Bacteria in nature and in life are negative. The meaning of bacteria. Participation in food chains

When you hear the word “bacteria,” the first thing that comes to mind is the terrible microbes that are responsible for almost everything – from the common flu to cancer as a consequence of the disease. So what is the true significance of bacteria in nature and human life? Let's start with the fact that bacteria, according to the as yet unrefuted opinion of scientists, were the first organisms to appear on our planet. And if these “discoverers” had not released oxygen, poor humanity would have had no chance of survival. Even more, if bacteria had not bothered to create protein as such, then the existence of protein life (including you and me) could be safely forgotten!

If you believe the official version of history, bacteria appeared on Earth several billion years ago, and then for about another billion years no one stopped them from enjoying life in splendid isolation. In comparison with the history of mankind, which dates back some hundreds of thousands of years, this is an enormous period of time. During this time, microorganisms learned to adapt to the environment, changing their structure, and change the environment, adapting it to their needs.

The vitality of bacteria is incomparable, perhaps, with any living organism on Earth. They live:

• in the ocean depths under monstrous pressure;
• in arctic cold conditions, and retain the ability to exist after defrosting;
• in hot springs at temperatures of a hundred degrees (and even more!);
• in the human stomach, resisting the action of hydrochloric acid;
• in the vents of underwater volcanoes, where three (at least) aggressive factors converge simultaneously - temperature, pressure, toxic gases;
• in the upper rarefied layers of the atmosphere, where it is already closer to cosmic cold than to the warm earth;
• deep underground they survive by snacking on sulfur compounds and washing down their lunch with oil, etc.

In a word, there is no corner on our planet and in our body where bacteria do not live. There is a theory that life appeared on Earth along with bacteria that arrived to us inside some fateful meteorite. This means that microorganisms managed to survive in absolute vacuum and space cold! And they not only survived, but retained the ability to reproduce, populated the entire planet, prepared the ground for the emergence of fungi and algae, which led to an increase in the diversity of life in nature and, as a result, to the emergence of humanity! And this is only the beginning of the answer to the question of what is the importance of bacteria in nature and in human life. In short, without them we wouldn’t exist.

So who are they, bacteria?

In the second half of the 19th century, a new direction in science was formed - microbiology. This science appeared as a branch of medicine and studied the role of bacteria as pathogens. The founders of microbiology were Pascal, Mechnikov, Koch, Ehrlich and other doctors who were able to consider the connection between tiny creatures and human diseases. Modern microbiology deals not only with medical problems, it plays a large role in industry (biotechnology) and in a relatively new branch of science - genetic engineering.

Microorganisms (or microbes) are considered to be all living organisms that cannot be seen with the naked eye (without a microscope). In nature there are three domains (regions):

• viruses;
• protozoa and fungi;
• true bacteria.

Bacteria differ from other domains in their structure - they do not have a nucleus bounded by a membrane. Instead, they have a DNA molecule closed in a loop, which takes on the role of transferring genetic information from the mother cell to the daughter cell.

Bacteria are single-celled organisms with the simplest structure:

• outer layer – cell wall;
• thin inner layer - cytoplasmic membrane;
• internal gel-like substance - cytoplasm;
• the prototype of the nucleus (DNA molecule) is a nucleoid;
• “spare” information storage facilities (RNA molecules) – ribosomes.

These are just the basic structures of a bacterial cell. Additional ones that appear depending on the functions of the cell or the conditions of its existence include capsules, pili, spores, plasmids, volutin grains and other devices developed over billions of years of evolution for the survival of bacteria as a species.

What will we eat...

The further the study of bacteria progressed, the more interesting the picture emerged. It turned out that the soil that feeds us all was also formed thanks to microorganisms. However, water and air played an important role. But the beginning was made precisely by bacteria.

Further more. Organic substances used by plants are also created by microorganisms (bacteria - producers). Moreover, they use inorganic compounds for this, and take energy from the reactions of photo- and chemosynthesis, i.e. from sunlight and chemical transformations. But it’s not enough to create organic matter; you also need to do something with the dead remains. Otherwise, the planet would have long ago turned into a waste food cemetery (to put it mildly). Nature has assigned the same ubiquitous bacteria to the role of scavengers.

Some bacteria (reducers or saprophytes) use waste organic residues and dead cells as food, decomposing them into simple and inorganic substances, which are then put back into use.

