Question

How does ethidium bromide work? The molecule inserts itself between _________________ in DNA, hence "tagging it". When exposed to UV light, it fluoresces enabling us to see where the DNA has migrated.

Answer 1

Ethidium bromide works by intercalating itself between the stacked nitrogenous bases of the DNA double helix, 'tagging' the DNA. When exposed to UV light, it fluoresces, enabling us to see where the DNA has migrated on the gel.

Step-by-step explanation:

Ethidium bromide (EtBr) is a fluorescent molecule that is commonly used to visualize nucleic acids on an agarose gel. It works by intercalating itself between the stacked nitrogenous bases of the DNA double helix, which effectively 'tags' the DNA. When exposed to UV light, EtBr fluoresces, allowing us to see where the DNA has migrated on the gel.