8 Questions
What is the primary assumption of the target theory?
Radiation damage to sensitive molecules can cause cell death
What is the target molecule in the target theory?
DNA
What is the consequence of radiation damage to abundant molecules?
No noticeable injury to the cell
What is the characteristic of the target molecule in the target theory?
Low abundance
What is the outcome of radiation interaction with the target molecule?
A hit, which can occur through both direct and indirect effects
What is the reason for the sensitivity of the target molecule to radiation?
Its vital function in the cell
What is the concept of the target in the target theory?
An area of the cell occupied by the target molecule or a sensitive site
What is the original application of the target theory?
To describe cell lethality
Study Notes
Target Theory
- Cells contain many species of molecules, most of which exist in excess, making them less susceptible to radiation damage.
- However, some molecules are essential for normal cell function and are present in limited quantities, making them vulnerable to radiation damage.
- Radiation damage to these critical molecules can severely affect the cell because there are no substitutes available.
- The target theory is based on the concept of a sensitive key molecule that must be inactivated for a cell to die after radiation exposure.
- DNA is considered the target molecule.
Target Molecule
- The target molecule is an area of the cell occupied by the molecule or a sensitive site on the molecule.
- The target area changes position over time due to intracellular molecular movement.
- The interaction between radiation and cellular components is random, with no preference for the target molecule.
Radiation Interaction
- When radiation interacts with the target molecule, it is considered a "hit."
- Radiation can also interact with molecules other than the target molecule, resulting in indirect effects.
- It is not possible to distinguish between direct and indirect hits.
- Hits occur through both direct and indirect effects of radiation.
This quiz covers the effects of radiation damage on cell molecules, including the abundance of molecules and the impact on cell function.
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