Question

In what two ways does radon destroy genetic information in lung tissue cells?

Answer 1

Directly or through reactive intermediates.

Explanation:

Radon is a gas that is all around us, it comes from the soil and building materials. It is radioactive and decays by emitting alpha particles. The main radiation dose does not come from radon gas itself because most will be exhaled. However, radon decays to other, short lived radionuclides that emit alpha particles.

These alpha particles cause the damage to genetic material in the lung cells. Alpha particles lose their energy over a very short distance which causes a lot of DNA damage in a few cells.

Direct DNA damage
Alpha particles can cause ionizations that lead to breaks in the DNA strands. A cell is usually able to repair DNA damage. However, alpha particles cause so much damage on a short distance that it is harder to repair and the chance on mistakes/ mutations is higher. These mutations might eventually lead to cancer.

Indirect DNA damage
It is also possible that the ionization energy of alpha particles can also create reactive intermediates or reactive oxygen species (ROS). Examples are:

• superoxide: `O_2^-` with an unpaired electron
• hydrogen peroxide `H_2O_2`

These ROS are highly reactive and can also cause damage to DNA. ROS are longer lived and can also lead to DNA damage in neighboring cells.