Viruses. Differences between viral and bacterial infections What is a virus

A virus is an infectious agent that can reproduce only in living cells of a person, animal, plant or bacteria.

The soil for the development of viruses in the human body is energy of a certain quality, of a destructive nature, produced by it as a result of internal problems with self-esteem, self-esteem, and the meaning of one’s existence.

The appearance of viruses in the body signals a person about the lack of joy in life, the collapse of any illusion and the experience of sadness and bitterness about this. A similar quality of vibrations (energy), which creates the ground for infection with a virus, for example, through sexual contact, can be created both in the current life and be inherited, in the form of hereditary programs (predisposition, vibration, information) that carry a message ancestors about the low meaning of life that guided them, the humiliation they experienced, the loss of the Divine in themselves, unworthiness, disappointment and longing for what was lost.

The transferred program can “sleep” and become more active in a situation where a person experiences deep disappointment, decreased self-esteem, infringement of dignity, and loss of the previously existing meaning of life. The state of a person in such experiences is a certain quality of energy, supported by the current situation and hereditary programs, which create the best conditions for infection with the virus.

First, an infection with a virus occurs as a result of favorable conditions for its life, and then the virus, as the simplest creature that wants to live, begins to maintain these conditions for its existence - an energetic-informational background of loss, despondency, and humiliation of a person. It turns out to be a vicious circle, supported from two sides: by a person, who thinks and feels in a certain way, and by a virus, which multiplies and maintains infected energy in the body.

The virus integrates into the cell and becomes part of the person.

To kill the virus, you need to kill part of the person. Medicine treats the virus with drugs, and the virus feeds on energy, on humans.

A person swallows a pill, but he doesn’t stop thinking and feeling humiliated, lost, meaningless. The antiviral drug affects anything, just not thoughts.

To kill a virus, it is necessary to cure a person of the causes that create vibrations favorable to the life of the virus.

If a person does not change his attitude towards himself and the world, does not discover meanings that heal his self-esteem, melancholy, sadness, loss, the virus will live and prosper.

At a young age, for example, the herpes virus manifests itself as a cold on the lips. A person drives away his thoughts and attitude towards himself and the world with the help of hyper-activity (career, family, children, travel, etc.) In old age, a person has little activity, but has a lot of thoughts about himself and the life he has lived. Everything that has been driven away rolls up and covers your head, and the overall energy of the body decreases.

What can I say, old people are not in demand in society, and often they are not needed by their family and friends, so they have no joy in life at all. Add to this separation from the Divine, if a very old person is not a believer and does not experience unity with God. This is where the lurking herpes virus (shingles, Zoster) can roam. This is a very severe form, with serious pain.

Medicine does not treat this; it begins to poison the old body with drugs to suppress the virus and relieve pain. All drugs for old people affect brain activity (and let’s not think about all this bullshit, but medicine has an official scientific explanation, however, the essence is the same), they become lethargic, absent-minded, sleep more, think less, live under the drugs like plants.

Old people often simply do not have the strength to change anything in their heads and souls. Plus, intransigence and the habit of defending one’s worldview (beliefs) are reliably developed in a person from childhood. All this does not allow the quality of energy (vibration) of the old person to change. Neither in the soul nor in the head does a person have God, there is no correct idea of the world, the meaning of life. And life is on the wane...

My old mother's herpes began to develop as colds on her lips when my father had a stroke. Mom began to be afraid of being left alone, the foundations of life began to shake... Herpes raged in full force 2 months after the death of my father.

The meaning of her life limped on both legs and herpes struck with such force, with such pain that she was forced to forget about the departure of a loved one with whom she had lived for almost 60 years. There was no time to grieve and there was no strength left to grieve, only pain. I had to get active, get treatment, look for a way to recovery so that the virus would recede.

This is another unobvious task of the virus - to force the cell to become active. He lives at the expense of its resources, so the cell, in order to survive, will need to be active or die... Through the cell, the virus pushes the entire body to enter an active state - to search for the meaning of life, move towards the spiritual component of life, because everything material has already been worked out - career, ambitions, family, children, and even the need of society.

There is only one thing left - the Supreme, the spiritual, the Divine. So, the virus is a messenger of the Supreme. Otherwise, how can one invite a person to the Highest for worldly affairs? Only through illness. If you don’t pay attention at a young age, in old age everything will catch up with you.

