Biology - bacteria: types, names, harmful and useful for human life, number, form

The word "bacteria", like "viruses" and "microbes", for us from childhood, is fraught with a certain negative shade, and is associated with diseases. But is it?

Can bacteria be friends, and not enemies, protect, and not threaten? And in general, what are they like, these bacteria? About all this and much more - read below.

Who are bacteria in biology: definition

• Bacteria Living microorganisms are called that do not have a nucleus. They belong to the domain of prokaryotes, being one of the oldest life forms on the planet. These are also one of the most universal "inhabitants" of the Earth, capable of living in the depths of the soil and reservoirs, in an acidic and radioactive environment. Despite all the efforts of scientists, humanity still cannot grow them all laboratory (This is possible only relative to some species).
• The length of bacteria It makes up a few micrometers, and their shape can be very diverse. Science that studies bacteria is called bacteriology. They are a component of human microflora, bringing both benefits and causing various diseases. They are used in various areas of human activity: industry, livestock, biotechnological processes, etc.
• The word comes from the Latin language, in which, in turn, the derivative of the Greek was formed, and means the concept of “wand” - it was such bacteria, first designated by scientists.

What are bacteria, are they organisms?

• Really, bacteria are organisms, and they belong to the most ancient group of all that exist today. Their structure is quite primitive, many of the bacteria still retain the signs inherent in their ancestors, in particular, those species that are in special conditions. This is a hot sulfur or vicious environment.

Thus, today the bacterium is a primitive unicellular organism, isolated into the kingdom with the same name. At the same time, the variety of bacteria is quite large, they are different in their shape, the way of movement, the environment

Who discovered bacteria?

• The discoverer bacteria The Dutch scientist can be considered Anthony van Levngukwho was the first to detect them under a microscope and describe them. This happened in the second half of the 17th century.
• Half a century later a German scientist Christians Ehrenberg gave the name to these creatures that we use to this day - bacteria. It replaced the first name introduced by the Leveguk - animalculi.
• In the mid-19th century, French microbiologist Louis Pasteur Not only found the individual properties inherent in bacteria, but also began to study their physiology and metabolism of bacteria.
• His successor in this case was a German colleague Robert Kochwhose works on the study of tuberculosis pathogens were crowned with Nobel laureate.

What bacteria, types of bacteria exist, and their names

Bacteria is customary to classify in form. Depending on this, scientists divided them into three groups:

1. To spherical (cocci) Related to grape clusters staphylococcuswhose action provokes food poisoning, as well as purulent inflammation. But streptococcus, forming a chain of cells as a result of division, it is common to provoke inflammatory diseases.
2. Like bacteria, similar to a conventional wand, is called palchikovy. There are bacteria that form peculiar layers of protection that counteract from outside - this bacilli.
3. BacteriaHaving a convincing shape, they belong to spirals, and they are predominantly harmless. These include spirituals, spiroches.

Many bacteria got their name not only in their structure, but also depending on the effect on a particular human organ, or by the name of the disease they caused. As an example, you can cite meningococcus, which affects the brain membrane and causing meningitis, or pneumococcus, which provokes pneumonia in the lungs, and rhinitis (runny nose) is caused by rhinoviruses.

• In addition, there are names related to a particular feature. The well -known vibrion is characterized by rapid fluctuations, and proteus, named by the name of the Greek God, capable of acquiring one or another appearance, is characterized by the fact that in various organisms it acts differently.
• In addition, often bacteria are called the names of scientists who opened them: ricketsia, Shigella, brucella or, say, lamblia with salmonella.

What are harmful, pathogenic bacteria, and their names?

Among the most dangerous bacteria for humans can be distinguished:

1. The causative agent botulism, paralyzing the nervous system - botulin Clostria.
2. Salmonella Typhus abdominal, which is manifested by high temperature and severe abdominal pain. The bacterium may also not appear in symptoms, but a person remains a carrier of the disease.
3. Tetanus wand Active development in a deep wound, capable of causing tetanus. This disease, with strong convulsions, has very high mortality.
4. Everyone heard about koch stickleading to tuberculosis, which is one of the most common causes of human death. It is transmitted using airborne routes, found during a fluorographic examination.
5. E. coli is simply microflora of the intestines, but several of it serotypov lead to intestinal infections.
6. Cholera vibrio Most often found in dirty water. In the absence of treatment, cholera is quite capable of fatal.
7. Streptococci - are very dangerous because they provoke meningitis, pneumonia, etc. Streptococcal toxic shock is accompanied by heat, margins of limbs and necrosis.
8. Aspergill Smoking is mold fungusDangerous for people with weakened immunity, which affects the first place of the respiratory system.
9. Pale treponema provokes the development of syphilis. Today it is a disease completely cured in the first stages, but in a tertiary one - fraught with irreversible changes in the body and death.
10. Staphylococcus gold We have long been associated with pneumonia and meningitis, sepsis. Its danger in high resistance to antibiotics.

