Organisms that do not have a formalized nucleus belong to. Organisms consisting of one cell and not having a formalized nucleus are

Bacteria is a concept that everyone is familiar with. They are found everywhere, each habitat is literally inhabited by billions of varieties: in salt water, fresh water, on the surface of hot springs, glaciers and organisms of living beings. Bacteria are representatives of the unicellular category used for the chemical, medical, and food industries. In addition to these organisms, representatives of the kingdom of protozoa are:

plants (many types of green algae);
animals;
most mushrooms.

Microscopic cells do not belong to eukaryotes, since they do not have a formed nucleus. Other categories of unicellular plants, fungi, and animals are similar to each other in the presence of this main cellular component.

The unicellular structures of bacteria (prokaryotes) also lack additional membrane organelles. There are differences, for example, in cyanobacteria that perform a photosynthetic function - flat tanks.

It is a mistake to assume that representatives of the unicellular kingdom have the same structure. The differences are not global, but they exist. All the nuances of the structure of organisms related to prokaryotes or eukaryotes can be seen in the photo taken under a microscope. You can consider colonies of unicellular bacteria, as well as the specifics of their cell structure.

Representatives of the plant kingdom - algae - choose water bodies with different composition of the liquid medium as their habitat. The main difference between them and bacteria is the absence of a formed nucleus in the latter. In algae, hereditary information is stored there, ribonucleic acid (RNA) is synthesized.

Unicellular organisms of some bacteria have a protective capsule that allows protecting the cell from mechanical damage during movement, drying (depending on the specific conditions of its life). It is also a source of reserve substances, allowing them not to die (it is absent in plants). The difference from algae is also the presence of plasmids in bacteria. These are the keepers of genomic information, which makes it possible to actively fight against antibiotics that destroy the structure of the cell.

When comparing bacteria with unicellular algae, the following common components can be noted:

cytoplasm (it contains organelles, nutrients are evenly distributed throughout the cell),
ribosomes (organelles for protein synthesis in unicellular organisms),
cytoskeleton (musculoskeletal formation inside the cell; not all bacteria contain it),
flagella (serve to move in space).

Usually, algae organelles are viewed in detail under a microscope. Algae organisms have mitochondria, the main function of which is to ATP synthesis, a compound that plays a primary role in the metabolism of energy and substances in plants (these organelles are shown in the photo).

How are fungi different from bacteria?

All types of fungi have a well-shaped nucleus, the cell wall is formed by chitin (in bacteria it is murein or pectin). The cell contains DNA, histone, proteins. The photo shows the results of a study of a bacterial cell, in which instead of a nucleus there is a nucleoid - an irregularly shaped nuclear region containing genetic material.

Bacteria are the simplest unicellular, which belong to the category of saprotrophs, as representatives of the kingdom of fungi. All organisms usually have a cell membrane that performs a number of important functions (energy, transport, barrier, protective). They also differ in structure.

Mushrooms differ in the presence of contacts between cells. Fungi have septa designed to transport nutrients between cells, while bacterial organisms do not differ in such capabilities.

Mushrooms are divided into three categories based on their mode of nutrition:

This is their main similarity with bacteria.

Saprotrophs (this includes fungal cells, the kingdom of green algae to this species not applicable) are microscopic organisms capable of actively extracting nutrients from organic material dominated by dead elements. In the photo you can see examples of mushrooms with multiple magnification.

Organisms of unicellular animals: specifics

This is a huge class that has many subspecies that can reproduce sexually or asexually. Unicellular organisms are represented by more than 30 thousand animal organisms, between which there are similar and different features. The body of protozoa consists of a nucleus and cytoplasm; they do not have a protective capsule, plasmids, or cell wall.

As representatives of green algae, they have chromosomes and formalized DNA. The category of green algae is predominantly prone to photosynthesis, animal organisms, for example, green euglena (shown in the photo) have chloroplasts, in the dark they can absorb organic matter, even absorb bacteria.

Varieties of unicellular bacteria

All microscopic organisms (except fungi) can have flagella, allowing them to move freely in space. In the photo you can see the organelles that are used by plants for an active "lifestyle". Below is a table that allows you to understand the main differences between the unicellular kingdoms and what components are present in their structure.

There are many types of microorganisms, each of which differs in shape and structure. It, in turn, depends on the nutrition of the body and the way it lives. Distinguish: cocci (round), vibrios and spirochetes (tortuous type), bacilli and clostridia (rods). In the photo you can see all these varieties, but the organisms are similar in structure.

Each difference is due to many factors, including the evolution of categories of microorganisms. For example, animals are more adapted to survival, bacteria can develop resistance to aggressive components such as antibiotics, algae contain almost the entire complex of organelles necessary for survival.

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Eukaryotes are the most advanced organisms. In our article, we will consider which of the representatives of wildlife belong to this group and what features of the organization allowed them to occupy a dominant position in the organic world.

Who are eukaryotes

According to the definition of the concept, eukaryotes are organisms whose cells contain a formed nucleus. These include the following kingdoms: Plants, Animals, Mushrooms. And it doesn't matter how complex their body is. Microscopic amoeba, Volvox colonies, they are all eukaryotes.

Although the cells of real tissues can sometimes be devoid of a nucleus. For example, it is not present in erythrocytes. Instead, this blood cell contains hemoglobin, which carries oxygen and carbon dioxide. Such cells contain a nucleus only at the first stages of their development. Then this organelle is destroyed, and at the same time the ability of the entire structure to divide is lost. Therefore, having performed their functions, such cells die.

The structure of eukaryotes

All eukaryotic cells have a nucleus. And sometimes not even one. This two-membrane organelle contains in its matrix genetic information encrypted in the form of DNA molecules. The nucleus consists of a surface apparatus that provides the transport of substances, and a matrix - its internal environment. The main function of this structure is to store hereditary information and its transmission to daughter cells resulting from division.

