Which of the following is a common method of DNA extraction from cells?

The chosen answer accurately identifies a fundamental step in the DNA extraction process. The use of a lysis buffer is critical as it serves to break down the cell membranes, allowing for the release of DNA into the solution. Lysis buffers typically contain detergents and enzymes that disrupt the lipid bilayer of the cell membrane and the nuclear envelope, leading to the release of not only DNA but also RNA and proteins. This initial step is crucial for successfully isolating DNA from other cellular components.

In the context of DNA extraction, other methods mentioned may play supportive roles but do not primarily focus on the initial step of cell lysis. For instance, while the addition of alcohol is utilized to precipitate DNA once it is released, that step follows the lysis phase. Denaturing proteins with heat can assist in purification steps but is not a standalone method for extracting DNA. Finally, applying electrical currents is associated with separating DNA fragments during gel electrophoresis rather than the extraction process itself. Thus, the use of a lysis buffer is the essential, common method that effectively initiates the process of obtaining DNA from cells.