Cellefraksjoner

Cellefraksjoner, a term originating from the Swedish word for "cell fractions," refers to the isolation and study of specific components or organelles within a cell. This process is crucial in biochemistry and molecular biology for understanding the function of individual parts of the cell without the complexity of the entire living system.

The primary goal of cell fractionation is to separate cellular components based on their physical properties, such as size, density, or solubility. A common technique used is differential centrifugation. In this method, cells are first lysed, or broken open, to release their internal contents. The resulting homogenate is then subjected to a series of centrifugation steps at increasing speeds. Heavier and larger organelles, like nuclei and cell walls, will pellet at lower speeds. As the speed increases, progressively smaller and less dense components, such as mitochondria, lysosomes, and eventually ribosomes and soluble proteins, can be separated.

Another technique is density gradient centrifugation, where the homogenate is layered onto a gradient of a dense substance, such as sucrose. During centrifugation, particles move through the gradient until they reach a level where their density matches that of the surrounding medium, allowing for finer separation of organelles with similar sizes but different densities.

The isolated cell fractions are then analyzed using various biochemical and molecular techniques. This can include enzyme assays to identify the specific metabolic activities of each fraction, protein analysis using electrophoresis, or nucleic acid studies. By studying these isolated fractions, researchers can determine the location of specific enzymes, map metabolic pathways, and understand the roles of different organelles in cellular processes like energy production, protein synthesis, and waste removal. Cell fractionation remains a fundamental tool in biological research.