclin E?

  • Colorectal carcinoma
  • Breast carcinoma
  • Prostate carcinoma
  • Ovarian carcinoma
• What are some oncogenic changes associated with Cyclin B1?

  • Overexpression
• What tumors are associated with Cyclin B1?

  Colorectal carcinoma
• What are some oncogenic changes associated with CDK2?

  • Overexpression