(i) In prokaryotes, the bacterial cells are treated with certain lysozymes to break the cell wall.
(ii)
In eukaryotes plant cell wall can be removed by treatment with
cellulase; in case of fungi, it can be removed by treatment with
chitinase.
Common steps of prokaryotes and eukaryotes:
After the
boundary is broken, the nucleic acid (along with other compounds) is
released from the cell. The DNA exists with certain proteins and RNA; so
they have to be removed. Proteins are removed by treatment with
proteases and RNA by treatment with ribonuclease. Other molecules are
removed by appropriated treatment. Then DNA is precipitated out after
the addition of chilled ethanol.