This way the circle is closed and nothing is wasted. The totality of transformations of the chemical elements that make up all living beings is called the cycle of substances. This is a fundamental rule of nature, and it would be impossible to implement without the help of such a tiny and, at first glance, defenseless cell.

...and what to breathe

The first reserves of oxygen on our planet also appeared thanks to bacteria. This sounds quite strange, but oxygen is just a by-product of the nutrition of photosynthetic microorganisms (phototrophs), so to speak, a waste product.

Animals and humans also play a role in maintaining the balance of the atmosphere. The process of photosynthesis requires carbon dioxide, and it is precisely this that is released during respiration and during the combustion process (remember our plants, factories and cars). The circle is closed again and there are clear advantages of the existence of a balanced system.

Another, no less necessary element is nitrogen. It is necessarily part of proteins and nucleic acids, that is, it forms the basis of protein life. Animals and humans obtain this element from foods rich in protein. It can be of plant or animal origin. Animals take protein from plants, but how is it formed in the plants themselves?

There's a slight problem here. There is quite a lot of nitrogen in the atmosphere of our planet (78% of the total volume), but plants cannot absorb it from the air on their own. The soil also contains nitrogen, but very little and often in compounds that are not suitable for plant food. As usual, our little friends come to the rescue. There is a special breed of bacteria (nitrogen-fixing) that convert nitrogen compounds into nitrates, available to plants.

So, the soil is ready, the atmosphere is created, the basis for protein life is there. After the preparatory work carried out by bacteria, fungi, algae and protozoa appear, increasing the diversity of life and hastening our appearance on Earth.

The basis of life

The structure of a bacterial cell contains ribosomes (ribonucleoprotein particles). They are responsible for protein synthesis. There can be up to 90 thousand such small pieces in a cell! This shows how important ribosomes are to nature. What is their importance?

The role of ribosomes is the synthesis of protein from amino acids. The sequence of the process is recorded in RNA genetic information (not DNA!). But the catch is this: DNA cannot reproduce itself; it needs a catalyst (trigger), which is a protein. And protein, in turn, cannot be formed without DNA. A chicken and egg paradox arises.

It turned out that RNA (ribonucleic acid), which forms the basis of ribosomes, easily copes with all this. It transmits information, works as a catalyst and transports amino acids, producing at the output that very valuable protein, the basis of our life.

These findings formed the basis of the theory of life “before DNA.” Who knows, maybe after some time scientists will have to reconsider the theory of the origin of life on Earth?

Human + bacteria = symbiotic system

A person cannot survive without his bacteria, just as bacteria cannot survive without a person. This symbiotic system was formed over a huge amount of time, and an improved and thoroughly tested version has survived to this day.

The total weight of bacteria in the human body is about four kilograms. About two of them occur in the gastrointestinal tract. Bacteria cover our body with a kind of invisible cloak, making up the normal human microflora. Everyone has their own, its main role is to protect a person from extraneous “invading” bacteria (if the immune system is in order), killing them or depriving them of food.

By the way, bacteria living in the gastrointestinal tract play a huge role in the formation and maintenance of the immune system. If you treat them with due respect and do not poison them with harmful food and toxins, then the result will not be long in coming.

Digestion in the human body is impossible without bacteria living in the intestines (not to be confused with the stomach). These microorganisms produce vitamins and enzymes, without which our body will not be able to absorb even the freshest and healthiest food. Oddly enough, one of these bacteria is E. coli, the same one that is responsible for many dangerous diseases. It's all about proportions. As long as the amount of E. coli is normal, a person feels great, but as soon as suitable conditions are created for it, it will seize power and loudly declare itself.

Not only E. coli, but also many other bacteria, called opportunistic bacteria, exist in the human body without causing harm until a certain time. The trigger mechanism can be a decrease in immunity (injury, illness), poor lifestyle, bad habits, stress.

Not everything is so rosy

Now a little about the cons. Bacteria are not always pink and fluffy. It is to them that we owe many diseases, and until we learned to detect them and somehow fight them, even the most terrible epidemics, such as smallpox, plague or cholera.

The recently discovered bacterium Helicobacter pylori lives in the stomach of more than half of humanity. The scientists who proved the guilt of this “criminal” in intestinal diseases (ulcers, gastritis) were even awarded the Nobel Prize, this research was so important.

