How It Works: Why Radiation Is Biologically Harmful

⚙️ How It Works: Why Radiation Is Biologically Harmful

Radiation causes harm by ionisation — stripping electrons from atoms in biological molecules. When DNA in a cell nucleus is ionised, the resulting chemical changes can break DNA strands or alter the base sequences.

If DNA damage occurs in a normal body cell: the cell may die (radiation sickness at high doses) or the DNA repair mechanisms may incorrectly repair the break, creating a mutation. If the mutation affects genes that control cell division, the result can be uncontrolled division — cancer.

If DNA damage occurs in a reproductive cell (sperm or egg), the mutation can be passed to offspring — causing heritable genetic mutations in the next generation.

Why alpha is most dangerous inside the body: Although alpha cannot penetrate skin from outside, if an alpha-emitting material is inhaled or swallowed, it deposits all its energy in a tiny volume of tissue nearby. This concentrated ionisation causes severe, localised DNA damage.