cell
(rus. клетка)
—
basic unit of a living organism, separated from the external environment by a lipid membrane, containing genetic information about itself, having its own metabolism and capable of reproduction and development.
Description
There are two types of cells: cells with no nucleus (prokaryotic cells, e.g. bacteria) and cells with a membrane-deliniated nucleus (eukaryotic cells, i.e. cells of animals and plants). Despite this and other differences all cells have similar features: they are surrounded by a cell membrane; their genetic information is stored in genes; proteins are their main structural material and biocatalyst; they are synthesised on ribosomes. As a source of energy cells use adenosine triphosphate (ATP). Viruses do not have all the attributes of cells and are not living organisms, although sometimes they are referred to as non-cellular forms of life. There are unicellular organisms consisting of a single cell (bacteria, protozoa and unicellular algae). Multicellular animals (Metazoa) and plants (Metaphyta) contain many differentiated (specialised) cells that perform different functions. All cells of a given eukaryotic organism (except for sex cells), including stem cells, have the same DNA content. Cells of various organs and tissues, for example, bone cells and nerve cells, differ due to regulation of gene expression. Stem cells can differentiate into specialised cells of tissues and organs . A new treatment approach, stem cell therapy, is being developed, which consists of transplanting living cells into humans to replace lost, inactive or damaged cells and restore the structure and functions of tissues and organs.
Authors
- Naroditsky Boris S.
- Nesterenko Lyudmila N.
- Shirinsky Vladimir P.
Sources
- Alberts B., Johnson A., Lewis J. et al. Molecular Biology of the Cell. 4th ed. — N.Y.: Garland Publishing, 2002. — 265 p.
- B. Glick, J. Pasternak. Molecular Biotechnology: Principles and Applications of Recombinant DNA. — 3rd ed. Sigma Publishing, 2003, 784 pp.
- Cell (biology) // Wikipedia, the free encyclopedia. — http://en.wikipedia.org/wiki/Cell_(biology) (reference date 12.12.2011).