The use of a blender in the process of DNA extraction is to aid in the breakdown of cell walls and cell membranes, chopping them up to get access to the contents inside.
Need for Cellular Disruption
DNA extraction from a cell requires that the DNA be separated from the rest of the cellular contents. DNA normally exists inside the nuclear membrane and is associated with a variety of proteins and cellular structures. In animal cells, the DNA is not only encased inside a cell membrane, but it is further encased inside a nuclear membrane. In plant cells, there is the additional barrier of the cell wall. Cell walls, cellular and nuclear membranes are highly ordered structures that are designed to hold onto their contents.
Use of a Blender
To extract the DNA, these structures must be broken down. Scientists use variety of techniques to achieve this. Often, they add a detergent such as SDS (sodium dodecyl sulfate) to a solution of cells to poke holes in the membranes. Often, however, that is not enough. This is where a blender can help.
Analogy
If you were trying to get the seeds out of a tomato, you could squeeze or poke holes in its skin, but a blender will really chop up the tomato and release the seeds. Similarly, in DNA extraction, the blender chops up the cells and releases the contents inside.
Blenders in the lab
The ordinary household Waring blender was used in an experiment that showed DNA was the inheritable genetic material of a cell. The experiment is known as the classic Hershey-Chase experiment, named for Alfred Hershey and Martha Chase, the two investigators.
Hershey-Chase Experiments
The Hershey-Chase experiment showed that it was the viral DNA, not the viral proteins, that contained genetic material. When a bacterial virus particle known as phage T4 attached to a bacterium, the virus injected its DNA into the bacterial cells, while leaving the viral protein coat on the outside. Hershey and Chase showed that the viral infection was unaffected by the agitation in the Waring blender, which removed the empty viral protein coats from the bacterial surface.
Blenders, therefore, are not just used in DNA extraction but are also useful to perform the mechanical chopping necessary for other laboratory tasks.
Tags: contents inside, encased inside, genetic material, Hershey-Chase experiment, inside nuclear, inside nuclear membrane