The internal environment of the kernel is represented by several components. First of all, it is karyoplasm. It contains the nucleoli and chromatin strands. The latter are composed of proteins and nucleic acids. It is during their spiralization that chromosomes are formed. They are directly carriers of genetic information. Eukaryotes are organisms in which, in some cases, two types of nuclei can form: vegetative and generative. A striking example of this is infusoria. Its generative nuclei carry out the preservation and transmission of the genotype, and the vegetative nuclei regulate

The main differences between pro- and eukaryotes

Prokaryotes do not have a well-formed nucleus. This group of organisms includes only one - Bacteria. But such a feature of the structure does not mean at all that there are no carriers of genetic information in the cells of these organisms. Bacteria contain circular DNA molecules - plasmids. However, they are located in the form of clusters in a certain place in the cytoplasm and do not have a common shell. This structure is called a nucleoid. There is one more difference. DNA in prokaryotic cells is not associated with nuclear proteins. Scientists have established the existence of plasmids in eukaryotic cells. They are found in some semi-autonomous organelles, such as plastids and mitochondria.

progressive building features

Eukaryotes include organisms that differ in more complex structural features at all levels of organization. First of all, this concerns the method of reproduction. provides the simplest of them - in two. Eukaryotes are organisms that are capable of all types of reproduction of their own kind: sexual and asexual, parthenogenesis, conjugation. This ensures the exchange of genetic information, the appearance and fixation of a number of useful traits in the genotype, and hence the best adaptation of organisms to constantly changing environmental conditions. This feature allowed eukaryotes to occupy a dominant position in

So, eukaryotes are organisms in whose cells there is a formed nucleus. These include plants, animals and fungi. The presence of a nucleus is a progressive feature of the structure, providing high level development and adaptation.

Bacteria are single-celled organisms that do not have a nucleus. That is, their DNA is not in a separate compartment, but is immersed directly in the contents of the cell. This is the key difference between bacteria and nuclear organisms, or eukaryotes, on the basis of which bacteria were isolated into a separate kingdom.

Bacteria have a relatively simple cellular organization, and it was they who became one of the first creatures to inhabit our planet. For millions of years, bacteria have been able to master almost all ecological niches. To adapt to unusual habitats, they had to develop unusual functions. They learned to eat light, oil, live in the Arctic cold and in boiling water, assemble their genome from pieces and synthesize hundreds of thousands of genomes.

Bacteria are 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 still formed, 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. The first nuclear cells evolved from bacteria about 1.4 billion years ago.

The most ancient of currently existing living organisms are considered archeobacteria thermoacidophiles. They live in hot spring water with a high acid content. Below 55oC (131oF) they die!

The most numerous

Bacteria are the main inhabitants of planet Earth. Their abundance is estimated at a figure with 30 zeros (approximately 4-6*1030), and the total biomass is about 550 billion tons. Every day, scientists discover several new types of bacteria. In addition, due to rapid reproduction and high mutation rate, bacteria constantly form new species. All new and new types. 90% of the biomass in the seas, it turns out, are microbes.

Life on Earth appeared

3.416 billion years ago, that is, 16 million years earlier than is commonly believed in scientific world. Analysis of one of the corals, which is more than 3.416 billion years old, proved that at the time of the formation of this coral, life already existed on Earth at the microbial level.

The oldest microfossil

Kakabekia barghoorniana (1964-1986) was found at Harich, Gunedd, Wales, estimated to be over 4,000,000,000 years old.

The oldest form of life

Fossilized imprints of microscopic cells have been found in Greenland. They turned out to be 3,800 million years old, making them the oldest known life forms.

Bacteria and eukaryotes

Life can exist in the form of bacteria - the simplest organisms that do not have a nucleus in the cell, the oldest (archaea), almost as simple as bacteria, but distinguished by an unusual membrane, eukaryotes are considered to be its peak - in fact, all other organisms whose genetic code is stored in cell nucleus.

Sense of smell even in bacteria

Almost all organisms, even bacteria, have the ability to recognize the presence of odorous substances in water or air.

extreme temperature lovers

Several decades ago, scientists discovered "black smokers" in the ocean - unique geothermal sources. "Black smokers" are formed, as a rule, in rift zones, where through cracks lithospheric plates incandescent gas erupts, heating the water to an extreme high temperatures- 300-400 degrees Celsius. Hydrogen sulfide and metal sulfides are dissolved in the water of "smokers", which color it black.

Scientists did not expect to find life in such conditions, however, to their surprise, the fauna of "black smokers" turned out to be very diverse. The rocky slopes around the "smokers" are inhabited by numerous bacteria. The water temperature around the slopes is slightly colder than in the heart of the "smoker" - only about 120 degrees Celsius. Bacteria adapted to boiling water thrive - they have no natural competitors.

Several types of bacteria have been found in the thickness of ice covering the subglacial Lake Vostok in Antarctica. They were, however, more dead than alive. Scientists have determined that the found bacteria are thermophilic - that is, they prefer to live at elevated temperatures. The researchers put forward a hypothesis according to which there are or were warm springs in Lake Vostok that heated the water of the lake.

By the way, it was the bacteria that were responsible for the formation of snowflakes. Recently, scientists have discovered that the “seed” for their formation in many cases are pathogenic microorganisms for plants. Pseudomonas syringae. Best of all, they "stimulate" the growth of crystalline ice structures at temperatures from minus seven degrees Celsius to zero.

Earth's oldest inhabitants found in Mariana Trench

At the bottom of the world's deepest Mariana Trench in the center Pacific Ocean 13 species of unicellular organisms unknown to science have been discovered that have existed unchanged for almost a billion years. Microorganisms were found in soil samples taken in the autumn of 2002 in the Challenger Fault by the Japanese automatic bathyscaphe Kaiko at a depth of 10,900 meters. In 10 cubic centimeters of soil, 449 previously unknown primitive unicellular round or elongated 0.5 - 0.7 mm in size were found. After several years of research, they were divided into 13 species. All these organisms almost completely correspond to the so-called. "unknown biological fossils" that were discovered in Russia, Sweden and Austria in the 80s in soil layers from 540 million to a billion years old.

Based on genetic analysis, Japanese researchers claim that single-celled organisms found at the bottom of the Mariana Trench have existed unchanged for more than 800 million, or even a billion years. Apparently, these are the most ancient of all the inhabitants of the Earth now known. Single-celled organisms from the Challenger Fault were forced to go to extreme depths in order to survive, because in the shallow layers of the ocean they could not compete with younger and more aggressive organisms.

The first bacteria appeared in the Archeozoic era

The development of the Earth is divided into five periods of time, which are called eras. The first two eras, Archaeozoic and Proterozoic, lasted 4 billion years, that is, almost 80% of the entire earth history. During the Archeozoic, the Earth was formed, water and oxygen arose. About 3.5 billion years ago, the first tiny bacteria and algae appeared. In the Proterozoic era, about 700 years ago, the first animals appeared in the sea. They were primitive invertebrates such as worms and jellyfish. The Paleozoic era began 590 million years ago and lasted 342 million years. Then the Earth was covered with swamps. During the Paleozoic, large plants, fish and amphibians appeared. The Mesozoic era began 248 million years ago and lasted 183 million years. At that time, the Earth was inhabited by huge lizard dinosaurs. The first mammals and birds also appeared. The Cenozoic era began 65 million years ago and continues to this day. At this time, the plants and animals that surround us today arose.