P.S. So, when working with a person, we always pay attention to his “colds” on the lips: something is happening with the meaning of life... something was passed on by the ancestors... This is important!

“The vast majority of organisms now living on Earth consist of cells, and only viruses do not have a cellular structure.

According to this most important feature, all living things are currently divided by scientists into two spheres:

precellular (viruses and phages),

cellular (all other organisms: bacteria and related groups, fungi, green plants, animals and humans).

Viruses are the smallest organisms, their sizes range from 12 to 500 nanometers. Viruses cannot be seen with an optical microscope because their sizes are smaller than the wavelength of light. They can only be seen using an electron microscope. Small viruses are equal to large protein molecules. The most important distinctive features of viruses are the following:

They do not have their own metabolism and have a very limited number of enzymes. For reproduction, the host cell's metabolism, enzymes and energy are used. Viruses, Satprem says, “harness the intelligence of cells.”

Nucleic acid is the carrier of the hereditary properties of the virus. Proteins of the inner and outer shells serve to protect it.

Since viruses do not have their own metabolism, outside the cell they exist in the form of “non-living” particles. In this case, we can say that viruses are inert crystals. When they enter a cell, they “come to life” again.

When reproducing, to create the components of their particles, viruses use nutrients, the information environment, and the energy-metabolic systems of the cells they infect. After penetration into the cell, the virus breaks down into its constituent parts - nucleic acid and envelope proteins. From this moment on, the biosynthetic processes of the host cell begin to be controlled by genetic information encoded in the nucleic acid of the virus.

In the host cell, the viral envelope and nucleic acid are synthesized separately. Subsequently, they combine and form a new virion (a fully formed mature virus).

Viruses do not reproduce on artificial nutrient media- They are too picky about food. They need living cells, and not just any cells, but strictly defined ones.

Science knows viruses of bacteria, plants, insects, animals and humans. In total there are more than a thousand of them. Processes associated with viral replication most often, but not always, damage and destroy the host cell. The reproduction of viruses, associated with the destruction of cells, leads to the occurrence of painful conditions in the body.

Viruses cause many human diseases: measles, mumps, influenza, polio, rabies, smallpox, yellow fever, trachoma, encephalitis, some cancers, AIDS, herpes.

Scientists are now increasingly suggesting that viruses are the cause of nervous disorders and mental illness. For example, Professor Norbert Nowotny from the University of Vienna has evidence that the Borna virus, which causes fatal brain diseases in animals, but does not pose a danger to humans, as previously thought, is still capable of infecting the human brain, causing schizophrenia, depression and chronic fatigue.

Borna virus is known to cause severe cases of brain inflammation in horses and sheep. As a result of the disease, animals stop eating, lose interest in their environment, and in most cases die from paralysis within 3 weeks.

Currently, there is no effective way to treat sick animals. Recent data suggest that the virus is still capable of causing certain changes in the human body, in particular, changes in the transmission of nerve signals that inevitably lead to mental disorders.

It has been shown that people suffering from nervous disorders have high levels of antibodies to the virus. In addition, the virus is also isolated from many people suffering from chronic fatigue syndrome.

Scientists have found that many viruses live in the human body, but they do not always manifest themselves. Only a weakened body is susceptible to the effects of a pathogenic virus.

There are various ways of infection by viruses: through the skin from insect and tick bites; through saliva, mucus and other secretions of the patient; through the air; with food; sexually and others.

There are a number of viruses known that are not carriers of diseases. Many of them penetrate the human body, but do not cause any clinically detectable diseases. They can exist for a long time and without any external manifestations in the cells of their host.

Otherwise, this would lead to the complete disappearance of the host as a biological species, and with it the pathogen itself. At the same time, any pathogenic organism will not be able to exist as a biological species if its main host develops immunity too quickly and effectively, allowing it to suppress the reproduction of the pathogen.

Therefore, a virus that causes an acute and severe disease in any species maintains the circulation of the virus in nature. For example, the rabies virus persists in nature among rodents, for which infection with this virus is not fatal.

