Video Transcript
Which of the following statements
correctly describes the risk of death due to receiving small doses of nuclear
radiation repeatedly at many different times that are each separated by several
days? (A) The more doses that are
received, the greater the risk of death occurring. (B) The risk of death is the same
however many doses are received.
This question asks us to consider
the risks of receiving small doses of nuclear radiation repeatedly every few
days. To answer this question, we must
consider what happens when nuclear radiation is absorbed by our cells. Nuclear radiation can transfer
energy to the cells of a person. This can result in damage to the
DNA of the cell. It can also result in the cell
dying. Damage to the DNA of a cell may
cause the cell to become cancerous. A normal cell will make copies of
itself, or replicate itself, as an organism needs new cells over time. A cancerous cell will replicate at
a faster rate than normal cells do, creating even more cancerous cells, which can
lead to death.
Cells that are killed by radiation
will be replaced by new healthy cells. But cells that become cancerous may
continue to have long-term effects on the body. Repeated small doses will have what
is called a cumulative effect. This means that even if the doses
are several days apart, the second dose adds to the damage done by the first
dose. Replacing cells killed by radiation
with healthy cells takes time. An example of this type of damage
is sunburn. Sunburn does not heal overnight,
and the skin can take several days to return to normal. Since the damage done in a day does
not heal overnight, the effect of repeated small doses close together can lead to
cumulative damage.
Additionally, one small dose of
nuclear radiation can damage cell DNA and lead to many cancerous cells, which do not
die and remain in the body over time. This increases the risk of
death. More doses received over several
days means more cells have damaged DNA and are at risk of becoming cancerous. The correct answer is therefore
option (A). The more doses that are received,
the greater the risk of death occurring.