The biggest and smallest

In principle, large size is a disadvantage for bacteria, as they lack special nutrient uptake mechanisms. Most bacteria obtain food by simple diffusion. How larger size bacterial cell, the smaller the ratio of surface area to volume for it, which means that it is more difficult for it to get the required amount of food. That is, large bacteria are doomed to starvation. True, the giants have their own truth. Due to their size, they are difficult prey for predator bacteria, which feed on their prey by wrapping around and digesting them.

The smallest bacteria are comparable in size to large viruses. For example, Mycoplasma mycoides does not exceed 0.25 micrometers. According to theoretical calculations, a spherical cell with a diameter of less than 0.15-0.20 micrometers becomes incapable of independent reproduction, since all the necessary structures cannot physically fit in it.

Where do bacteria live

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 of the environment; 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.

Live in geothermal springs

archeobacteria Pyrodictium abyssi live near "black smokers" - geothermal sources heated to 300-400 degrees and saturated with hydrogen sulfide and metal sulfides

Living under the ice

Herminiimonas glaciei were discovered under the ice of Greenland at a depth of three kilometers. These are one of the smallest microorganisms known to scientists. With the help of a flagellum, they can move through thin channels in the thickness of the ice.

Living in a desert uninhabitable

Deinococcus peraridilitoris live in the soil in the Chilean Atacama Desert. Atacakma is so uninhabitable that NASA is using it as a testing ground for simulating conditions on Mars. The picture shows a close relative D. peraridilitoris - D. radiodurans

Live in salt marshes

Flat square archaeobacteria cells Haloquadratum walsbyi have the largest surface-to-volume ratio among all living beings. This geometry allows H. walsbyi survive in salt marshes near the Red Sea

Live in mines with high acidity

Archaea Ferroplasma acidophilum They thrive in the dumps of gold mines in California at a pH of 0. For comparison, the pH of concentrated hydrochloric acid in the human stomach is 1.5. The pH of pure water is 7.

Live in mines at a depth of three kilometers

Desulforudis audax viator are the most independent inhabitants of the planet Earth. These bacteria that live in uranium mines South Africa at a depth of three kilometers, they receive all the substances necessary for life absolutely independently. As energy to build your cells D. audax viator use radioactive radiation.

Bacteria are involved in digestion

The digestive tract of animals is densely populated with bacteria (usually harmless). For the life of most species, they are not required, 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.

The most resistant bacteria

X-ray or gamma radiation is deadly to living organisms. It causes breaks in DNA, and in large doses, literally tears it into pieces. However, some bacteria tolerate gamma radiation very well. This is about Deinococcus radiodurans. This bacterium multiplies after receiving a dose of radiation that is almost a thousand times higher than the lethal dose for humans. A unique organism completely restores its genome in just six hours. The secret is that Deinococcus radiodurans carries not one, like most bacteria, but several copies of its DNA. When irradiated, breaks in each of the copies occur in different places, so the bacterium can put together a whole mosaic of the available pieces.

Halobacterium salanarium NRC-1 able to survive exposure to 18 thousand grays. It takes 10 grays to kill a man

The most resourceful bacteria

By the way, Deinococcus radiodurans- far from champions in terms of the number of copies of their genome. Recently, microbiologists have been able to establish that bacteria from the genus Epulopiscium carry about 200,000 genomic copies in each cell. Moreover, their number correlates with the size of the bacterial cell. The evolutionary and ecological significance of this feature is still unclear. By the way, Epulopiscium Another feature that distinguishes them is their size. The cells of these microorganisms can reach 600 micrometers, while the average size of a bacterial cell ranges from 0.5 to 5 micrometers.

One dot holds a quarter of a million 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 bacteria will fit on the surface corresponding to the dot drawn with a pencil.

Bacteria give lessons on self-organization

In colonies of bacteria called stromatolites, the bacteria self-organize and form a huge working group, although none of them leads the rest. Such an association is very stable and quickly recovers in case of damage or a change in the environment. Also interesting is the fact that the bacteria in the stromatolite have different roles depending on where they are in the colony, and they all share common genetic information. All these properties can be useful for future communication networks.

The ability of bacteria

Many bacteria have chemical receptors that detect changes in the acidity of the environment and the concentration of sugars, amino acids, oxygen and carbon dioxide. Many motile bacteria also respond to temperature fluctuations, and photosynthetic species to changes in light. Some bacteria sense the direction of field lines magnetic field, including the Earth's magnetic field, with the help of magnetite particles (magnetic iron ore - Fe3O4) present in their cells. In water, bacteria use this ability to swim along lines of force in search of a favorable environment.

Memory of bacteria

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.

Bacteria double in number every 20 minutes

Partly due to the small size of bacteria, the intensity of their metabolism is very high. Under the most favorable conditions, some bacteria can double their total mass and numbers approximately every 20 min. This is due to the fact that a number of their most important enzyme systems function at a very high speed. So, a rabbit needs a few minutes to synthesize a protein molecule, and bacteria - seconds. However, in natural environment, for example, in the soil, most bacteria are "on a starvation diet", so if their cells divide, then not every 20 minutes, but every few days.

Within a day, 1 bacterium could form 13 trillion others

One bacterium of E. coli (Esherichia coli) during the day could produce offspring, the total volume of which would be enough to build a pyramid with an area of 2 sq. km and a height of 1 km. Under favorable conditions, in 48 hours, one cholera vibrio (Vibrio cholerae) would give offspring weighing 22 * 1024 tons, which is 4 thousand times more than the mass the globe. Fortunately, only a small number of bacteria survive.

How many bacteria are in the soil

AT top layer soil contains from 100,000 to 1 billion bacteria per 1 g, i.e. about 2 tons per hectare. Usually, all organic residues, once in the ground, are quickly oxidized by bacteria and fungi.

omnivores

Due to the rapid reproduction of bacteria, they are constantly in conditions of fierce competition. To survive, they have learned to find food sources in almost everything. The most obvious and accessible became sunlight. With its help, for example, cyanobacteria, which are also called blue-green algae, receive energy. They obtain the energy they need to live through the process of oxygenic photosynthesis, which requires only light, water and carbon dioxide. Oxygen is released as a by-product of photosynthesis. It was cyanobacteria that saturated the Earth's atmosphere with oxygen, without which most organisms cannot exist.

In an effort to ensure a peaceful existence, some bacteria preferred to find other food sources. To do this, they needed to seriously change their cellular organization, but such a restructuring made it possible to occupy a free ecological niche. Several groups of bacteria have evolved the ability to recycle oil. Bacteria belonging to the genera Pseudomonas, Bacillus, Serratia, Alcaligenes complicate the life of oil workers, decomposing various components of oil into simple hydrocarbons. However, bacteria with such non-standard food habits can also be beneficial. At present, scientists from different countries are actively developing technologies for cleaning water after oil spills using oil-oxidizing bacteria.

