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Bacteriology is the branch of microbiology dealing with the structure and properties of bacteria, particularly those properties which are important industrially or medically. Bacteria (named because they looked, to the first people to study them, like little sticks, bacteria in Greek) constitute a highly varied group of simple organisms, usually single-celled. They are difficult to classify in relation to plants or animals, but are usually considered to be more closely aligned to the plant kingdom than the animal kingdom. All bacteria are prototypes, meaning that they have a more simple cellular organization than plants and animals, which are eukaryotes. Prokaryotes have no chromosomes.
Ferdinand Cohn published the first classification of bacteria in 1872, but subsequent attempts to impose some kind of taxonomic order on the huge range of bacteria have met with great difficulty. Bacteria are classified by their shape, size and response to certain chemical stains. Robert Koch, a student of Cohn\'s, was a pioneer in the field who worked with the bacteria which cause important diseases such as anthrax and tuberculosis. Bacterial cells are much simpler in genetic and structural terms than the cells of larger organisms; they multiply extremely rapidly, by dividing every 20 minutes under suitable conditions, and they have the ability to adapt very rapidly to environmental changes. For these reasons they are extensively used in modern biochemical research. Pathogenic (disease-causing) bacteria represent the minority and induce their effects by their rate of growth and by the production of substances which are toxic to the body. RB
See also abiogenesis. |
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