For many viruses, such as measles, herpes and partly influenza, the main natural reservoir is humans. Transmission of these viruses occurs through airborne droplets or contact."published

Elena Romanova

P.S. And remember, just by changing your consumption, we are changing the world together! © econet

1 option

1. Cytoplasm performs functions

1). Provides turgor 2). Performs a protective function 3). Participates in the removal of substances

4). Location of cell organelles

2. Which picture shows a mitochondrion?

3. In ribosomes, unlike lysosomes,

1). Synthesis of carbohydrates 2) Synthesis of proteins 3). Oxidation of nucleic acids 4). Synthesis of lipids and carbohydrates

1). Oxidation of organic substances to inorganic ones2). Storage and transmission of hereditary information

3). Transport of organic and inorganic substances4). Formation of organic substances from inorganic ones using light

5. Which organelle takes part in cell division?

1). Cytoskeleton 2). Centriole 4) Cell center 5). Vacuole

6. In lysosomes, unlike ribosomes,

1). Synthesis of carbohydrates 2). Protein synthesis 3). Nutrient breakdown4). Synthesis of lipids and carbohydrates

7. Establish a correspondence between the structural features, function and organelle of the cell

A). There are smooth and rough membranes 1). Golgi complex

B). They form a network of branched channels and cavities 2). EPS

IN). Form flattened cisterns and vacuoles

G). Participates in the synthesis of proteins and fats

D). Form lysosomes

4). Participate in ATP synthesis

9. How does a plant cell differ from an animal cell?

Option 2

1. Transport of solids into the cell is called 1). Diffusion 2) Phagocytosis 3). Pinocytosis 4). Osmosis

2. Which picture shows a chloroplast?

3. The difference between an animal cell and a plant cell is

Presence of cellulose cell wall

Presence of a cell center in the cytoplasm

Presence of plastids

Presence of vacuoles filled with cell sap

4. Mitochondria in the cell perform the function

1). Oxidation of organic substances to inorganic ones 2). Storage and transmission of hereditary information

3). Transport of organic and inorganic substances 4). Formation of organic substances from inorganic ones using light

5. In lysosomes,unlike ribosomes occurs

1). Synthesis of carbohydrates 2). Protein synthesis 3). Nutrient breakdown 4). Synthesis of lipids and carbohydrates

6. Establish a correspondence between the structural features, function and organelle of the cell

Structural features, functions of Organoid

A). Contains chlorophyll pigment 1). Mitochondria

B). Carries out energy metabolism in the cell 2). Chloroplast

IN). Carries out the process of photosynthesis

G). The inner membrane forms folds - cristae

D). The main function is ATP synthesis

7. Choose three correct answers out of six

B2 Characterize the Golgi complex

1). Consists of a network of channels and cavities 2). Consists of tanks and bubbles 3). Lysosomes are formed

4). Participates in the packaging of substances 5) Participates in the synthesis of ATP 6). Participates in protein synthesis

8. . Describe chloroplasts? (three correct answers out of six)

1). Consists of flat tanks 2). It has a single-membrane structure 3). Contains its own DNA molecule

4). Participate in ATP synthesis

3). It has a double membrane structure 6). Chlorophyll is located on the grana

9. How is a plant cell different from an animal cell?

Test on the topic of viruses.

1. Viruses are:

2. Viruses reproduce:
D) do not reproduce at all

5. Please select multiple answers.

Viruses:

Test on the topic of viruses.

1. Viruses are:
A.) non-cellular life forms; B) the oldest eukaryotes; C) primitive bacteria D) primitive protozoa

2. Viruses reproduce:
A) independently outside the host cell; B) only in the host cell; C) A and BD) do not reproduce at all

3) The protein shell in which the virus is enclosed is called:
A) virion B) capsule C) viroid D) capsid

4 ) Viruses cause human disease - A) dysentery; B) sore throat; B) scabies; D) AIDS

5. Please select multiple answers.

Viruses:

3) are able to reproduce only inside animal cells 4) do not contain nucleic acids

5) can be destroyed by the use of antibiotics 6) are not capable of independent protein synthesis6. 1 option. What importance do viruses have in human life? Provide at least 2 values.

6. Option 2 AIDS prevention measures? (at least 2). Who is the causative agent of AIDS?

Test on the topic of viruses.

1. Viruses are:
A.) non-cellular life forms; B) the oldest eukaryotes; C) primitive bacteria D) primitive protozoa

2. Viruses reproduce:
A) independently outside the host cell; B) only in the host cell; C) A and BD) do not reproduce at all

3) The protein shell in which the virus is enclosed is called:
A) virion B) capsule C) viroid D) capsid

4 ) Viruses cause human disease - A) dysentery; B) sore throat; B) scabies; D) AIDS

5. Please select multiple answers.

Viruses:

3) are able to reproduce only inside animal cells 4) do not contain nucleic acids

5) can be destroyed by the use of antibiotics 6) are not capable of independent protein synthesis6. 1 option. What importance do viruses have in human life? Provide at least 2 values.

