cell biology Cell biology (also cellular biology or cytology) is a branch of biology that studies the structure, function, and behavior of cells. All living organisms are made of cells. A cell is the basic unit of life that is responsible for the living an ...

, cell fractionation is the process used to separate cellular components while preserving individual functions of each component. This is a method that was originally used to demonstrate the cellular location of various

biochemical Biochemistry, or biological chemistry, is the study of chemical processes within and relating to living organisms. A sub-discipline of both chemistry and biology, biochemistry may be divided into three fields: structural biology, enzymology, ...

processes. Other uses of subcellular fractionation is to provide an enriched source of a

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...

for further purification, and facilitate the diagnosis of various disease states.

Homogenization

Tissue is typically homogenized in a

buffer solution A buffer solution is a solution where the pH does not change significantly on dilution or if an acid or base is added at constant temperature. Its pH changes very little when a small amount of strong acid or base is added to it. Buffer solution ...

that is isotonic to stop osmotic damage. Mechanisms for homogenization include grinding, mincing, chopping, pressure changes, osmotic shock, freeze-thawing, and

ultrasound Ultrasound is sound with frequency, frequencies greater than 20 Hertz, kilohertz. This frequency is the approximate upper audible hearing range, limit of human hearing in healthy young adults. The physical principles of acoustic waves apply ...

. The samples are then kept cold to prevent enzymatic damage. It is the formation of homogenous mass of cells (cell homogenate or cell suspension). It involves grinding of cells in a suitable medium in the presence of certain enzymes with correct pH, ionic composition, and temperature. For example,

pectinase Pectinases are a group of enzymes that breaks down pectin, a polysaccharide found in plant cell walls, through hydrolysis, transelimination and deesterification reactions. Commonly referred to as pectic enzymes, they include pectolyase, pectozym ...

which digests middle lamella among plant cells.

Filtration

This step may not be necessary depending on the source of the cells. Animal tissue however is likely to yield connective tissue which must be removed. Commonly, filtration is achieved either by pouring through

gauze Gauze is a thin, translucent Textile, fabric with a wikt:loose, loose open Weaving, weave. In technical terms, "gauze" is a weave structure in which the weft yarns are arranged in pairs and are crossed before and after each Warp (weaving), w ...

or with a suction filter and the relevant grade ceramic filter.

Purification

Purification is achieved by differential centrifugation – the sequential increase in gravitational force results in the sequential separation of organelles according to their

density Density (volumetric mass density or specific mass) is the ratio of a substance's mass to its volume. The symbol most often used for density is ''ρ'' (the lower case Greek letter rho), although the Latin letter ''D'' (or ''d'') can also be u ...

References

{{Reflist Biochemical separation processes Fractionation Laboratory techniques

Homogenization

Filtration

Purification

See also

References