And just the other day, information appeared that in the stomach (or rather, its remains) of the famous Tyrolean ice man Ötzi (a mummy found in the Alps in 1991), who lived 5,300 years ago, traces of Helicobacter DNA were found. Nowadays, several strains of this bacterium are distinguished, each tied to its own region: African, Asian and a hybrid of these two - European. It turned out that the strain of bacteria in Ötzi’s body was of Asian origin, although it should have been European. The discovery calls into question the history of the settlement of Europe and the time frame for the settlement of peoples.

How do viruses differ from bacteria?

It turns out that bacteria not only took care of creating life on our planet, they continue to actively care for humanity, forcing them to take care of their health and maintain balance in nature. In an effort to survive themselves, they help the survival of humanity. And even when people decide to go into space, bacteria will follow them.

These are primitive single-celled living organisms. They are distributed everywhere: on the surface or inside other organisms (animals, plants, humans), and are found in large quantities in soil and water bodies. Directly or indirectly, bacteria play an important role in human life.

One of the living environments of bacteria is other living organisms, including humans. The relationships that arise in this case may be different. There are bacteria that are beneficial. Thus, bacteria live in the human intestine (for example, E. coli), which promote digestion processes, synthesize some vitamins and prevent the activity of pathogenic bacteria. If you take antibacterial drugs excessively, these beneficial bacteria are killed, which negatively affects your health. The E. coli itself, thanks to its settlement in the human intestine, is constantly provided with nutrients.

Bacteria also live in the intestines of domestic ruminants, which form the basis of livestock farming (cows, goats, sheep). Ruminant animals consume plant foods rich in fiber, but are not able to digest fiber on their own. This function is performed by bacteria.

Pathogenic bacteria can also be carried by blood-sucking insects. Thus, the causative agent of plague is carried by fleas, and typhus is carried by lice.

In humans, bacteria cause diseases such as sore throat, diphtheria, tuberculosis, typhus, dysentery, cholera, and many others; in animals - brucellosis, anthrax, etc. Bacterial diseases are treated with antibiotics and other medications.

Bacteria are widely used in human agriculture. Thus, since ancient times, people have used the ability of certain bacteria to cause fermentation to produce certain products: lactic acid products (yogurt, cheese, kefir), butyric and acetic acids, etc. Without bacteria, leather tanning and flax fiber production are impossible.

Certain groups of bacteria are also used in the microbiological industry to produce antibiotics, vitamins and some other substances. In agriculture they are used for ensiling green fodder.

One of the important problems of our time is wastewater treatment. Sewage treatment plants use bacteria that decompose organic residues. In addition, by studying the number and species composition of bacteria in water, the degree of pollution of water bodies can be determined. With the help of certain bacteria, humans fight blood-sucking animals and agricultural and forestry pests. Special bacterial preparations have been invented that affect only certain types of harmful bacteria.

Bacteria can harm human economic activities, for example, spoil food. At the same time, bacteria produce toxic substances that can poison the body of a person or animal if they eat spoiled foods. For example, botulism bacillus can develop in canned meat and vegetable products, fish, and sausage, if strict rules of the technological process are not followed during canning. To completely get rid of bacteria in food products intended for long-term storage, they are sterilized or pasteurized.

There are a huge number of living organisms in the world. Each of them is unique in its own way. But there are such amazing species that directly affect human life and nature itself. They are called bacteria. A bacterium is a single-celled microorganism. Today, over ten thousand different species of bacteria have been discovered, and their number is approximately more than one million. Like many microorganisms, bacteria are good and bad.

In the natural system, these microorganisms play an important role. They live in the upper layer of the earth, destroying organic compounds (remains of dead living and plant organisms). They are engaged in cleansing the earth from decaying products of biological activity, converting organic substances into inorganic ones. The Tokay process supports the biological cycle of chemical elements. Some of the most important microorganisms are those that are capable of nitrogen fixation. This is a process by which nitrogen in the air is fixed and converted into a form more suitable for plant absorption. This process is important for plants that need nitrogen to live. This ability is possessed by nodule bacteria that are found in the roots of leguminous plants.

