Practice question

Fluorescent quantification of DNA employs DNA-binding fluorochromes for sensitivity beyond UV absorbance. SYBR Green I is a cyanine dye that exhibits extremely low fluorescence when free but over 1000-fold enhancement upon intercalation into minor groove of double-stranded DNA. This allows specific quantitation of dsDNA even with contaminants present. Coomassie Blue stains proteins, DAPI binds AT-rich dsDNA but is used mainly for microscopy, and TRIS is a buffer. SYBR Green is standard for real-time PCR quantification and fluorometric assays with high specificity and linearity.