BACTERIA

BACTERIA, simple unicellular microscopic organisms belonging to the kingdom Prokaryotae (prokaryotes). They do not have a clearly defined nucleus, most of them lack CHLOROPHYLL. Many of them have mobility, swim with the help of whip-like flagella. They reproduce mainly by division. Under unfavorable conditions, many of them are able to conserve inside spores, which are highly resistant due to dense protective shells. Subdivided into aerobic and anaerobic. Although pathogenic bacteria are the cause of most human diseases, many of them are harmless or even beneficial to humans, as they form an important link in FOOD CHAINS; for example, they contribute to the processing of plant and animal tissues, the conversion of nitrogen and sulfur into AMINO ACIDS and other compounds that plants and animals can use. Some bacteria contain chlorophyll and are involved in PHOTOSYNTHESIS. see also ARCHEBACTERIA, EUBACTERIA, PROKARYOTES.

Bacteria exist in three main forms and types: spherical (A), called cocci, rod-shaped (bacilli, B) and spiral (spirilla, C). Cocci occur in the form of lumps (staphylococci, 1), pairs of two (diplococci, 2) or chains (streptococci, 3). Unlike cocci, which are unable to move, bacilli move freely; some of them, called peritrichia, have many flagella (4) and can swim, while monotrichia (5, see the figure below) have only one flagellum Bacilli can also form spores (6) to survive a period of adverse conditions SPIRILLA can corkscrew-shaped, such as the spirochete Leplospira (7), and may be slightly curved, with flagella, such as Spirillum (8). Images are given with magnification x 5000

Bacteria do not have a nucleus; instead, they have a nucleoid (1), a single loop of DNA. It contains genes, chemically encoded programs that determine the structure of bacteria. On average, bacteria have 3,000 genes (for comparison, humans have 100,000). The cytoplasm (2) also contains glycogen granules (food) (3) and ribosomes (4), which give the cytoplasm its granular appearance and serve to produce protein. In many bacteria, it also contains tiny genetic elements called plasmids. Most bacteria, but not all, have rigid protective cell walls (B). They come in two main types. The first type has one thick (10-50 nm) layers. Bacteria with this type of cell are called Gram-positive because they stain bright purple with Gram's stain. Gram-negative bacteria are shown to have thinner walls (1) with an extra layer of proteins and lipids on the outside (2). This cell type does not stain purple. Such a difference in properties is used in medicine. The protective cells of the body recognize bacteria precisely by their walls. The cell membrane (3) surrounds the cytoplasm. It has a thickness of only a few molecules of proteins and lipids and is a barrier by which a living cell controls the entry into and removal of various substances from it. Some bacteria move (C) using flagella (1) that are rotated by a hook (2). The energy for movement is provided by the flow of protons through the cell membrane (3), which sets in motion a disk of protein molecules (4) located in the membrane. A rod (5) connects this protein "rotor" to the hook via another disc (6) which seals the cell wall.

Before effective sanitation systems and the discovery of antibiotics, epidemics of serious diseases caused by bacteria swept through Europe again and again. The symptoms of many bacterial diseases are caused by the action of toxic proteins (called toxins) produced by bacteria. Botulinum toxin, produced by the bacterium Clostridium botulinum (which causes food poisoning), is one of the most powerful poisons known today. Tetanus toxin, produced by the related Clostridium tetani (1), infects deep and contaminated wounds. When a nerve impulse (2) causes tension in a muscle cell, the toxin blocks the relaxing part of the signal and the muscles remain tense (which is why the disease is called tetanus). In developed countries, most killer bacteria are now under control, tuberculosis is rare and diphtheria is not a serious problem. However, in developing countries, bacterial diseases still collect their deadly tribute.

Scientific and technical encyclopedic dictionary.

See what "BACTERIA" is in other dictionaries:

E. coli (Escherichia coli) ... Wikipedia

BACTERIA- BACTERIA. Contents:* General Morphology of Bacteria........6 70 Degeneration of Bacteria................675 Biology of Bacteria......................676 Acidophilic Bacilli ........... 677 Pigment-forming bacteria....... 681 Luminous bacteria..... ....... 682… … Big Medical Encyclopedia

- (from the Greek. bakterion stick), microorganisms with a prokaryotic type of cell structure. Traditionally, B. itself means unicellular or organized groups of rods and cocci, immobile or with flagella, opposing ... ... Biological encyclopedic dictionary

