Question

when things go wrong: cell cycle & cancer
analyzing disruptions: use the words from the word back to complete the questions below.
word bank: uncontrollable, apoptosis, continuously, tumor, mutation, cancer
scenario 1: a cells dna is damaged, but the g1 checkpoint works correctly. what happens to this cell? complete the sentence.
the checkpoint works; the cell will

scenario 2: a cell has a mutation in a gene for the g2 checkpoint. what might happen when this cell divides? complete the sentence.
if the g2 checkpoint fails, the cell might

scenario 3: a cell begins to ignore signs that tell it to stop dividing. how does this relate to cancer?

cause & effect: from disruption to disease
cause: uv radiation damages a cells dna.
effect: the cell cycle should at the g1 checkpoint. (stop, speed up)
cause: the checkpoint gene is mutated and fails.
effect: the damaged cell will then

Explanation:

• Scenario 1: When the G1 checkpoint works correctly and DNA is damaged, the cell undergoes apoptosis (programmed cell death) to prevent faulty cell division.
• Scenario 2: If the G2 checkpoint fails (due to mutation), the cell might divide uncontrollably as it skips checking for DNA damage post - replication.
• Scenario 3: Cells that ignore stop - dividing signals can form a tumor. If the tumor is malignant (cancerous), it can invade other tissues.
• Cause & Effect (UV Radiation): UV - damaged DNA should make the cell cycle stop at G1 (as a protective mechanism).
• Cause & Effect (Checkpoint Gene Mutation): A mutated checkpoint gene that fails allows the damaged cell to divide continuously.

Answer:

• Scenario 1: The checkpoint works; the cell will apoptosis.
• Scenario 2: If the G2 Checkpoint fails, the cell might divide uncontrollably.
• Scenario 3: This cell behavior can lead to the formation of a tumor, and if it progresses, it can be cancer (as cancer is characterized by uncontrolled cell growth).
• Cause & Effect (UV Radiation): The cell cycle should stop at the G1 Checkpoint.
• Cause & Effect (Checkpoint Gene Mutation): The damaged cell will then divide continuously.