4.7 Regulation of Cell Cycle

• Arrange the phases of the cell cycle in the correct order.

  1️⃣ G1

  2️⃣ S

  3️⃣ G2

  4️⃣ M
• The G1 checkpoint determines if the cell has grown large enough and if its DNA is undamaged.
• Match the cell cycle regulators with their roles:

  Cyclins ↔️ Activate CDKs

  Cyclin-Dependent Kinases (CDKs) ↔️ Phosphorylate target proteins

  Cyclin-CDK Complex ↔️ Regulates cell cycle transitions
• After mitosis, cells may enter a resting phase called G0.
• What is the resting phase after mitosis called?

  G0
• Match the checkpoint with its assessment:

  G1 Checkpoint ↔️ Cell size, nutrient availability, DNA damage

  G2 Checkpoint ↔️ DNA replication complete, no errors

  M Checkpoint ↔️ Chromosomes attached to spindle fibers
• What is the cell cycle defined as?

  Series of events for growth
• After the M phase, a cell can only repeat the cell cycle.

  False
• What does the M checkpoint confirm during metaphase?

  Chromosomes attached to fibers
• Growth factors stimulate cell division by binding to cell surface receptors.

  True
• What are the three major checkpoints in the cell cycle?

  G1, G2, and M checkpoints
• Key checkpoints in the cell cycle monitor essential conditions
• If conditions are not met at any checkpoint, the cell cycle halts until necessary adjustments are made.


  True
• What is the role of cyclins in the cell cycle?

  Activate CDKs
• Steps in how growth factors stimulate cell division:

  1️⃣ Growth factors bind to receptors on the cell surface

  2️⃣ Receptor activation triggers signal transduction

  3️⃣ Signaling pathways activate genes

  4️⃣ Cyclin-CDK complexes form

  5️⃣ Cell cycle progresses
• What are tumor suppressor proteins like p53 and Rb responsible for?

  Halting the cell cycle
• Dysregulation of negative regulators can lead to uncontrolled cell proliferation, a hallmark of cancer.


  True
• Proper cell cycle control is crucial for preventing uncontrolled cell proliferation seen in cancer
• Cyclins bind to CDKs to form a complex
• The cyclin-CDK complex promotes cell cycle transitions through phosphorylation
• Growth factors stimulate cell division by initiating intracellular signaling events.

  True
• Cyclin-dependent kinase inhibitors (CKIs) inactivate cyclin-CDK complexes
• Which negative regulator halts the cell cycle in response to DNA damage?

  Tumor suppressor proteins