"Historically the International Union of Pure and Applied Chemistry (IUPAC) also used the term radical for any joined up group of atoms forming a side-group of a larger molecular entity, e.g. carboxyl radical. By contrast, unpaired electron species were called free radicals. However the first use of radical has been abandoned such that IUPAC uses the term group instead, therefore carboxyl group not radical. So it has been decided that the descriptor 'free' is now superfluous as in general radicals are free 1."
"In cells, water is the most abundant source of radiation-produced radicals, and excitation and ionisation results in formation of hydrogen (∙H) and hydroxyl (∙OH) radicals"
"H2O -> ∙H + ∙OH"
"oxygen combines with the hydrogen radical to form the highly reactive hydroperoxyl radical (∙HO2)"
"by damage to genetic material (DNA/RNA)"
Expected headings
"Radical formation"