Cetyltrimethylammonium bromide is

The correct answer is cationic detergent.

Key Points

• Cetyltrimethylammonium bromide (CTAB) is a cationic detergent used in various applications, including biochemistry and molecular biology.
• Cationic detergents are positively charged surfactants that are effective in disrupting lipid bilayers and proteins.
• CTAB is commonly used for lysing cells and solubilizing membrane proteins in DNA and RNA extraction protocols.
• Unlike anionic detergents (negatively charged), cationic detergents like CTAB can bind to negatively charged molecules, such as nucleic acids and proteins.
• CTAB is widely used in research for its ability to precipitate nucleic acids selectively, especially in plant DNA extraction methods.

Additional Information

• Cationic Detergents:
  • These are surfactants with a positive charge on their hydrophilic end, making them effective in disrupting negatively charged cell membranes.
  • They are commonly used in disinfectants, fabric softeners, and hair conditioners due to their antimicrobial properties.
  • Cetyltrimethylammonium bromide is an example of a quaternary ammonium cationic detergent.
• Detergent Classifications:
  • Detergents are classified into three types: anionic, cationic, and nonionic, based on the charge of their hydrophilic head group.
  • Anionic detergents (e.g., sodium lauryl sulfate) carry a negative charge, while nonionic detergents (e.g., Triton X-100) have no charge.
  • Cationic detergents are less commonly used in household cleaning but are effective in specialized applications like antimicrobial treatments.
• Structure of CTAB:
  • CTAB consists of a hydrophobic tail (cetyl group) and a hydrophilic, positively charged head (quaternary ammonium group).
  • This amphiphilic structure makes CTAB an effective surfactant for breaking down cell membranes and solubilizing hydrophobic substances.
• Applications of CTAB:
  • In molecular biology, it is used in DNA extraction protocols, especially for plants, due to its ability to remove polysaccharides and other contaminants.
  • It is also used in the synthesis of nanoparticles and as a stabilizing agent in nanotechnology.
  • CTAB is an effective antimicrobial agent, often incorporated into disinfectants and antiseptics.