- (from the Greek bakterion bacillus) a group of microscopic, predominantly unicellular organisms. They belong to the pre-nuclear forms of prokaryotes. The basis of the modern classification of bacteria, according to which all bacteria are divided into eubacteria (gram-negative ... ... Big Encyclopedic Dictionary

Group of unicellular microscope, organisms. Together with blue-green algae B. represent the kingdom and super kingdom of prokaryotes (see), to a swarm it consists of types (departments) of photobacteria (photosynthetic) and scotobacteria (chemosynthetic). Type… … Dictionary of microbiology

- (from the Greek. bakteria stick). Microscopic single-celled organisms, mostly rod-shaped. Dictionary of foreign words included in the Russian language. Chudinov A.N., 1910. BACTERIA Greek, from bakteria, stick. The genus of palivochny ... ... Dictionary of foreign words of the Russian language

Modern Encyclopedia

bacteria- microorganisms with a prokaryotic type of cell structure, i.e. there is no nuclear membrane, a real nucleus; die from exposure to sunlight; have a sense of smell. cocci are spherical bacteria. diplococci. micrococci. streptococci. staphylococcus. ... ... Ideographic Dictionary of the Russian Language

bacteria- (from the Greek bakterion bacillus), a group of microscopic predominantly unicellular organisms. They have a cell wall, but do not have a well-defined nucleus. They reproduce by division. The shape of the cells of bacteria can be spherical (cocci), ... ... Illustrated Encyclopedic Dictionary

- (from the Greek. bakterion stick), a group of microscopic unicellular organisms. According to the type of respiration, they are divided into aerobic and anaerobic, according to the type of nutrition, into autotrophic and heterotrophic. Participate in the cycle of substances in nature, performing the function ... ... Ecological dictionary

Bacteria are very small, incredibly ancient, and to some extent quite simple microorganisms. According to the modern classification, they were identified as a separate domain of organisms, which indicates a significant difference between bacteria and other life forms.

Bacteria are the most common and, accordingly, the most numerous living organisms, they are, without exaggeration, ubiquitous and feel great in any environment: water, air, earth, as well as inside other organisms. So in one drop of water, their number can reach several million, and in the human body there are about ten more of them than all of our cells.

Who are bacteria?

These are microscopic, predominantly unicellular organisms, the main difference of which is the absence of a cell nucleus. The basis of the cell, the cytoplasm, contains ribosomes and a nucleoid, which is the genetic material of bacteria. All this is separated from the outside world by a cytoplasmic membrane or plasmalemma, which in turn is covered with a cell wall and a denser capsule. Some types of bacteria have external flagella, their number and size can vary greatly, but the purpose is always the same - with their help, the bacteria move.

Structure and contents of a bacterial cell

What are bacteria?

Shapes and sizes

The shapes of different types of bacteria are very variable: they can be round, rod-shaped, convoluted, stellate, tetrahedral, cubic, C- or O-shaped, and also irregular.

Bacteria vary greatly in size. So, Mycoplasma mycoides - the smallest species in the whole kingdom has a length of 0.1 - 0.25 micrometers, and the largest bacterium Thiomargarita namibiensis reaches 0.75 mm - it can even be seen with the naked eye. On average, the sizes range from 0.5 to 5 microns.

Metabolism or metabolism

In matters of obtaining energy and nutrients, bacteria exhibit extreme diversity. But at the same time, it is quite easy to generalize them, dividing them into several groups.

According to the method of obtaining nutrients (carbons), bacteria are divided into:

• autotrophs- organisms capable of independently synthesizing all the organic substances they need for life;
• heterotrophs- organisms that are able to transform only ready-made organic compounds, and therefore need the help of other organisms that would produce these substances for them.

By way of obtaining energy:

• phototrophs organisms that produce energy through photosynthesis
• chemotrophs- Organisms that produce energy through various chemical reactions.

How do bacteria reproduce?

Growth and reproduction in bacteria are closely related. Having reached a certain size, they begin to multiply. In most types of bacteria, this process can proceed extremely quickly. Cell division, for example, can take place in less than 10 minutes, while the number of new bacteria will grow exponentially, since each new organism will be divided into two.

There are 3 different types of reproduction:

• division- one bacterium is divided into two absolutely genetically identical.
• budding- one or more buds (up to 4) are formed at the poles of the parent bacterium, while the mother cell ages and dies.
• primitive sexual process- part of the DNA of the parent cells is transferred to the daughter, and a bacterium appears with a fundamentally new set of genes.

