What is the role of biological detergent in the process of isolation of nucleic acid?
Biological detergents like SDS (an anionic detergent) play a crucial role in nucleic acid isolation. When added to the isolation medium, SDS makes all protein molecules anionic (negatively charged). As a result, the basic proteins that are positively charged and bound to negatively charged nucleic acids become negatively charged and dissociate from the nucleic acids. This helps separate nucleic acids from their bound proteins.
Additionally, SDS provides protection to nucleic acids by preventing the activities of nucleases (deoxyribonuclease and ribonuclease) that are released during cell lysis. This ensures that the isolated nucleic acids remain intact and are not degraded during the extraction process.
Explanation
The textbook clearly explains that detergents like SDS serve two main functions: (1) they decrease the interaction between proteins and nucleic acids by making proteins anionic, causing them to dissociate from nucleic acids, and (2) they prevent nuclease activity, protecting nucleic acids from degradation. Both points are essential for a complete 2-mark answer.