Useful bacteria, and their names

Bacteria that have a beneficial effect on the human body have the name of the microbiota. There are many of them in a person - millions:

1. In the intestine, first of all, the beneficial effect has lacto and bifidobacteria. These include acidophilic stick, anaerobic milk-acid bacteria. It is important to maintain their required amount by consuming fermented milk products.
2. In the skin and respiratory tract, microorganisms related to staphyl-, strept- and micrococcus. They help in their habitat, but if they get into the wound or, for example, when an overabundance leads to diseases.

The number of bacteria on planet Earth

• It is calculated that on earth from above 1.4 million bacteria. During the calculation of this figure, scientists had to resort to the construction of phylogenetic trees, using mathematics and analyzing certain varieties of RNA. This made it possible to track the change in species and the evolution of bacteria.
• It turned out that some bacteria disappear in the process of evolution, their total number is constantly increasing, and today, if we take the general biomass on Earth as a reference point, bacteria are inferior only to plants.

Forms of bacteria, appearance: examples

• As already mentioned, bacteria can be spherical. They are represented by cocci. Micro - these are cells that are located separately; diplomatic - in pairs, staphylo - clusters, strepto - chain; as well as Sarcin (packages from 8 cells). Their size is up to 1 μm.
• Palochkovite bacteria is characterized by a direct shape, they have up to 8 microns in length and up to 2 microns - in thickness. The form can be wrong, up to a branching, which they have, for example, actinomycet. If the stick is slightly curved in shape - it is called vibricon.

• You can also be called rickest, chlamydiawhich is outside the cells of the cell, mycoplasmas, which do not have a cell wall, etc.
• The bacteria of convincing forms resemble a spiral, such as Spiril, similar to a corkscrew. But helicobacter Similar to its bends to the wings of the seagulls in flight. It is also close to this type of spirochet bacteria, which has a spiral shape and has mobility. Leptospir the same - with frequent curls that resemble a twisted rope.

What are bacteria made of?

• Cell wall bacteria Contains polysaccharides, proteins, lipids. Basically, the wall consists of multilayer peptidoglycan. The wall also contains an outer membrane, which with its three -layer structure is similar to a cytoplasmic (internal) membrane. Both membranes consist mainly of lipids.
• External membrane From the inside it consists of phospholipids, the outer layer is lipopolysaccharides. The space between the membranes is filled with enzymes. The inner membrane has three layers, its structure is phospholipids in two layers and integral proteins.

• The cytoplasm is proteins, ribonucleic acids, ribosomes. There are also spare nutrients: glycogen, Volutin, polysaccharides.
• An analogue of the nucleus can be called nucleoid, located in the center and representing a looped dual -stranded DNA. Nucleoid does not have a nuclear shell and a nuclear. Fonnees are not represented.
• In bacteria, you can also observe the mucous structure with clear boundaries, which is called the capsule. It contains polysaccharides, polypeptides.
• Flagellum - This is a thin thread, longer than the cell itself (up to 15 microns), starting with the inner membrane. Lurges reaches only 20 Nm thick and have discs with which they are attached to the wall.
• And, finally, adverse conditions for bacteria can provoke the formation of a dispute in a bacterial cell, which can not only persist for a long time, but also germinate.

In what conditions can bacteria exist?

• As practice shows - in almost any, from bubbling geysers, inside of which the temperature conditions are the same as in a boiling kettle - before 100 C °. Oil, acid - this environment also does not scare bacteria, and they can exist in those conditions where a more perfect organism will not survive.
• There is an assumption that space is also populated by some types of bacteria, and this hypothesis has become the basis for one of the versions explaining the origin of life on Earth.

How bacteria propagate, propagate: scheme

• The method of propagation of bacteria inherent in all unicellular organisms - this division. It gives the existence of two subsidiaries, which in turn repeat this process, thereby doubleting the quantity.
• There is also a process in which they form disputes. This happens in the presence of adverse conditions when cytoplasm is able to form, having left the mother shell, a new one, which is more dense. Such a cell is called a dispute. If it falls into a favorable environment, then its germination and the formation of a full -fledged bacterium is possible.

Bacterial propagation time

• Like any phenomenon, division of bacteria It obeys the laws of thermodynamics, according to which the time of reproduction is associated with the amount of heat released outward and is about the sixth part of the heat released.
• Simply put, creating ideal conditions for a bacterium can make a bacterium share Almost every half an hour. If it were possible, during the day, the subsidiaries of one bacteria would reach a mass of almost 2 thousand tons, and in 5 days they would populate the entire water space of the planet.
• It is known that the experience was used sea pseudomonade, placed in optimal conditions: its population doubled after almost 10 minutes.

Bacteria in human life

• Bacteria influence almost any aspect of life of nature and man. It is they who "work" on the circulation of substances, decomposing and modifying organic substances, contributing to soil -forming processes, purifying water bodies.
• The negative effect on living organisms is exerted by pathogenic bacteria described above - they cause diseases not only in humans, but affect both animals and plants.

• Bacteria are used in pharmacology, Being components of drugs, in the food industry, contributing to the production sour -milk products, leafs, cheeses. The marinating process also does not do without bacteria, like wine craft.

Video: benefits from bacteria and microbes