The first type is the most common and fastest, the last one is incredibly important, not only for bacteria, but for all life in general.

The oldest living organism on our planet. Its representatives not only survived for billions of years, but also have enough power to destroy all other species on Earth. In this article, we will look at what bacteria are.

Let's talk about their structure, functions, and also name some useful and harmful types.

Discovery of bacteria

Let's start our tour of the microbial kingdom with a definition. What does "bacteria" mean?

The term comes from the ancient Greek word for "stick". It was introduced into the academic lexicon by Christian Ehrenberg. These are non-nuclear microorganisms, and do not have a nucleus. Previously, they were also called "prokaryotes" (non-nuclear). But in 1970 there was a division into archaea and eubacteria. However, so far more often this concept means all prokaryotes.

The science of bacteriology studies what bacteria are. Scientists say that about ten thousand different types of these living creatures have been discovered so far. However, it is believed that there are more than a million varieties.

Anton Leeuwenhoek, a Dutch naturalist, microbiologist and fellow of the Royal Society of London, in 1676, in a letter to Great Britain, describes a number of the simplest microorganisms that he discovered. His message shocked the public; a commission was sent from London in order to double-check this data.

After Nehemiah Gru confirmed the information, Leeuwenhoek became a world-famous scientist, a discoverer. But in his notes, he called them "animalcules."

Ehrenberg continued his work. It was this researcher who coined the modern term "bacteria" in 1828.

Microorganisms are also used for military purposes. With the help of various species, deadly is created. For this, not only the bacteria themselves are used, but also the toxins secreted by them.

In a peaceful manner, science uses single-celled organisms for research in the fields of genetics, biochemistry, genetic engineering and molecular biology. With the help of successful experiments, algorithms for the synthesis of vitamins, proteins and other substances necessary for a person were created.

Bacteria are also used in other areas. With the help of microorganisms, ores are enriched and water bodies and soils are cleaned.

Scientists also say that the bacteria that make up the microflora in the human intestine can be called a separate organ with its own tasks and independent functions. According to researchers, there are about one kilogram of these microorganisms inside the body!

In everyday life, we encounter pathogenic bacteria everywhere. According to statistics, the largest number of colonies is on the handles of supermarket carts, followed by computer mice in Internet cafes, and only in third place are the handles of public restrooms.

Beneficial bacteria

Even at school they teach what bacteria are. Grade 3 knows all sorts of cyanobacteria and other unicellular organisms, their structure and reproduction. Now we will talk about the practical side of the issue.

Half a century ago, no one thought about such a question as the state of the microflora in the intestines. Everything was OK. Nutrition is more natural and healthy, a minimum of hormones and antibiotics, less chemical emissions into the environment.

Today, in conditions of poor nutrition, stress, an overabundance of antibiotics, dysbacteriosis and related problems come to the fore. How do doctors propose to deal with this?

One of the main answers is the use of probiotics. This is a special complex that repopulates the human intestines with beneficial bacteria.

Such an intervention can help with such unpleasant moments as food allergies, lactose intolerance, disorders of the gastrointestinal tract and other ailments.

Let's now touch on what beneficial bacteria are, and also learn about their impact on health.

Three types of microorganisms have been studied in the most detail and are widely used for a positive effect on the human body - acidophilus, Bulgarian bacillus and bifidobacteria.

The first two are designed to stimulate the immune system, as well as reduce the growth of some harmful microorganisms like yeast, E. coli, and so on. Bifidobacteria are responsible for the digestion of lactose, the production of certain vitamins, and the reduction of cholesterol.

harmful bacteria

Earlier we talked about what bacteria are. The types and names of the most common beneficial microorganisms were announced above. Further, we will talk about the "unicellular enemies" of man.

There are those that are harmful only to humans, there are deadly to animals or plants. People have learned to use the latter, in particular, to destroy weeds and annoying insects.

Before delving into what are, it is worth deciding on the ways of their distribution. And there are a lot of those. There are microorganisms that are transmitted through contaminated and unwashed products, airborne and contact routes, through water, soil or insect bites.

The worst thing is that just one cell, once in a favorable environment of the human body, is able to multiply up to several million bacteria within just a few hours.

If we talk about what bacteria are, the names of pathogenic and beneficial ones are difficult to distinguish for a non-professional. In science, Latin terms are used to refer to microorganisms. In common speech, abstruse words are replaced by concepts - "E. coli", "causative agents" of cholera, whooping cough, tuberculosis and others.