Bacteria play a huge role for humans. They live both outside and inside the body. They spoil food and speed up its shelf life. To avoid this, people subject food products to various processing methods: boiling, sterilization, freezing, pasteurization. Food that has been damaged by bacteria can lead to food poisoning. There are also types of bacteria that cause various diseases in humans: typhoid fever, whooping cough, tetanus, tuberculosis. They can be transmitted by insects, dirt on a wound, or through airborne transmission (person-to-person saliva, kissing, coughing, or sneezing)

However, despite this, there are also good (useful) bacteria. Inside the body, they promote improved digestion of food and break down complex substances into simpler ones for rapid absorption by the body. Bacteria are also used to create various antibiotics and medicines, to prepare fermented milk products, wine and other similar things. For example, kefir, fermented baked milk and yoghurts are produced by adding good bacteria to milk, which oxidize dairy products by producing residues of their vital activity.

Bacteria play an important role in human life and nature. However, it is worth remembering that bacteria, in any case, are dangerous microorganisms that can infect a person with illness and disease, and in some cases even kill. You should remember about the various methods of defense against invisible enemies. Be sure to wash your hands thoroughly with soap, as soap has a structure that can remove bacteria from human skin. It should also be remembered that bacteria also live on food, so they should also be washed and subjected to various treatments. If the body has been attacked by bacteria, then first of all you need to contact a qualified specialist and follow his instructions.

Option 2

Microorganisms are widespread in nature. These include a wide variety of morphological and physiological features of the plant and animal world - bacteria, fungi, actinomycetes, rickettsia, viruses and protozoa. Some of them are permanent inhabitants of soil and water, where they play an important role in the range of substances. Other microorganisms have evolved to live with human, plant and animal organisms. The relationships that arise between microorganisms and macroorganisms are too complex.

There are a large number of microorganisms in the human skin and mucous membranes, in the oral cavity and digestive tract. Some of them are permanent residents of the body, while others are temporarily present there.

The permanent inhabitants of the human body constitute its normal microflora. They play an important role as a defense mechanism and natural resistance.

In damaged physiological defense mechanisms of the macroorganism against infectious or non-infectious diseases, these bacteria can adversely affect the inhabitants of the body and harm them, becoming harmful to the cause of infections.

A bacterial cell has only one ring-shaped chromosome. Because it is so thin, long and folded, with a light microscope the chromosome is not visible as a thread, but simply as a “cloud” in the middle of the cell. We can compare it to braided yarn. But the bacterial chromosome only appears tangled. In fact, any part is available for work if necessary. Some bacteria, called bacilli, may experience unfavorable conditions as they adopt a more resilient lifestyle. Their cell is usually rod-shaped, but if necessary, it is compressed into a small ball and wrapped in an additional shell. This form of bacilli, called a spore, does not need food because it has a very slow metabolism. When conditions become favorable again, the spore turns back into a stick.

Microbiology is a relatively young science that has developed over the past century and studies life, human development, and the nature of small single-celled animals and plants called microorganisms (microbes). They can only be observed under a microscope. The term "microbe" was first used in 1878.

Message 3

Bacteria are a division of prokaryotic organisms. They are single-celled with spherical, straight or curved spiral and other cells. Bacteria are one of the smallest organisms, most often ranging from 0.001 to 0.005 mm. About 1,500 species are known throughout the world.

They have a cell wall that has a characteristic composition and structure. They do not have a single nucleus or organelles bounded by a cytomembrane. Their ribosomes are smaller than those of eukaryotic organisms.

Bacteria are among the most ancient organisms, the remains of which were discovered in layers about 3,200 million years ago. The closest relatives are blue-green algae.

Bacteria are widespread. Their small size and relatively large surface are a prerequisite for intensive metabolism. Therefore, due to their ability to carry out various processes (fermentation, decomposition, extraction of free nitrogen, mineralization of nitrogenous substances, etc.), bacteria are of great importance in the biosphere and for humans. Their great ability to reproduce (in some types of cells division occurs every 20 minutes) contributes to a rapid increase in the number of bacteria (in soils up to 100 million cells per 1 g, in dirty water up to 10 billion, but in drinking water there are no more than 50).

Bacteria are distributed throughout the world. They live and reproduce in soil, in sweet and salty waters, in rock holes, on larger organisms and even inside their bodies. In the air, bacteria cannot actively move and multiply, but attach to dust or microscopic droplets. In some types of bacteria, cumulative cells are closely related to each other. They can even help each other, some of them specialize in one vital function, others in another, and, in the end, each cell takes advantage of all the skills. Such clusters of cells are called colonies, and the species is colonial. A colony is an intermediate stage from a single cell to a multicellular organization.