CH.31 Flashcards
If a macromolecule has (a) _____, it will break down into smaller molecules.
a. main-chain scission
b. point lesion
c. cross-linking
d. point mutation
b. point lesion
___ is the most radio sensitive molecule.
DNA
Half as much DNA is present in __ and __.
G1 G2
In vitro irradiation of macromolecules causes _____ damage to macromolecules.
a. repairable
b. reversible
c. irreversible
d. both A and B
d. both A and B
At low doses, ____ are considered to be the cellular radiation damage that results in the stochastic radiation effects observed at the whole body level.
Point lesions
The most radiosensitive macromolecule is _____.
a. protein
b. DNA
c. mRNA
d. tRNA
b. DNA
Radiation induced molecular ______ increases the viscosity of a macromolecular solution.
Cross linking
DNA is contained in the _____ of the cell nucleus.
a. proteins
b. cytoplasm
c. chromosomes
d. RNA
c. chromosomes
_____ scission is reduces not only the size of the marcromolecule but also the viscosity of the solution.
Main chain
A type of DNA damage that may not be reversible is a _____.
a. cross-linking
b. base change or loss
c. rung breakage
d. severed side rail
b. base change or loss
A ___ results in the change or loss of a base, which creates an abnormal gene.
Point mutation
Radiation damage to DNA can result in _____.
a. cell death
b. malignant disease
c. genetic changes
d. any of the above
d. any of the above
The radio lysis of water results in the formation of ___and ____.
Ions and free radicals
Molecular lesions of DNA are called _____.
a. point mutations
b. broken side rails
c. cross-linking
d. rung breaks
a. point mutations
___ is an uncharged molecule that contains a single unpaired electron in the outer shell.
Free radical
The principal radiation interaction within the human body is with _____.
a. DNA
b. macromolecules
c. water
d. RNA
c. water
If the initial ionizing event occurs on the target molecule, the effects of radiation is _____.
Direct
The disassociation of water molecules following irradiation is termed _____.
a. radiolysis
b. ionization
c. cross-linking
d. point mutation
c. cross-linking
The principle effect of radiation on humans is ___.
Indirect
When an atom of water is irradiated it first dissociates into _____.
a. two water atoms
b. an ion pair
c. free radicals
d. hydrogen peroxide
b. an ion pair
What are the types of damage that can occur in DNA?
One side rail, both side rails, cross linking, rung breaking
An indirect effect from ionizing radiation occurs on a _____ molecule.
a. target
b. DNA
c. water
d. free radical
c. water
Ionizing events from irradiation are considered to be direct effects if they occur with _____ molecules.
a. water
b. DNA
c. protein
d. both A and B
b. DNA
The principal radiation interactions within the human body are assumed to be _____.
a. indirect effects
b. direct effects
c. DNA damage
d. cell destruction
a. indirect effects
Outside the body or outside the cell
in vitro
Radiation-induced structural change in chromosomes.
cytogenetic damage
c. Radiation damage that consists of a molecular lesion of the DNA and causes genetic mutation.
Point mutation
d. A short-lived, highly reactive, uncharged molecule containing a single unpaired electron in the outermost shell.
free radical
e. The radiobiologic theory that says for a cell to die, after radiation exposure, its target molecule must be inactivated.
Target theory
The viscosity of a solution determines the degree of main chain scissions
Viscosity
Some macromolecules have side structures that behave as though they have a sticky substance on their ends, and they attach to another macromolecule or to another segment of the same molecule.
Crosslinking
- Two OH* free radicals can join to form _____ molecules.
a. organic free radical
b. hydroperoxyl
c. hydrogen peroxide
d. DNA
c. hydrogen peroxide
h. Occurs when a radiation interaction occurs with the target
Radiation hit
- Free radicals can be damaging because they are _____.
a. unstable
b. highly reactive
c. radioactive
d. both A and B
d. both A and B
the process that creates energy for a cell by breaking down molecular nutrients that are brought to and diffused through the cell membrane
Catabolism
the probability or frequency of the biologic response to radiation as a function of radiation dose. Disease incidence increases proportionally with dose, and there is no dose threshold.
Stochastic effect
What is the difference b/w catabolism and anabolism?
- Catabolism is the breakup of large molecules into smaller molecules. Anabolism is the construction of large molecules from smaller molecules
Name the 3 principle observable effects of DNA irradiation.
cell death, genetic damage, and malignant disease
What is the difference b/w 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 interaction is with some other molecule, resulting in the formation of free radicals, which then transfer this excess energy to the DNA.
*In what phase of the cell cycle does the DNA ladder open up in the middle of each rung and consist of only a single chain?
- Synthesis (S) phase