Preventive measures to prevent the disease are of three types. These are vaccinations and vaccines, interruption of transmission routes (gauze bandages, gloves) and quarantine.

Where do bacteria in urine come from?

Some people try to monitor their health and take tests at the clinic. Very often the cause of poor results is the presence of microorganisms in the samples.

About what bacteria are in the urine, we will talk a little later. Now it is worth dwelling separately on where, in fact, single-celled creatures appear there.

Ideally, a person's urine is sterile. There can be no foreign organisms. The only way for bacteria to enter the secretions is at the site where waste is removed from the body. In particular, in this case it will be the urethra.

If the analysis shows a small number of inclusions of microorganisms in the urine, then everything is normal so far. But with an increase in the indicator above the permitted limits, such data indicate the development of inflammatory processes in the genitourinary system. This may include pyelonephritis, prostatitis, urethritis and other unpleasant ailments.

Thus, the question of what kind of bacteria are in the bladder is completely incorrect. Microorganisms enter the secretions not from this organ. Scientists today identify several reasons leading to the presence of single-celled creatures in the urine.

• First, it is a promiscuous sex life.
• Secondly, diseases of the genitourinary system.
• Thirdly, neglect of the rules of personal hygiene.
• Fourthly, decreased immunity, diabetes and a number of other disorders.

Types of bacteria in urine

Earlier in the article it was said that microorganisms in waste products are found only in case of diseases. We promised to tell you what bacteria are. Names will be given only of those species that are most often found in the results of analyses.

So, let's begin. Lactobacillus is a representative of anaerobic organisms, a gram-positive bacterium. It must be in the human digestive system. The presence of it in the urine indicates some failures. Such an event is uncritical, but it is an unpleasant call to the fact that you should seriously take care of yourself.

The proteus is also a natural inhabitant of the gastrointestinal tract. But the presence of it in the urine indicates a failure in the withdrawal of feces. This microorganism gets from food into urine only in this way. A sign of the presence of a large amount of proteus in the waste is a burning sensation in the lower abdomen and painful urination with a dark color of the liquid.

Very similar to the previous bacterium is Enterococcus fecalis. It enters the urine in the same way, multiplies rapidly and is difficult to treat. In addition, Enterococcus bacteria are resistant to most antibiotics.

Thus, in this article, we figured out what bacteria are. We talked about their structure, reproduction. You have learned the names of some harmful and beneficial species.

Good luck, dear readers! Remember that personal hygiene is the best prevention.

In our world there is a huge number of bacteria. Some of them are good and some are bad. Some we know better, others worse. In our article, we have compiled a list of the most famous bacteria living among us and in our body. The article is written with a share of humor, so do not judge strictly.

Provides "face - control" in your insides

Lactobacilli (Lactobacillus plantarum) living in the human digestive tract since prehistoric times, do a great and important job. Like vampire garlic, they scare away pathogenic bacteria, preventing them from settling in your stomach and upsetting your intestines. welcome! Pickles and tomatoes and sauerkraut will bolster the strength of bouncers, but know that hard training and stress from exercise will shorten their ranks. Add some blackcurrant to your protein shake. These berries reduce fitness stress due to their antioxidant content.

2. PROTECTOR OF THE BELLY Helicobacter pylori

Stop hunger pangs at 3 p.m.

Another bacteria living in the digestive tract, Helicobacter pylori, develops from your childhood and helps you maintain a healthy weight throughout your life by controlling the hormones responsible for feeling hungry! Eat 1 apple every day.

These fruits produce lactic acid in the stomach, in which most harmful bacteria cannot survive, but which Helicobacter pylori adores. However, keep H. pylori within limits, they can work against you and cause stomach ulcers. Make scrambled eggs with spinach for breakfast: the nitrates from these green leaves thicken the walls of the stomach, protecting it from excess lactic acid.

3. Pseudomonas aeruginosa head

Likes showers, hot tubs and pools

The warm-water bacterium Pseudomonas aeruginosa crawls under the scalp through the pores of the hair follicles, causing an infection accompanied by itching and pain in the affected areas.

Don't want to put on a bathing cap every time you take a bath? Fend off a comber intrusion with a chicken or salmon and egg sandwich. A large amount of protein is necessary for the follicles to be healthy and effectively fight foreign bodies. Don't forget about fatty acids, which are absolutely essential for a healthy scalp. This will help you 4 cans of canned tuna or 4 medium avocados per week. No more.

