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Chapter 31: Molecular Radiobiology

Terms in this set (34)

If a macromolecule has a ______, it will break down into smaller molecules.
Point lesion
In vitro irradiation of macromolecules causes _____ damage to macromolecules.
Repairable
Reversable
The most radiosensitive macromolecule is:
DNA
DNA is contained in the _______ of the cell nucleus.
Chromosomes
A type of DNA damage that may not be reversible is a:
Base change or loss
Radiation damage to DNA can result in:
Cell death
Malignant disease
Genetic changes
Molecular lesions of DNA are called:
Point mutations
The principal radiation interaction within the human body is with:
Water
The disassociation of water molecules following irradiation is termed:
Radiolysis
When an atom of water is irradiated it first dissociates into:
An ion pair
Two OH* free radicals can join to form:
Hydrogen peroxide molecules
Free radicals can be damaging because they are:
Unstable
Highly reactive
An indirect effect from ionizing radiation occurs on a:
Water molecule
Ionizing events from irradiation are considered to be direct effects if they occur with:
DNA molecules
The principal radiation interactions within the human body are assumed to be:
Indirect effects
In vitro
Irradiation outside of the cell or body
In vivo
Irradiation within the body
Solution
Liquid that contains dissolved substances
Main-Chain Scission
Breakage of the backbone of the long-chain macromolecule; results in the reduction of a long, single molecule into many smaller molecules, each of which still be macromolecules
Point Lesions
Radiation interaction with macromolecules also can result in disruption of single chemical bonds

Not detectable, but they can cause a minor modification of the molecule, which can cause it to malfunction within the cell.
At low radiation doses, point lesions are considered to be:
The cellular radiation damage that results in the stochastic radiation effects observed at the the whole-body level
Macromolecular synthesis
Molecular nutrients are brought to the cell and are diffused through the cell membrane, where they are broken down (catabolism) into smaller molecules with an accompanying release of energy.
Energy resulting from catabolism is most important for:
The construction or synthesis of macromolecules from smaller molecules (anabolism)
Synthesis of proteins and nucleic acids is critical to:
The survival and reproduction of cells
Metabolis
Catabolism+Anabolism
Catabolism
Reduction of nutrient molecules for energy
Anabolism
Production of large molecules for form and function
Proteins are ______ radiosensitive than nucleic acids.
Less
What is the most radiosensitive molecule?
DNA
What is the role of chromosomes within the DNA?
Control the growth and development of the cell; determine characteristics of individual
Observable principal effects that may result from DNA irradiation:
Cell death
Malignant disease
Genetic damage
Radiolysis of water:
When water is irradiated, it dissociates into other molecular products
If the initial ionizing event occurs on the target molecule:
The effect of radiation is direct
The principal effect of radiation on humans is:
Indirect
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