During the process of isolation of DNA, chilled ethanol is added to:

Chilled ethanol is used to precipitate DNA out of a mixture of biomolecules. Low temperature protects DNA by slowing down the activity of enzymes that could break DNA apart while ethanol, being a dehydrating agent removes water molecules bound to DNA and making it visible. Chloroform is used in the extraction process of DNA to remove proteins bound to DNA. Related Theory There are five basic steps of DNA extraction that are consistent across all the possible DNA purification chemistries: 1) disruption of the cellular structure to create a lysate. 2) separation of the soluble DNA from cell debris and other insoluble material, 3) binding the DNA of interest to a purification matrix, 4) washing proteins and other contaminants away from the matrix and 5) elution of the DNA. Caution The option Chilled isopropanol inslead of isopropanol is also correct option.