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Radioactivity can cause Damage to Living Cells.

Ionising radiation can cause damage to the DNA in cells.
Ultraviolet waves and x-rays also cause the same kind of damage.
DNA is the name given to the long molecules in the nucleus.
DNA is a double helix and contains the genes and chromosomes.

The word nucleus is used in biology, chemistry and physics.
In biology the nucleus is the middle part of cells containing DNA.
In chemistry and physics the nucleus is the centre of an atom.

How does
Radioactivity Damage Living Cells?

Radiation of a high intensity and long exposure will cause so much
damage to a living cell that it will die. This is used for the technique
of sterilisation. Intensity means the amount of radiation in an area.
means the length of time that the radiation that is present.

Low intensity radiation can cause small changes to the DNA
which may alter the cell without killing it. A change in
the DNA of a cell is called a mutation.  Some mutations
are harmless and make no difference to the organism,
some may be beneficial (good), and some may be harmful.

How does Radioactivity cause Cancer?

A harmful mutation will increase in number when the cell copies
by mitosis. The cells with the harmful mutation will continue
to grow in an uncontrolled way and may then spread to other
parts of the body. This is what is called cancer. The chance of
radiation causing cancer increases as the exposure and
intensity increases. Cancer can be treated using radiotherapy.

Which Type of Radioactivity is the Most Harmful?

The three types of radioactivity cause different amounts of damage
depending on whether they are inside or outside of the body.

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