Some bacteria living in the soil have learned to feed on substances specially designed to destroy them. Scientists have discovered several hundred species of bacteria that can use antibiotics as their sole source of nutrition. Such bacteria are potentially dangerous to humans, even if they themselves do not cause any disease. Antibiotic enthusiasts can pass on their genes to pathogens, a practice that is very common among bacteria.

Bacteria eat pesticides

A genetically modified common E. coli is capable of eating organophosphorus compounds - poisonous substances that are toxic not only to insects, but also to humans. The class of organophosphorus compounds includes some types of chemical weapons, such as sarin gas, which has a nerve-paralytic effect.

A special enzyme, a kind of hydrolase, originally found in some "wild" soil bacteria, helps modified E. coli to deal with organophosphorus. After testing many genetically related varieties of the bacteria, the scientists selected a strain that was 25 times more effective at killing the pesticide methyl parathion than the original soil bacteria. So that the toxin eaters would not "run away", they were fixed on a matrix of cellulose - it is not known how the transgenic E. coli will behave once it is released.

Bacteria will happily eat plastic with sugar

Polyethylene, polystyrene and polypropylene, which make up one fifth of urban waste, have become attractive to soil bacteria. When mixing the styrene units of polystyrene with a small amount of another substance, "hooks" are formed, for which particles of sucrose or glucose can catch on. Sugars "hang" on styrene chains like pendants, making up only 3% of the total weight of the resulting polymer. But Pseudomonas and Bacillus bacteria notice the presence of sugars and, by eating them, destroy the polymer chains. As a result, within a few days, the plastics begin to decompose. The final products of processing are carbon dioxide and water, but organic acids and aldehydes appear on the way to them.

Succinic acid from bacteria

In the rumen - a section of the digestive tract of ruminants - a new type of bacteria producing succinic acid was discovered. Microbes live and multiply perfectly without oxygen, in an atmosphere of carbon dioxide. In addition to succinic acid, they produce acetic and formic. The main nutritional resource for them is glucose; from 20 grams of glucose, bacteria create almost 14 grams of succinic acid.

Deep Sea Bacteria Cream

Bacteria harvested from a hydrothermal fissure 2km deep in California's Pacific Bay will help create a lotion to effectively protect your skin from the sun's damaging rays. Among the microbes that live here at high temperatures and pressures, there is Thermus thermophilus. Their colonies thrive at 75 degrees Celsius. Scientists are going to use the fermentation process of these bacteria. The result will be a "protein cocktail" including enzymes that are especially zealous in destroying highly active chemical compounds, formed when exposed to ultraviolet rays and involved in reactions that destroy the skin. According to the developers, the new components can destroy hydrogen peroxide three times faster at 40 degrees Celsius than at 25.

Humans are hybrids of Homo sapiens and bacteria

Man is a collection of, in fact, human cells, as well as bacterial, fungal and viral life forms, say the British, and human genome in this conglomerate does not predominate at all. In the human body, there are several trillion cells and more than 100 trillion bacteria, five hundred species, by the way. Bacteria, not human cells, lead in terms of the amount of DNA in our bodies. This biological cohabitation is beneficial to both parties.

Bacteria accumulate uranium

One strain of the bacterium Pseudomonas is able to efficiently capture uranium and other heavy metals from the environment. Researchers have isolated this type of bacteria from the wastewater of one of the Tehran metallurgical plants. The success of cleaning work depends on the temperature, acidity of the environment and the content of heavy metals. The best results were at 30 degrees Celsius in a slightly acidic environment with a uranium concentration of 0.2 grams per liter. Its granules accumulate in the walls of bacteria, reaching 174 mg per gram of bacteria dry weight. In addition, the bacterium captures copper, lead and cadmium and other heavy metals from the environment. The discovery can serve as a basis for the development of new methods of wastewater treatment from heavy metals.

Two species of bacteria unknown to science found in Antarctica

The new microorganisms Sejongia jeonnii and Sejongia antarctica are gram-negative bacteria containing a yellow pigment.

So many bacteria on the skin!

On the skin of rodent mole rats, there are up to 516,000 bacteria per square inch; on dry areas of the skin of the same animal, for example, on the front paws, there are only 13,000 bacteria per square inch.

Bacteria against ionizing radiation

The microorganism Deinococcus radiodurans is capable of withstanding 1.5 million rads. ionizing radiation exceeding the lethal level for other life forms by more than 1000 times. While the DNA of other organisms will be destroyed and destroyed, the genome of this microorganism will not be damaged. The secret of such stability lies in the specific shape of the genome, which resembles a circle. It is this fact that contributes to such resistance to radiation.

Microorganisms against termites

Formosan (USA) termite control agent uses natural enemies of termites - several types of bacteria and fungi that infect and kill them. After an insect is infected, fungi and bacteria settle in its body, forming colonies. When an insect dies, its remains become a source of spores that infect fellow insects. Microorganisms were selected that reproduce relatively slowly - the infected insect should have time to return to the nest, where the infection will be transmitted to all members of the colony.

Microorganisms live at the pole

Microbial colonies have been found on rocks near the north and south poles. These places are not very suitable for life - the combination of extremely low temperatures, strong winds and harsh ultraviolet radiation looks awesome. But 95 percent of the rocky plains studied by scientists are inhabited by microorganisms!

These microorganisms have enough of the light that enters under the stones through the gaps between them, reflecting from the surfaces of neighboring stones. Due to temperature changes (stones are heated by the sun and cool down when it is not), shifts occur in stone placers, some stones are in complete darkness, while others, on the contrary, fall into the light. After such shifts, microorganisms "migrate" from darkened stones to illuminated ones.

Bacteria live in slag heaps

The most alkali-loving living organisms on the planet live in polluted water in the United States. Scientists have discovered microbial communities thriving in slag heaps in the Calume Lake area of southwest Chicago, where the water's pH is 12.8. Living in such an environment is comparable to living in caustic soda or floor washing liquid. In such dumps, air and water react with slags, in which calcium hydroxide (caustic soda) is formed, which increases the pH. The bacterium was discovered in a study of contaminated groundwater from more than a century of industrial iron dumps from Indiana and Illinois.

Genetic analysis has shown that some of these bacteria are close relatives of Clostridium and Bacillus species. These species have previously been found in the acidic waters of Mono Lake in California, tuff pillars in Greenland, and cement-contaminated waters of a deep gold mine in Africa. Some of these organisms use hydrogen released during the corrosion of metallic iron slags. How exactly the unusual bacteria got into the slag heaps remains a mystery. It is possible that the native bacteria have adapted to their extreme habitat over the past century.

