Practice question

Densitometry involves scanning electrophoretic gels after staining with dyes like ethidium bromide or Coomassie blue. A densitometer measures absorbance or fluorescence intensity of each band. The peak area and height are directly proportional to concentration of macromolecule present. By comparing with known standards, absolute amount of DNA, RNA or protein can be estimated. It provides quantitative analysis beyond qualitative visualization, unlike simple band counting or purity assessment by spectrophotometry ratio. Thus quantification is its primary application in molecular biology laboratories.