Cell biology (formerly cytology, from the Greek kytos, “contain”) is a scientific discipline that studies cells – their physiological properties, their structure, the organelles they contain, interactions with their environment, their life cycle, division and death. This is done both on a microscopic and molecular level. Cell biology research encompasses both the great diversity of single-celled organisms like bacteria and protozoa, as well as the many specialized cells in multicellularorganisms such as humans, plants, and sponges.
Knowing the components of cells and how cells work is fundamental to all biological sciences. Appreciating the similarities and differences between cell types is particularly important to the fields of cell and molecular biology as well as to biomedical fields such as cancer research and developmental biology. These fundamental similarities and differences provide a unifying theme, sometimes allowing the principles learned from studying one cell type to be extrapolated and generalized to other cell types. Therefore, research in cell biology is closely related to genetics, biochemistry, molecular biology, immunology, and developmental biology.
Techniques used in Cell biology
Cells may be observed under the microscope. This includes the Optical Microscope, Transmission Electron Microscope, Scanning Electron Microscope, Fluorescence Microscope, and by Confocal Microscopy.
Several different techniques exist to study cells are
- Cell culture is the basic technique of growing cells in a laboratory independent of an organism.
- Immunostaining, also known as immunohistochemistry, is a specialized histological method used to localize proteins in cells or tissue slices. Unlike regular histology, which uses stains to identify cells, cellular components or protein classes, immunostaining requires the reaction of an antibody directed against the protein of interest within the tissue or cell. Through the use of proper controls and published protocols , specificity of the antibody-antigen reaction can be achieved. Once this complex is formed, it is identified via either a “tag” attached directly to the antibody, or added in an additional technical step. Commonly used “tags” include fluorophores or enzymes. In the case of the former, detection of the location of the “immuno-stained” protein occurs via fluorescence microscopy. With an enzymatic tag, such as horse radish peroxidase, a chemical reaction is carried out that results in a dark color in the location of the protein of interest. This darkened pattern is then detected using light microscopy.
- Computational genomics is used to find patterns in genomic information 
- DNA microarrays identify changes in transcript levels between different experimental conditions.
- Gene knockdown mutates a selected gene.
- In situ hybridization shows which cells are expressing a particular RNA transcript.
- PCR can be used to determine how many copies of a gene are present in a cell.
- Transfection introduces a new gene into a cell, usually an expression construct
Purification of cells and their parts Purification may be performed using the following methods:
- Cell fractionation
- Release of cellular organelles by disruption of cells.
- Separation of different organelles by centrifugation.
- Flow cytometry
- Proteins extracted from cell membranes by detergents and salts or other kinds of chemicals.