Microbes determine water pollution

Modified E. coli bacteria are grown in an environment with pollutants and their amount is determined at different points in time. Bacteria have a built-in gene that allows cells to glow in the dark. By the brightness of the glow, you can judge their number. Bacteria are frozen in polyvinyl alcohol, then they can withstand low temperatures without serious damage. They are then thawed, grown in suspension, and used in research. In a polluted environment, cells grow worse and die more often. The number of dead cells depends on the time and degree of contamination. These indicators differ for heavy metals and organic substances. For any substance, the rate of death and the dependence of the number of dead bacteria on the dose are different.

Viruses have

A complex structure of organic molecules, which is even more important - the presence of its own, viral genetic code and the ability to reproduce.

Origin of viruses

It is generally accepted that viruses originated as a result of the isolation (autonomization) of individual genetic elements of the cell, which, in addition, received the ability to be transmitted from organism to organism. The size of viruses varies from 20 to 300 nm (1 nm = 10–9 m). Almost all viruses are smaller in size than bacteria. However, the largest viruses, such as the vaccinia virus, are the same size as the smallest bacteria (chlamydia and rickettsia.

Viruses - a form of transition from mere chemistry to life on Earth

There is a version that viruses arose once a very long time ago - thanks to the intracellular complexes that gained freedom. Inside a normal cell, there is a movement of many different genetic structures (messenger RNA, etc., etc.), which can be the progenitors of viruses. But, perhaps, everything was quite the opposite - and viruses are the oldest form of life, or rather the transitional stage from "just chemistry" to life on Earth.
Even the origin of the eukaryotes themselves (and, therefore, of all unicellular and multicellular organisms, including you and me), some scientists associate with viruses. It is possible that we appeared as a result of the "collaboration" of viruses and bacteria. The first provided genetic material, and the second - ribosomes - protein intracellular factories.

Viruses cannot

... reproduce on their own - for them, it is done by the internal mechanisms of the cell that the virus infects. The virus itself cannot work with its genes either - it is not able to synthesize proteins, although it has a protein shell. It simply steals ready-made proteins from cells. Some viruses even contain carbohydrates and fats - but again stolen ones. Outside the victim cell, the virus is just a giant accumulation of very complex molecules, but you don’t have a metabolism, or any other active actions.

Surprisingly, the simplest creatures on the planet (we will still conventionally call viruses creatures) are one of the biggest mysteries of science.

The largest Mimi virus, or Mimivirus

... (which causes an outbreak of influenza) is 3 times more than other viruses, 40 times more than others. It carries 1260 genes (1.2 million "letter" bases, which is more than other bacteria), while known viruses have only three to a hundred genes. At the same time, the genetic code of a virus consists of DNA and RNA, while all known viruses use only one of these "tablets of life", but never both together. 50 Mimi genes are responsible for things that have never been seen in viruses before. In particular, Mimi is capable of independently synthesizing 150 types of proteins and even repairing its own damaged DNA, which is generally nonsense for viruses.

Changes in the genetic code of viruses can make them deadly

American scientists experimented with the modern flu virus - a nasty and severe, but not too lethal disease - by crossing it with the virus of the infamous "Spanish flu" of 1918. The modified virus killed mice on the spot with symptoms characteristic of the "Spanish flu" (acute pneumonia and internal bleeding). At the same time, its differences from the modern virus at the genetic level turned out to be minimal.

From the epidemic of "Spanish flu" in 1918 died more people than during the most terrible medieval epidemics of plague and cholera, and even more than front-line losses in the First world war. Scientists suggest that the Spanish flu virus could have arisen from the so-called "bird flu" virus, combining with a common virus, for example, in the body of pigs. If avian flu successfully interbreeds with human flu and gets the opportunity to pass from person to person, then we get a disease that can cause a global pandemic and kill several million people.

The strongest poison

It is now considered to be the toxin of bacillus D. 20 mg of it is enough to poison the entire population of the Earth.

Viruses are sets of genetic information

Viruses can swim

Eight types of phage viruses live in Ladoga waters, differing in shape, size and length of legs. Their number is much higher than typical for fresh water: two to twelve billion particles per liter of sample. In some samples there were only three types of phages, their highest content and diversity was in the central part of the reservoir, all eight types. Usually the opposite happens, there are more microorganisms in the coastal areas of lakes.

Silence of viruses

Many viruses, such as herpes, have two phases in their development. The first occurs immediately after infection of the new host and does not last long. Then the virus, as it were, "falls silent" and quietly accumulates in the body. The second can begin in a few days, weeks or years, when the "silent" virus for the time being begins to multiply like an avalanche and causes a disease. The presence of a "latent" phase protects the virus from extinction when the host population quickly becomes immune to it. The more unpredictable the external environment is from the point of view of the virus, the more important it is for it to have a period of "silence".

Viruses play an important role

In the life of any reservoir, viruses play important role. Their number reaches several billion particles per liter of sea water in polar, temperate and tropical latitudes. In freshwater lakes, the virus content is usually less than 100 times. Why there are so many viruses in Ladoga and they are so unusually distributed remains to be seen. But researchers have no doubt that microorganisms have a significant impact on the ecological state of natural water.

Where do amoebas live

A positive reaction to a source of mechanical vibrations was found in an ordinary amoeba

Amoeba proteus is a freshwater amoeba about 0.25 mm long, one of the most common species of the group. It is often used in school experiments and for laboratory research. The common amoeba is found in the mud at the bottom of ponds with polluted water. It looks like a small, colorless gelatinous lump, barely visible to the naked eye.

In the common amoeba (Amoeba proteus), the so-called vibrotaxis was found in the form of a positive reaction to a source of mechanical vibrations with a frequency of 50 Hz. This becomes clear if we consider that in some species of ciliates that serve as food for the amoeba, the frequency of the beating of cilia fluctuates between 40 and 60 Hz. The amoeba also exhibits negative phototaxis. This phenomenon consists in the fact that the animal tries to move from the illuminated area to the shade. Thermotaxis in the amoeba is also negative: it moves from a warmer to a less heated part of the water body. It is interesting to observe the galvanotaxis of the amoeba. If a weak one is passed through the water electricity, the amoeba releases pseudopods only from the side that faces the negative pole - the cathode.

The largest amoeba

One of the largest amoebas is the freshwater species Pelomyxa (Chaos) carolinensis, 2–5 mm long.