4. Harmful bacteria Corynebacterium minutissimum

High tech protozoan

Harmful bacteria can lurk in the most unexpected places. For example, Corynebacterium minutissimum, which causes a rash, loves to live on the touchscreens of phones and tablet computers. Destroy them!

Strangely, no one has yet developed a free application that fights these germs. But many companies produce cases for phones and tablets with an antibacterial coating, which is guaranteed to stop the growth of bacteria. And try not to rub your hands together when you dry them after washing - it can reduce the bacteria population by 37%.

5. NOBLE CRAUNT Escherichia coli

Good bad bacteria

The bacterium Escherichia coli is believed to cause tens of thousands of infectious diseases every year. But it only gives us problems when it finds a way to leave the colon and mutate into a disease-causing strain. Normally, it is quite useful for life and provides the body with vitamin K, which maintains the health of the arteries, preventing heart attacks.

To keep this headline bacterium in check, include legumes in your diet five times a week. The fiber in the beans is not broken down, but moves to the large intestine, where E. coli can feast on it and continue their normal reproductive cycle. Black beans are the richest in fiber, then Ithlim, or moon-shaped, and only then is the usual red bean that we are used to. Legumes not only keep bacteria in check, but also limit your afternoon appetite with their fiber, and increase the efficiency of the absorption of nutrients by the body.

6. BURNING Staphylococcusaureus

Eats the youth of your skin

Most often, boils and pimples are caused by the bacterium Staphylococcusaureus, which lives on the skin of most people. Acne is, of course, unpleasant, but, having penetrated through damaged skin into the body, this bacterium can cause more serious diseases: pneumonia and meningitis.

The natural antibiotic dermicidin, which is toxic to these bacteria, is found in human sweat. At least once a week, include high-intensity exercises in your workout, trying to work at 85% of your maximum capacity. And always use a clean towel.

7. MICROBE - BURNER Bifidobacterium animalis

® Lives in fermented milk products

Bifidobacterium animalis bacteria inhabit the contents of cans of yogurt, bottles of kefir, curdled milk, fermented baked milk and other similar products. They reduce the time of passage of food through the colon by 21%. Food does not stagnate, there is no formation of excess gases - you are less likely to experience the problem code-named "Feast of the Spirit."

Feed the bacteria, for example, with a banana - eat it after dinner. And for lunch itself, pasta with artichokes and garlic will go well. All these products are rich in fructooligos - saccharides - Bifidobacterium animalis loves this type of carbohydrate and eats them with pleasure, after which it multiplies with no less pleasure. And as the population grows, your chances of normal digestion increase.

We try to provide the most relevant and useful information for you and your health. The materials posted on this page are for informational purposes and are intended for educational purposes. Site visitors should not use them as medical advice. Determining the diagnosis and choosing a treatment method remains the exclusive prerogative of your doctor! We are not responsible for possible negative consequences resulting from the use of information posted on the website.

To understand the importance of bacteria, it is enough to know that they arose about 3.5 billion years ago and that it is the bacteria that prepare the nutrient solutions that both animals and plants feed on!

BACTERIA, an extensive group of unicellular microorganisms characterized by the absence of an enveloped cell nucleus. At the same time, the genetic material of a bacterium (deoxyribonucleic acid, or DNA) occupies a very specific place in the cell - a zone called the nucleoid. Organisms with this cell structure are called prokaryotes (“pre-nuclear”), in contrast to all the others - eukaryotes (“true nuclear”), whose DNA is located in the nucleus surrounded by a shell.

Bacteria, once considered microscopic plants, are now classified as a separate kingdom, Monera, one of five in the current classification system, along with plants, animals, fungi, and protists.

fossil evidence.

Bacteria are probably the oldest known group of organisms. Layered stone structures - stromatolites - dated in some cases to the beginning of the Archeozoic (Archaean), i.e. that arose 3.5 billion years ago, is the result of the vital activity of bacteria, usually photosynthetic, the so-called. blue-green algae.

Similar structures (bacterial films impregnated with carbonates) are formed now, mainly off the coast of Australia, the Bahamas, in the California and Persian Gulfs, but they are relatively rare and do not reach large sizes, because herbivorous organisms, such as gastropods, feed on them.

Today, stromatolites grow mainly where these animals are absent due to the high salinity of the water or for other reasons, but before the appearance of herbivorous forms in the course of evolution, they could reach enormous sizes, constituting an essential element of oceanic shallow water, comparable to modern coral reefs.

