DNA is obtained by treating the bacterial cells/plant or animal tissue with enzymes such as lysozyme (bacterial), cellulase (plant cells), chitinase (fungus). As we know that genes are present on long molecules of DNA intertwined with proteins like histones, the RNA can be removed by treating with ribonuclease while proteins can be removed by treating with protease. The purified DNA finally precipitates out after the addition of chilled ethanol. This is seen as a collection of fine threads in suspension.