Amoeba moves

The cytoplasm of the cell is in constant motion. If the current of the cytoplasm rushes to one point on the surface of the amoeba, a protrusion appears on its body in this place. It increases, becomes an outgrowth of the body - a pseudopod, cytolasm flows into it, and the amoeba moves in this way.

Midwife for amoeba

The amoeba is a very simple organism, consisting of a single cell that reproduces by simple division. First, the amoeba cell doubles its genetic material, creating a second nucleus, and then changes shape, forming a constriction in the middle, which gradually divides it into two daughter cells. Between them there is a thin bundle, which they pull in different directions. In the end, the ligament breaks, and the daughter cells begin an independent life.

But in some species of amoeba, the process of reproduction is not at all so simple. Their daughter cells cannot break the ligament on their own and sometimes merge again into one cell with two nuclei. The dividing amoebas cry out for help by releasing a special chemical to which the "midwife amoeba" responds. Scientists believe that, most likely, this is a complex of substances, including fragments of proteins, lipids and sugars. Apparently, when an amoeba cell divides, its membrane experiences tension, which causes the release of a chemical signal into the external environment. Then the dividing amoeba is helped by another, which comes in response to a special chemical signal. It is introduced between dividing cells and puts pressure on the ligament until it breaks.

living fossils

The most ancient of them are radiolarians, single-celled organisms covered with a shell-like growth with an admixture of silica, the remains of which were found in Precambrian deposits, whose age is from one to two billion years.

The most enduring

The tardigrade, an animal less than half a millimeter long, is considered the hardiest life form on Earth. This animal can withstand temperatures from 270 degrees Celsius to 151 degrees, exposure to X-rays, vacuum conditions and pressures six times the pressure at the bottom of the deepest ocean. Tardigrades can live in gutters and in cracks in masonry. Some of these little creatures came to life after a century of hibernation in the dry moss of museum collections.

Acantharia (Acantharia), the simplest organisms related to radiolarians reach a length of 0.3 mm. Their skeleton is made up of strontium sulfate.

The total mass of phytoplankton is only 1.5 billion tons, while mass of zoopalnkton– 20 billion tons.

Travel speed shoe ciliates (Paramecium caudatum) is 2 mm per second. This means that the shoe swims in a second a distance 10-15 times greater than the length of its body. There are 12 thousand cilia on the surface of the ciliates-shoes.

Euglena green (Euglena viridis) can serve as a good indicator of the degree biological treatment water. With a decrease in bacterial pollution, its number increases sharply.

What were the earliest forms of life on earth?

Creatures that are neither plants nor animals are called rangeomorphs. They first settled on the ocean floor about 575 million years ago, after the last global glaciation (this time is called the Ediacaran period), and were among the first soft-bodied creatures. This group existed until 542 million years ago, when rapidly reproducing modern animals displaced most of these species.

Organisms were collected in fractal patterns of branching parts. They were unable to move and did not have reproductive organs, but multiplied, apparently creating new offshoots. Each branching element consisted of many tubes held together by a semi-rigid organic skeleton. Scientists have discovered rangeomorphs collected in several different forms, which, he believes, collected food in different layers of the water column. The fractal pattern appears to be quite complex, but according to the researcher, the similarity of organisms to each other made a simple genome sufficient to create new free-floating branches and to connect branches into more complex structures.

The fractal organism found in Newfoundland was 1.5 centimeters wide and 2.5 centimeters long.
Such organisms accounted for up to 80% of all living in the Ediacaran when there were no mobile animals. However, with the advent of more mobile organisms, their decline began, and as a result they were completely supplanted.

Deep under the ocean floor there is immortal life

Under the surface of the bottom of the seas and oceans there is a whole biosphere. It turns out that at depths of 400-800 meters below the bottom, in the thickness of ancient sediments and rocks, myriads of bacteria live. The age of some specific specimens is estimated at 16 million years. They are practically immortal, scientists say.

Researchers believe that it was in such conditions, in the depths of bottom rocks, that life originated more than 3.8 billion years ago and only later, when the environment on the surface became habitable, did it master the ocean and land. Traces of life (fossils) in bottom rocks taken from a very great depth under the bottom surface have been found by scientists for a long time. Collected mass of samples in which they found living microorganisms. Including - in rocks raised from depths of more than 800 meters below the ocean floor. Some sediment samples were many millions of years old, which meant that, for example, a bacterium trapped in such a sample had the same age. About a third of the bacteria that scientists have found in deep bottom rocks are alive. In the absence of sunlight, the source of energy for these creatures is various geochemical processes.

The bacterial biosphere located under the seabed is very large and outnumbers all bacteria living on land. Therefore, it has a noticeable effect on geological processes, on the balance of carbon dioxide, and so on. Perhaps, the researchers suggest, without such underground bacteria, we would not have oil and gas.

a) algae
b) mosses
c) bacteria
d) ferns

Of course it's bacteria.

Read also

2) vacuoles 3) chromosomes 4) ribosomes A5 Cells of organisms that do not have a formalized nucleus are 1) fungi 2) algae 3) bacteria 4) protozoa A6 The end products of the oxidation of carbohydrates and fats are 1) water and carbon dioxide 2) amino acids and urea 3) glycerol and fatty acids 4) glucose and glycogen A7 The nucleus contains a special substance from which 1. ribosomes are formed before division 2. mitochondria 3. chromosomes 4. lysosomes A8 The genotype of the daughter organism differs significantly from the genotype of the parent organisms during 1. sexual reproduction 2. asexual dissolution 3. vegetative dissolution 4. A9 budding .AABB 3.AABB 4.AABB

b) in living organisms consisting of one cell, gas exchange with environment occurs across the surface of the cell.

c) the substance created by living organisms is called organic.

d) in all marine animals, the respiratory organs are gills.

e) ecology studies the relationship of organisms with each other and the environment.

e) meadow food chain: snake-toad-chamomile-heron-grasshopper

Cells can be divided into two types: without a formed nucleus (prokaryotic cells, for example, bacteria) and with a nucleus covered with a membrane (eukaryotic cells, i.e., animal and plant cells). Despite these and other differences, all cells have common features: they are surrounded by a membrane, their genetic information is stored in genes, proteins are their main structural material and biocatalysts, and they are synthesized on ribosomes. Cells use adenosine triphosphate (ATP) as an energy source. Viruses do not have all of the listed characteristics of cells and do not belong to living organisms, although they are sometimes called non-cellular life forms. There are unicellular organisms consisting of one cell (bacteria, protozoa and unicellular algae). Multicellular animals (Metazoa) and plants (Metaphyta) contain many differentiated (specialized) cells that perform various functions. DNA in all cells of one eukaryotic organism (except for sex cells), including stem cells, is the same. Cells of different organs and tissues, such as bone cells and nerve cells, differ due to the regulation of gene expression. Stem cells are special cells of organisms that are able to differentiate and turn into specialized cells of organs and tissues. Currently, on the basis of stem cells, a new direction of treatment is being developed - cell therapy - transplantation of living cells into the human body to replace lost, inactive or damaged cells and restore the structure and functions of tissues and organs.

