Salt plays a crucial role in the process of DNA extraction. When cells are lysed (broken open) to release DNA, various components, including proteins, lipids, and carbohydrates, are also released. The addition of salt helps to precipitate these unwanted cellular components away from the DNA.
Specifically, salt ions interact with the negatively charged backbone of the DNA, helping to stabilize the DNA molecules. This stabilization is essential because, in a solution without salt, DNA would remain dissolved and dispersed, making it difficult to isolate and purify.
Additionally, salt helps to facilitate the aggregation of DNA strands, making them clump together when alcohol is added during the extraction process. This aggregation allows the DNA to become visible as a white precipitate, which can then be collected through centrifugation or careful pipetting.
In summary, the purpose of salt in DNA extraction is to create an environment that stabilizes DNA and enables its separation from other cellular components, ultimately allowing for a successful isolation of pure DNA.