2.2 Cell fractionation

Although electron microscopy has allowed the appearance of cell organelles to be studied, elucidation of their function required a method for separating the different organelles from the remaining cell components so that their biochemical properties could be studied. This vital link between cell structure and biochemistry was made possible by developments in a technique known as cell fractionation (Box 1). This procedure is carried out in two steps: disruption of the cells to release the subcellular components, followed by centrifugation (described below) to separate the components on the basis of their mass or density.