Biophysics notes-CELL FRACTIONATION

Cell- fractionation is the technique by which cells are cracked, releasing cell components (ER, mitochondria, plastids, lysosomes, Golgi bodies, nuclei, chromosomes, etc.) and macromolecules as pure fractions for the study of their molecular nature and functions. Essentially, it involves two processes namely homogenization and centrifugation.

Homogenization

This is the disruption of plasma membrane and cell wall and the disintegration or lysis of the cell by mechanical or chemical methods, or by insonation, (sonic oscillation). Mechanical homogenization is accomplished with the help of suitable homogenizers such as glass homogenizer, waring blender, etc. Chemical homogenization is effected by using proteolytic or lipolytic enzymes or detergent solutions. Insonation involves the application of ultra sonic waves or vibrations with the help of a sonifier. The product of homogenization is called homogenate or lysate. It is then subjected to centrifugation. Homogenization of cells is usually done in an aqueous medium. The most commonly used media are sucrose solutions of various concentrations.