AP BIOLOGY

Detailed explanation-1: -Ethidium Bromide (EtBr) is sometimes added to running buffer during the separation of DNA fragments by agarose gel electrophoresis. It is used because upon binding of the molecule to the DNA and illumination with a UV light source, the DNA banding pattern can be visualized.

Detailed explanation-2: -The most commonly used fluorescent DNA stain is Ethidium Bromide (EtBr). Individual EtBr molecules can squeeze between neighboring base pairs in a DNA double helix in a process known as “intercalation”. When excited with UV light, any EtBr intercalated into the DNA fluoresces and produces a bright orange light.

Detailed explanation-3: -Ethidium bromide (EtBr) or 3, 8-Diamino-5-ethyl-6-phenylphenanthridinium is commonly used as a non-radioactive marker to stain DNA in order to identify and visualize nucleic acid bands in electrophoresis and other gel-based methods of nucleic acid separation.

Detailed explanation-4: -Nucleotide visualization. Ethidium bromide binds DNA by intercalating between base pairs, which causes the DNA helix to partially unwind. Deoxyribonucleic acid bands in gels stained with ethidium are fluorescent on exposure to ultraviolet light.

Detailed explanation-5: -Ethidium bromide is a useful and practical stain for the fluorescence microscopy of tissue sections and, in combination with enzymatic digestion of RNA, provides a simple way to differentially localize DNA and RNA.