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ch 34 radiobioloby
chapter 34 radiobioloby
Question | Answer |
---|---|
In vitro | Outside the body or outside the cell |
Cytogenetic damage | Radiation-induced structural change in chromosomes |
Point mutation | Radiation damage that consists of a molecular lesion of the DNA and causes genetic mutation |
Free radical | A short-lived, highly reactive, uncharged molecule containing a single unpaired electron in the outermost shell |
Target theory | The radiobiologic theory that says for a cell to die, after radiation exposure, its target molecule must be inactivated |
D37 | The dose that kills 63% of the cells after the single-hit single target model |
Mean lethal dose | Analogous to D37 and the single-hit single target model. D0 refers to the single-hit multitarget model. |
Radiation hit | Occurs when a radiation interaction occurs with the target |
Extra-population number | Sometimes called target number |
DQ | Threshold dose |
Effects of irradiation of macromolecules in solution in vitro | Main chain scission, cross-linking, point mutations, change in viscosity |
How solution viscosity used to determine the degree of radiation macromolecular damage | Viscosity drops after a high dose of radiation of macromolecules. It is a measure of the degree of main-chain scission of macromolecules. |
Difference between catabolism and anabolism | Catabolism is the destruction of large molecules into smaller molecules. Anabolism is the construction of large molecules from smaller molecules. |
The phase of the cell cycle when the DNA ladder opens up in the middle of each rung and consists of only one single chain | Synthesis (S) phase |
The three principle observable effects of DNA irradiation | Cell death, malignant disease and genetic damage |
The difference between transcription, transfer, and translation when applied to molecular genetics | Transcription = read the DNA code. Transfer the code to anabolic molecules. Translate the code into new molecule. |
Formula for radiolysis of water in which the atom of water is ionized and dissociated into two ions | H2O + Energy in the form of radiation HOH+ + e− |
This happens to radiation-induced free radicals with in the cell | They migrate within the cell, transferring energy to target molecules, and ultimately join with another molecule to be neutralized. |
The target theory of radiobiology | That each cell contains a target site(s) on a target molecule, which must be hit in order to cause cell death |
Does radiation interact with tissue uniformly or randomly | Radiation exposure of tissue is rather uniform because tissue is large on the x-ray scale. However, radiation interaction with target molecules is random. |
The difference between in vitro and in vivo | In vitro refers to irradiation that occurs outside the body or outside the cell; in vivo irradiation is irradiation of macromolecules in the living cell. |
H20 + radiation | = HOH+ + e− |
HOH+ (dissociation) | = H+ + OH* |
HOH- (dissociation) | = OH− + H* |
Difference between direct effect and indirect effect | A direct effect exists when the ionizing radiation interacts directly with the target molecule DNA. An indirect effect occurs when the interactions is with some other molecule, resulting in free radical formation, which then transfers this energy to DNA. |
How the radiosentivity of human cells vary with stages of the cell cycle | Most sensitive during M; least sensitive during last S |