Tiny charred spheres have been found in some ancient rocks, which are also thought to be the remains of bacteria. The first nuclear, i.e. eukaryotic, cells evolved from bacteria about 1.4 billion years ago.

Ecology.

There are many bacteria in the soil, at the bottom of lakes and oceans - everywhere where organic matter accumulates. They live in the cold, when the thermometer is slightly above zero, and in hot acidic springs with temperatures above 90 ° C.

Some bacteria tolerate very high salinity; in particular, they are the only organisms found in the Dead Sea. In the atmosphere, they are present in water droplets, and their abundance there usually correlates with the dustiness of the air.

So, in cities, rainwater contains much more bacteria than in rural areas. There are few of them in the cold air of the highlands and polar regions; nevertheless, they are found even in the lower layer of the stratosphere at an altitude of 8 km.

The digestive tract of animals is densely populated with bacteria (usually harmless). Experiments have shown that they are not necessary for the life of most species, although they can synthesize some vitamins.

However, in ruminants (cows, antelopes, sheep) and many termites, they are involved in the digestion of plant foods. In addition, the immune system of an animal raised in sterile conditions does not develop normally due to the lack of stimulation by bacteria. The normal bacterial "flora" of the intestine is also important for the suppression of harmful microorganisms that enter there.

STRUCTURE AND LIFE OF BACTERIA

Bacteria are much smaller than the cells of multicellular plants and animals. Their thickness is usually 0.5–2.0 µm, and their length is 1.0–8.0 µm.

Some forms can barely be seen with the resolution of standard light microscopes (about 0.3 µm), but there are also known species with a length of more than 10 µm and a width that also goes beyond these limits, and a number of very thin bacteria can exceed 50 µm in length.

A quarter of a million medium-sized representatives of this kingdom will fit on the surface corresponding to the point set with a pencil.

Structure.

According to the peculiarities of morphology, the following groups of bacteria are distinguished: cocci (more or less spherical), bacilli (rods or cylinders with rounded ends), spirilla (rigid spirals) and spirochetes (thin and flexible hair-like forms). Some authors tend to combine the last two groups into one - spirilla.

Prokaryotes differ from eukaryotes mainly in the absence of a well-formed nucleus and the presence, in a typical case, of only one chromosome - a very long circular DNA molecule attached at one point to the cell membrane.

Prokaryotes also lack membrane-bound intracellular organelles called mitochondria and chloroplasts. In eukaryotes, mitochondria produce energy during respiration, and photosynthesis takes place in chloroplasts (see also CELL). In prokaryotes, the entire cell (and, first of all, the cell membrane) takes on the function of the mitochondria, and in photosynthetic forms, at the same time, the chloroplast.

Like eukaryotes, inside the bacterium are small nucleoprotein structures - ribosomes necessary for protein synthesis, but they are not associated with any membranes. With very few exceptions, bacteria are unable to synthesize sterols, which are important components of eukaryotic cell membranes.

Outside of the cell membrane, most bacteria are lined with a cell wall, somewhat reminiscent of the cellulose wall of plant cells, but consisting of other polymers (they include not only carbohydrates, but also amino acids and substances specific to bacteria).

This shell prevents the bacterial cell from bursting when water enters it due to osmosis. On top of the cell wall is often a protective mucosal capsule.

Many bacteria are equipped with flagella, with which they actively swim. Bacterial flagella are simpler and somewhat different than similar eukaryotic structures.

Sensory functions and behavior.

Many bacteria have chemical receptors that detect changes in the acidity of the environment and the concentration of various substances, such as sugars, amino acids, oxygen and carbon dioxide.

Each substance has its own type of such “taste” receptors, and the loss of one of them as a result of mutation leads to partial “taste blindness”.

Many motile bacteria also respond to temperature fluctuations, and photosynthetic species to changes in light.

Some bacteria perceive the direction of magnetic field lines, including the Earth's magnetic field, with the help of magnetite particles (magnetic iron ore - Fe 3 O 4) present in their cells.

In water, bacteria use this ability to swim along lines of force in search of a favorable environment.

Conditioned reflexes in bacteria are unknown, but they have a certain kind of primitive memory. While swimming, they compare the perceived intensity of the stimulus with its previous value, i.e. determine whether it has become larger or smaller, and, based on this, maintain the direction of movement or change it.

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