Chapter 32 - Cellular Radiobiology Flashcards
The response of the cell is either
cellular transformation or cell death
can result in a late stochastic effect at the human level
Cellular transformation
can result in an early deterministic effect at the human level
Cell death
Most effects on cells results in _______ because of recovery and repair metabolic processes
no response
According to the __________, for a cell to die after radiation exposure, its target molecule must be inactivated
Target theory
______, the target molecule is located within the cell nucleus
DNA
Originally, it was used to represent cell lethality. It can be used equally well, however, to describe non-lethal radiation-induced cell abnormalities.
target theory
occur through both direct and indirect effects
hits
When a hit occurs through indirect effect, the size of the target appears _________ because of the mobility of the free radicals.
considerably larger
with low LET radiation, in the absence of oxygen, the probability of a hit on the target molecule is ____ because of the relatively large distances between ionizing events
low
If oxygen is present, free radicals are formed and the volume of effectiveness surrounding each ionization is ____
enlarged
early radiation experiments at the cell level were conducted with simple cells, such as ____
bacteria
Normal cells are planted individually and are incubated for 10 to 14 days, they divide many times and produce a visible colony that consists of many cells.
Cell cloning
A higher radiation dose leads to the formation of _____
fewer colonies
The lethal effects of radiation are determined by observing ______, not cell death
cell survival
This model applies to biologic targets, such as enzymes, viruses, and simple cells such as bacteria
Single-target, single-hit
This model applies to more complicated biologic systems such as human cells
multi-target, single-hit
it interacts randomly with matter
radiation
complex biologic specimens such as human cells are thought to have
more than a single critical target
the multi-target, single-hit model of cell survival is characteristic of human cells that contain
two targets
When human cells replicate by mitosis, this average time from one mitosis to another is called
cell-cycle time
