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RT 244 ch 31,32

Radio-biology chapters 31, 32, inverse square

QuestionAnswer
Regarding the radiosensitivity of macromolecules, the most radiosensitive is? DNA
Most cellular radiation damage resulting in a late total body effect and thought to be the site of radiation induced malignancies, is known as? Point lesions
The initial ionizing event produces two ions, they are? HOH+ and e-
The most common interaction of radiation and DNA is a result of what type of effect? Indirect effect
What does in vivo mean? within the living cell
Radiation effects occuring in vivo at the total body level occur mainly as a result of direct or indirect effect? Indirect
What does in vitro mean? outside the body, outside the cell
What is critical to the survival of the cell and its replication? Macromolecular sythesis of proteins, DNA, and RNA
The breakage of the thread or backbone is a long-chain macromolecule when irradiated in vitro is called? main-chain scission
What are the three principle observable effects resulting from irradiation of DNA in vivo? cell death, malignant diseases, and genetic damage
Regarding viscosity, after cross-linking occurs, describe the irradiated in vitro solution: there is a increase in viscosity
What is a reactive atom or molecule having an unpaired electron in its outer shell? free radical
When HOH+ dissociates into small molecules, what does it separate into? H+ and OH*
When HOH- dissociates into small molecules, what does it seperate into? OH- and H*
What are the free radicals produced during radiolysis of water? H* and OH*
2 hydroperoxyl free radicals join to form what? H202 (hydrogen peroxide)
An initial ionizing event occurs on a distant, non-critical molecule that transfers the energy of ionization to a target molecule, is this direct or indirect? Indirect
This radiation effect on a macromolecule has a sticky substance on the end that attaches to neighbors or to another segment of the same molecule, what effect is this? cross-linking
In what phase is the cell most sensitive? M phase
In what phase is the cell least sensitive? S phase
Regarding viscosity, when main-chain scission occurs in the solution,what happens to the irradiated in vitro solution? viscosity decreases
What is the irradiation of water that represents the principal interaction in the body? radiolysis
How long is the life of a free radical? less than 1 ms
What are the damaging products of radiolysis of water? hydrogen peroxide and hydroperoxyl
In terms of oxygen, radiation effects on human tissue are more effective if the cells are irradiated under what conditions? aerobic
The principal radiation interaction within the human body is with what? water
Radiation damage to DNA can result in? cell death, malignant diseases, genetic changes
A type of DNA damage that may not be reversible is what? base change or loss
After a low radiation dose, most cellular radiation damage that results in a late total-body effect occurs because of which of the following? Point lesions
The probability of human cell death can be computed by using what? Poisson distribution
The difference in generation time among different types of cells is due mainly to the length of which phase? G1 phase
What law states that the intensity of radiation at a location is inversely proportional to the square of its distance from the source of radiation? Inverse square law
What is the thickness of a material? viscosity
What model applies to biologic targets, such as enzymes, viruses, and simple cells such as bacteria? Single Target, Single Hit
What model applies to more complicated biologic systems such as human cells? Multitarget, Single hit
What is the dose that results in 37% cell survival? D37
LET stands for? Linear energy transfer
RBE stands for? Relative biologic effect
OER stands for? Oxygen enhancement ratio
What is radiation induced structural change in chromosomes? Cytogenetic damage
What is the breakup of large molecules into smaller molecules? Catabolism
What is the construction of large molecules from smaller molecules? Anabolism
A cell's DNA has been irradiated. What are you most concerned about? genetic damage or mutation
What phase of DNA synthesis is said to resemble a zipper opening? S phase
What is a liquid that contains dissolved substances? solution
What are the 3 types of radiation-damage to human chromosomes? Terminal deletion, dicentric formation, and ring formation
What 4 types of damage that occurs to DNA is reversible? one side rail severed, both side rails severed, cross-linking, and rung breakage
Created by: Chrslarsen