NOCTI Biotechnology Practice Test

Purifying DNA from a sample using both physical disruption and chemical agents is called DNA isolation (often referred to as DNA extraction). The goal is to break open cells to release the DNA, then separate it from proteins, lipids, and other cellular debris, and finally recover clean DNA for further use. Physical steps like grinding, homogenization, or centrifugation help separate cellular components by size and density. Chemical steps use detergents to lyse membranes, salts and enzymes to remove proteins and other contaminants, and often organic solvents or alcohol to precipitate and collect the DNA. The result is purified DNA that can be used in downstream analyses. The other options describe equipment or tools (a device for transferring small volumes, a safety cabinet, or a measuring container), not the purification process itself.