Relate Cancer to Loss Of Regulation
Write a short claim-evidence-reasoning paragraph from a small set of data.
- Read a data table: Students need to find values, labels, and units before calculating or graphing.
- Fair-test logic: Variables and controls make comparisons meaningful.
Prerequisites are inferred: pending teacher review.
Re-learn the skill with worked practice and clear examples.
Re-learn how a tumor-suppressor (like TP53/p53) loss removes the STOP signal and lets cells divide without control, and tell a proto-oncogene from a tumor-suppressor.
| Gene type | Normal job | What a harmful change does |
|---|---|---|
| Proto-oncogene | Sends a GO signal to divide | Mutation makes it an oncogene stuck ON (too much go) |
| Tumor-suppressor (e.g. TP53) | Sends a STOP signal at the checkpoint | Loss removes the brake, so division is not stopped |
Use the table. TP53 makes the p53 protein, which sends a STOP signal at the cell-cycle checkpoint. A cell has a mutation that makes its TP53 stop working. What is the most likely result for that cell?
Reviewed| Gene type | Normal job | What a harmful change does |
|---|---|---|
| Proto-oncogene | Sends a GO signal to divide | Mutation makes it an oncogene stuck ON (too much go) |
| Tumor-suppressor (e.g. TP53) | Sends a STOP signal at the checkpoint | Loss removes the brake, so division is not stopped |
- A.It loses the STOP signal, so it keeps dividing without control
- B.It divides one time and then dies on schedule
- C.It turns into a red blood cell
- D.It sends a stronger STOP signal than before
Show the worked solution ▾
Answer: A. It loses the STOP signal, so it keeps dividing without control
- Step 1: Find TP53 in the table: The table lists TP53 as a tumor-suppressor whose job is the STOP signal.
- Step 2: Apply the loss: If TP53 stops working, the STOP signal is lost.
- Step 3: Predict the result: With no STOP at the checkpoint, the cell keeps dividing without control.
Why it's right: Losing a working tumor-suppressor removes the STOP signal at the checkpoint, so division is no longer held back.
- B: Losing the brake leads to more division, not a normal single division then death.
- C: Losing a tumor-suppressor does not change a cell into a red blood cell.
- D: A broken TP53 makes a weaker or absent STOP signal, not a stronger one.
Aligned to Biotechnology Research and Experiments · reading level ~grade 9
- In Unit 3.1 Detecting Cancer, students explain how losing p53 control lets cells divide without a stop signal.
Fill these in as you work through the lesson.
- Cell-cycle checkpoint (where the cell stops and checks before dividing):
- Tumor-suppressor gene (a STOP gene, e.g. TP53/p53):
- Proto-oncogene (a GO gene that tells a cell to divide):
- Loss of regulation (the controls fail, so division does not stop):
A working gene like TP53 sends a signal at the checkpoint; if it is lost, the cell divides control and a tumor can form.
- What does a checkpoint do in the cell cycle?
- How is a proto-oncogene different from a tumor-suppressor gene?
- Why does losing p53 lead to uncontrolled division?
A tumor has a broken TP53. Claim: it grew from loss of regulation. Evidence: TP53 mutation, cells divide past the checkpoint. Reasoning: with no STOP signal, the checkpoint fails and cells divide without control.