Naroditsky Boris Savelievich

Shirinsky Vladimir Pavlovich

Nesterenko Ludmila Nikolaevna

Alberts B., Johnson A., Lewis J. et al. Molecular Biology of the Cell. 4th ed. - N.Y.: Garland Publishing, 2002. - 265 p.
Glick B., Pasternak J. Molecular Biotechnology: Principles and Applications. - M.: Mir, 2002. - 589 p.
Cell // Wikipedia, the free encyclopedia. - http://ru.wikipedia.org/wiki/Cell (date of access: 10/12/2009).

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Preparation for the OGE on the topic "Cage"

This Verification work will allow you to check how the trainees have mastered this material. You can spend before studying the topic to find out the gaps in this topic and after studying the topic.

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"preparation for the OGE"

Part A assignments
A1. The main property of the plasma membrane is

1) contractility 2) impermeability 3) absolute excitability

4) selective permeability

A2. Which organism does NOT have a cellular structure?

1) common amoeba 2) bird flu virus 3) yeast 4) erythrocyte

A3. The creators of the cell theory are

1) R. Hooke and A. Levenguk

2) N.I. Vavilov and I.V. Michurin

3) M. Schleiden and T. Schwann

4) T.H. Morgan and G. Freese

A4. What is the function of leukoplasts?

1) accumulation of starch 2) ensuring the color of fruits, flowers

3) participation in water metabolism 4) photosynthesis

A5. Molecules are synthesized in ribosomes

1) proteins 2) carbohydrates 3) nucleic acids 4) lipids

A6. What cells are involved in the process of blood clotting in humans?

1) leukocytes 2) lymphocytes 3) platelets 4) erythrocytes

A7. Choose a trait characteristic of prokaryotic cells.

1) there are no ribosomes in the cell

2) there is no developed system of membranes in the cell

3) have linear DNA molecules associated with proteins

4) the genetic material is enclosed in the nucleus

A8. What substance is in the cell wall of fungi?

1) starch 2) murein 3) chitin 4) cellulose
A9. What cell organelle is shown in the picture?

1) cell center 2) mitochondria 3) ribosome 4) Golgi apparatus

1) water 2) ground-air 3) soil 4) organism

A11. The non-cellular form of life is

1) bacterium 2) amoeba cyst 3) blue green algae 4) virus

A12. The main position of the "cell theory" is the statement

1) all cells contain the same set of organelles

2) the cellular structure of all living organisms is evidence of the spontaneous generation of cells from a structureless intercellular substance

3) all living organisms are made up of cells, the cell is the structural and functional unit of the living

4) cells of animals, plants and fungi are the same in structure and chemical composition

A13. Chloroplasts are found in cells

1) green mold 2) chlamydomonas 3) pine stem wood 4) onion root

A14. The nucleus is in

1) human immunodeficiency virus 2) nitrogen-fixing bacteria

3) malarial plasmodium 4) Escherichia coli

A15. Who was the first to discover cells in a cork section and who first used the term "cell"?

1) Robert Hooke 2) Anthony van Leeuwenhoek

3) Matthias Schleiden and Thomas Schwann 4) Rudolf Virchow

A16. What cell structures do all living organisms have except viruses?

1) cell membrane 2) vacuole 3) chloroplast 4) nucleus

A17. What is the genetic material of viruses?

1) nucleic acid 2) capsid 3) nucleoid 4) chromosome

A18. He was the first to use a microscope to study biological objects and introduced the term cell into science.

1) Matthias Schleiden 2) Robert Hooke 3) Theodor Schwann 4) Anthony van Leeuwenhoek

A19. Organisms whose cells have a distinct nucleus are called

1) viruses 2) bacteria 3) prokaryotes 4) eukaryotes

A20. The position of the cell theory, belonging to R. Virchow, is the statement

1) a multicellular organism develops from a single source cell

2) the cells of all organisms have a similar chemical composition and general building plan

3) a new cell arises as a result of the division of the mother cell

4) all organisms consist of the same structural units - cells

A21. Prokaryotes are

1) animals and mushrooms 2) higher plants and green algae

3) bacteria and blue-green algae 4) viruses and protozoa

A22. Indicate the position of the cell theory

1) a unicellular organism develops from several initial cells

2) plant and animal cells are the same in structure and chemical composition

3) every cell in the body is capable of meiosis

4) the cells of all organisms are similar in structure and chemical composition

A23. What level of organization of the living is the main object of study of cytology?

1) cellular 2) organ-tissue 3) organism 4) population-species

A24. characteristic feature bacteria is

1) no nucleus 2) no cytoplasm

3) the presence of cytoplasm 4) the presence of the nucleus

A25. Linear DNA molecules associated with proteins, organized into chromosomes, are present in

1) viruses 2) bacteria 3) blue-green algae 4) fungi

A26. What cells do NOT have a cell wall?

1) bacteria 2) fungi 3) plants 4) animals

A27. The subject of study of which science is the object depicted in the figure?

1) paleontology 2) systematics 3) cytology 4) ecology

A28. The eukaryotes are

1) viruses 2) bacteria 3) yeast 4) bacteriophages

A29. The function of chloroplasts in plant cell is an

2) the formation of organic substances from inorganic substances using light energy

3) transport of substances

4) the formation of inorganic substances from organic substances in the process of respiration

A30. The main function of mitochondria is

1) protein synthesis 2) formation of lysosomes 3) ATP synthesis 4) photosynthesis

A31. Organisms consisting of one cell and not having a formed nucleus are classified as kingdom

1) plants 2) animals 3) viruses 4) bacteria

A32. What tissue contains the cell shown in the picture?

1) connective 2) nervous 3) epithelial 4) muscular

Part B assignments

IN 1. Establish a correspondence between human germ cells and their structure: for each element of the first column, select a position from the second column.

FEATURES OF THE STRUCTURE SEX CELLS

A) have a tail 1) spermatozoa

B) a large volume of cytoplasm 2) eggs

B) supply of nutrients

D) bigger

E) have an acrosome

Write the selected numbers under the corresponding letters in the table.

