Radiation Effects on Cells
Slide 5 of 16
Ionizing radiation can have two effects on living organisms, direct and indirect. Direct effects are observed through ruptured plasma membranes, disruption of mitochondria processes, release of digestive enzymes from the lysosome, etc. The cells ultimate fatality is due to a combination of all misfunctions. Generally this kind of damage results at particularly high doses ranging from 500 to 5,000 rads.
Interuption of cell reproduction occurs when the nucleus has been directly impacted. The production of DNA can be delayed for a short period of time to indefinately in which case the cell dies. The range of doses at which this phenomenon occurs is highly variable. A more likely effect is chromosomal aberration. An aberration is a change in the normal shape of the chromosome. These changes are measureable after an exposure of 35 rem. Keep in mind other chemicals cause aberrations as well but radiation seems to cause particular types, deletion, ring and dicentric.*
* Source: Basic Radiation Protection Technology, 1994.