In a standard DNA extraction protocol, what is the primary purpose of adding detergent?

• A. To dissolve lipid bilayers and disrupt cell and nuclear membranes, releasing DNA into solution
• B. To amplify DNA by catalyzing repeated cycles of DNA replication in vitro
• C. To precipitate DNA out of solution by reducing its solubility in water
• D. To cut DNA into smaller fragments at specific recognition sequences

Answer: (A)

Verified step by step guidance

1. Understand the structure of a cell, focusing on the cell membrane and nuclear membrane, which are primarily composed of lipid bilayers.
2. Recognize that the goal of DNA extraction is to release DNA from inside the cell and nucleus into the solution for further analysis.
3. Identify that detergents are molecules that can interact with and dissolve lipid bilayers, effectively breaking down the membranes.
4. Connect that by adding detergent in the DNA extraction protocol, the lipid bilayers of the cell and nuclear membranes are disrupted, allowing the DNA to be released.
5. Differentiate this role of detergent from other steps in DNA processing, such as amplification (PCR), precipitation, or enzymatic cutting, which serve different purposes.