Control work on the topic "Kingdoms of bacteria and fungi"

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Examination No. 2

PART A (Choose one correct answer)

Organisms consisting of one cell and not having a formed nucleus are:

Spherical bacteria are:

The formation of spores by bacteria is an adaptation to:

b) transferring adverse conditions

The fluffy white coating of mucor turns black after a while, because:

a) its threads die and rot

b) with age, black substances are formed in the threads

c) spores form in its heads

Fungi are not capable of photosynthesis because:

a) they live in the soil

b) do not have chloroplasts

d) are small

The fruiting body is:

c) stem and cap of the mushroom

d) mushroom leg and mycelium

According to the nature of nutrition, mushrooms are:

c) autotrophs and heterotrophs at the same time

Molds include:

An ear of cereal struck by a smut is filled with:

b) fruiting body

d) mycelium, fruiting bodies, spores

Mushrooms eat ready organic matter

All bacteria have chlorophyll and are capable of photosynthesis.

Kefir is formed as a result of the activity of bacteria

Bacteria do not have a well-formed nucleus

All mushrooms are built from intertwined threads - hyphae, forming a mycelium - mycelium

Bacteria reproduce by dividing one cell into two

Cap mushroom spores are formed in plates or tubules.

Bacteria are unicellular plants

The fruiting body of a fungus is made up of a cap, stalk, and mycelium.

PART C (Define)

During the war years, the preparation of the fungus penicilla saved many wounded and patients with pneumonia from death. What property does it have?

The Kingdom of Bacteria. Mushroom Kingdom"

Organisms that do not have a formed nucleus in their cells include:

Bacteria easily tolerate frost and heat, because:

a) multiply rapidly

b) do not breathe, do not grow

c) may not eat

d) can form disputes

a) organic matter of living organisms

b) minerals

c) organic matter of dead organisms

d) water and carbon dioxide

Mukor is most often found:

c) on wet bread

Mushrooms are classified as a separate kingdom because they:

a) immobile but capable of photosynthesis

b) immobile and feed on ready-made organic substances

c) do not reproduce by spores and do not have organs

d) do not have organs, but they themselves create organic substances

The edible part of the mushroom is called:

d) fruiting body

In the brushes of the mycelium, the spores are located at:

The set of hyphae form:

c) fruiting body

a) form organic substances in the light

b) ready-made organic substances

c) only organic substances of living organisms

d) living on food

PART B (answer yes or no)

Bacteria are unicellular organisms

Bacteria do not have a distinct nucleus

most bacteria feed on ready-made organic substances

Bacteria can form spores

Bacteria reproduce by dividing one cell into two

Penicillium is a type of fungus

Yeast unicellular fungi

Yeast, like other fungi, reproduces by spores.

Molds reproduce by spores

PART D (answer the question)

Baker's yeast is added to the bread dough. What would bread be like without yeast? Why?

Pantina Evgenia Evgenievna
29.03.2016

Material number: DV-567149

Publication Certificate this material the author can download in the "Achievements" section of his site.

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If we imagine a restaurant serving various bacteria, then the menu of such an institution would consist of many volumes, and visitors would not be able to “try” all the dishes even in a few years. A list of section names alone in such a menu would take more than one page: bacteria of the most unusual appearance, bacteria of all colors of the rainbow, bacteria with the most unusual diet, the most ancient bacteria. It seems that there is not a single place on our planet where bacteria have not been found.

omnivores

Due to the rapid reproduction of bacteria, they are constantly in conditions of fierce competition. To survive, they have learned to find food sources in almost everything. The most obvious and accessible was sunlight. With its help, for example, cyanobacteria, which are also called blue-green algae, receive energy. They obtain the energy they need to live through the process of oxygenic photosynthesis, which requires only light, water and carbon dioxide. Oxygen is released as a by-product of photosynthesis. It was cyanobacteria that saturated the Earth's atmosphere with oxygen, without which most organisms cannot exist.

In an effort to ensure a peaceful existence, some bacteria preferred to find other food sources. To do this, they needed to seriously change their cellular organization, but such a restructuring made it possible to occupy a free ecological niche. Several groups of bacteria have evolved the ability to recycle oil. Bacteria belonging to the genera Pseudomonas, Bacillus, Serratia, Alcaligenes complicate the life of oil workers, decomposing various components of oil into simple hydrocarbons. However, bacteria with such non-standard food habits can also be beneficial. Currently, scientists from different countries are actively developing technologies for cleaning water after oil spills using oil-oxidizing bacteria.

extreme temperature lovers

"Black smokers" Photo from uni-bremen.de

Several decades ago, scientists discovered "black smokers" in the ocean - unique geothermal sources. "Black smokers" are formed, as a rule, in rift zones, where hot gas breaks through cracks in lithospheric plates, heating water to extremely high temperatures - 300-400 degrees Celsius. Hydrogen sulfide and metal sulfides are dissolved in the water of "smokers", which color it black.

By the way, it was the bacteria that were responsible for the formation of snowflakes. Recently, scientists have discovered that the "seed" for their formation, in many cases, pathogenic microorganisms for plants Pseudomonas syringae. Best of all, they "stimulate" the growth of crystalline ice structures at temperatures from minus seven degrees Celsius to zero.

The most resistant bacteria

The most resourceful bacteria

By the way, Deinococcus radiodurans- far from champions in terms of the number of copies of their genome. Recently, microbiologists have been able to establish that bacteria from the genus Epulopiscium each cell has about 200,000 genomic copies. Moreover, their number correlates with the size of the bacterial cell. The evolutionary and ecological significance of this feature is still unclear. By the way, Epulopiscium Another feature that distinguishes them is their size. The cells of these microorganisms can reach 600 micrometers, while the average size of a bacterial cell ranges from 0.5 to 5 micrometers.

The biggest and smallest

In principle, large size is a disadvantage for bacteria, as they lack special nutrient uptake mechanisms. Most bacteria obtain food by simple diffusion. The larger the size of a bacterial cell, the smaller its surface area to volume ratio, which means that it is more difficult for it to get the required amount of food. That is, large bacteria are doomed to starvation. True, the giants have their own truth. Due to their size, they are difficult prey for predator bacteria, which feed on their prey by wrapping around and digesting them.

The smallest bacteria are comparable in size to large viruses. For example, mycoplasma Mycoplasma mycoides does not exceed 0.25 micrometers. According to theoretical calculations, a spherical cell with a diameter of less than 0.15-0.20 micrometers becomes incapable of independent reproduction, since all the necessary structures cannot physically fit in it.

The most numerous

Finally, bacteria are the main inhabitants of the planet Earth. Their number is estimated by a figure with 30 zeros (approximately 4-6 * 10 30), and the total biomass is about 550 billion tons. Every day, scientists discover several new types of bacteria. In addition, due to rapid reproduction and high mutation rate, bacteria constantly form new species. All new and new types.

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