Bacteria are a diverse group of ubiquitous micro organisms all of which consist of only a single cell that lacks a distinct nuclear membrane and has a cell wall of a unique composition.
Bacteria are usually classified by means of Gram's stain, whether or not they require oxygen, and on the basis of shape. A bacterial cell may be spherical, rod-like, spiral, comma-shaped, corkscrew-shaped, or filamentous, resembling a fungal cell. The majority of bacteria range in size from 0.5 to 5 mm. Many are motile, bearing flagella, possess an outer slimy capsule, and produce resistant spores. In general bacteria reproduce only asexually, by simple division of cells, but a few groups undergo a form of sexual reproduction. Bacteria are largely responsible for decay and decomposition of organic matter, producing a cycling of such chemicals as carbon, oxygen, nitrogen, and sulphur. A few bacteria obtain their food by means of photosynthesis, some are saprophytes, and others are parasites, causing disease. The symptoms of bacterial infections are produced by toxins. Research Bacteria
Abbreviations
Nature
Research Bacteria