Most bacteria can easily be lysed by heating to a hightemperature, thus eliminating the need for a separate DNAextraction step prior to DNA amplification by PCR. Probioticbacteria are notoriously difficult to lyse, requiring enzymatic orphysical disruption methods. Explain why (think about gram identityand the environmental conditions for probiotic bacteria).
Eukaryotic cells also require DNA extraction steps, unlike mostbacteria. Explain why (think about the differences in cellstructure).
Many DNA extraction protocols include a step where DNA isprecipitated from solution, thus enabling the isolation of pureDNA. This step involves the addition of salt and alcohol. Explainwhy the addition of salt and ethanol causes DNA to precipitate froman aqueous solution. (Think about the structure of DNA and itsinteraction with an aqueous solvent).
