What is a bacterium?
The microscopic world is rich in various types of organisms, among which bacteria also take their place. So what is a bacterium? It is a single-celled (sometimes 2-, 3-cell, like gonococcus) organism, the size of which is very small - ranging from 0.5 to 500 micrometers.Bacteria are prokaryotes (lower organisms), in which, unlike eukaryotes, genetic material is not formed into the nucleus, but freely floats in the cytoplasm in the form of circular DNA.
What are the bacteria
Science knows about a thousand species of bacteria, whereas, presumably, they are much more - about a million species. Bacteria are distinguished according to the shape of cells - bacilli (cells are elongated in rod-shaped form), cocci (spherical cells), vibrios (comma-shaped cells), spirochetes (spiral-shaped cells).
Bacteria also differ depending on the ability to live and multiply in the presence or in the absence of oxygen (respectively, aerobes and anaerobes).
Bacteria can be the cause of many diseases. For the prevention of some of them, vaccination is recommended.You can learn more about this prevention in our article What is a vaccine.
The word "bacterium" is used, for example, in the sentences: "E. coli is a bacterium that lives in the human intestine", "Bacteria that are present in yogurt are extremely useful for the work of the human intestine." By the way, those who for some reason (treatment with antibiotics, stress) die lactic acid bacteria that live in the intestines, can become ill with dysbacteriosis.