Plasmid DNA Extraction Quiz

Alkaline Lysis Method: Solution I

• Glucose is added to Solution I to provide a stabilizing effect on the cell membranes, preventing cell lysis during the initial stages of the process.
• EDTA (Ethylenediaminetetraacetic acid) is a chelating agent that binds to magnesium and other divalent cations, disrupting the activity of DNases and preventing DNA degradation.
• Tris.Cl (Tris-HCl) is a buffer that helps maintain the pH of the solution, ensuring optimal conditions for the subsequent steps in the process.

Alkaline Lysis Method: Solution II

• Solution II contains 0.2N NaOH and 1% SDS, which work together to lyse the cells and release the DNA.
• The 0.2N NaOH denatures the cell membranes, allowing the SDS to solubilize the lipids and release the DNA.
• SDS (Sodium dodecyl sulfate) is a detergent that disrupts the cell membrane, solubilizing the lipids and releasing the DNA.

Alkaline Lysis Method: Solution III

• Solution III contains a high concentration of potassium acetate, which helps to precipitate the SDS, proteins, and other impurities, allowing the DNA to be recovered.