What does Target theory state about a cell dying after radiation exposure?

What does Target theory state about a cell dying after radiation exposure?

• A. The master target molecule (DNA) must be inactivated
• B. The entire nucleus must be destroyed
• C. All proteins must be damaged
• D. The cytoplasm must be disrupted

Answer: (A)

Target theory holds that a cell dies when its essential genetic target—the DNA—loses function. DNA carries the instructions for replication and survival, so when enough damage inactivates this master target, the cell can no longer carry out critical processes and ultimately cannot reproduce, leading to death. Damage to other parts, like the cytoplasm or proteins, can occur, but they don’t determine lethality on their own unless they also compromise DNA repair or the vital genetic information. That’s why the idea that the master target molecule, DNA, must be inactivated best explains radiation-induced cell death.

Target theory holds that a cell dies when its essential genetic target—the DNA—loses function. DNA carries the instructions for replication and survival, so when enough damage inactivates this master target, the cell can no longer carry out critical processes and ultimately cannot reproduce, leading to death. Damage to other parts, like the cytoplasm or proteins, can occur, but they don’t determine lethality on their own unless they also compromise DNA repair or the vital genetic information. That’s why the idea that the master target molecule, DNA, must be inactivated best explains radiation-induced cell death.