Practice question

Ethidium bromide is cationic phenanthridine dye with flat polycyclic ring system ideally dimensioned to intercalate between nitrogenous bases, binding with high affinity and enhancing fluorescence twentyfold enabling visualization of DNA under UV. Intercalation lengthens and rigidifies duplex, inhibits topoisomerases, and promotes polymerase slippage leading principally to frameshift events rather than point substitutions. Due to potent mutagenic and potential carcinogenic activity, laboratory handling requires protective measures and decontamination with activated charcoal or hypophosphorous acid before disposal. This principle illustrates essential molecular mechanisms governing replication fidelity and mutation fixation relevant for exam interpretation.