6. Option 2 AIDS prevention measures? (at least 2). Who is the causative agent of AIDS?

Test on the topic of viruses.

1. Viruses are:
A.) non-cellular life forms; B) the oldest eukaryotes; C) primitive bacteria D) primitive protozoa

2. Viruses reproduce:
A) independently outside the host cell; B) only in the host cell; C) A and BD) do not reproduce at all

3) The protein shell in which the virus is enclosed is called:
A) virion B) capsule C) viroid D) capsid

4 ) Viruses cause human disease - A) dysentery; B) sore throat; B) scabies; D) AIDS

5. Please select multiple answers.

Viruses:

3) are able to reproduce only inside animal cells 4) do not contain nucleic acids

5) can be destroyed by the use of antibiotics 6) are not capable of independent protein synthesis6. 1 option. What importance do viruses have in human life? Provide at least 2 values.

6. Option 2 AIDS prevention measures? (at least 2). Who is the causative agent of AIDS?

The virus integrates into the cell and becomes part of the person.

To kill the virus, you need to kill part of the person. Medicine treats the virus with drugs, and the virus feeds on energy, on humans.

A person swallows a pill, but he doesn’t stop thinking and feeling humiliated, lost, meaningless. The antiviral drug affects anything, just not thoughts.

To kill a virus, it is necessary to cure a person of the causes that create vibrations favorable to the life of the virus.

If a person does not change his attitude towards himself and the world, does not discover meanings that heal his self-esteem, melancholy, sadness, loss, the virus will live and prosper.

What can we say, old people are not in demand in society, and often they are not needed by their family and friends, so they have no joy in life at all. Add to this separation from the Divine, if a very old person is not a believer and does not experience unity with God. This is where the lurking herpes virus (shingles, Zoster) can roam. This is a very severe form, with serious pain.

There was no time to grieve and there was no strength left to grieve, only pain. I had to get active, get treatment, look for a way to recovery so that the virus would recede.

This is another unobvious task of the virus - to force the cell to become active. He lives at the expense of its resources, so in order for the cell to survive, it will need to be active or die... Through the cell, the virus pushes the entire organism to enter an active state - to look for the meaning of life, to move towards the spiritual component of life, because everything material has already been worked out - and career, and ambitions, and family, and children, and even the need of society. There is only one thing left - the Supreme, the spiritual, the Divine.

So, the virus is a messenger of the Supreme. Otherwise, how can one invite a person to the Highest for worldly affairs? Only through illness. If you don’t pay attention at a young age, in old age everything will catch up with you.

According to this most important feature, all living things are currently divided by scientists into two spheres:

precellular (viruses and phages),
cellular (all other organisms: bacteria and related groups, fungi, green plants, animals and humans).

“The vast majority of organisms now living on Earth consist of cells, and only viruses do not have a cellular structure.

Nucleic acid is the carrier of the hereditary properties of the virus. Proteins of the inner and outer shells serve to protect it.

The most primitive viruses consist of an RNA (or DNA) molecule surrounded on the outside by protein molecules that create the virus shell. Some viruses have another one - an outer, or secondary, shell; more complex viruses contain a number of enzymes. Since viruses do not have their own metabolism, outside the cell they exist in the form of “non-living” particles.

In the host cell, the viral envelope and nucleic acid are synthesized separately. Subsequently, they combine and form a new virion (a fully formed mature virus).

In this case, we can say that viruses are inert crystals. When they enter a cell, they “come to life” again.

Science knows viruses of bacteria, plants, insects, animals and humans. In total there are more than a thousand of them. Processes associated with viral replication most often, but not always, damage and destroy the host cell. The reproduction of viruses, associated with the destruction of cells, leads to the occurrence of painful conditions in the body.

Viruses cause many human diseases: measles, mumps, influenza, polio, rabies, smallpox, yellow fever, trachoma, encephalitis, some cancers, AIDS, herpes.

Currently, there is no effective way to treat sick animals. Recent data suggest that the virus is still capable of causing certain changes in the human body, in particular, changes in the transmission of nerve signals that inevitably lead to mental disorders.

Scientists have found that many viruses live in the human body, but they do not always manifest themselves. Only a weakened body is susceptible to the effects of a pathogenic virus.

The routes of infection by viruses are very different: through the skin through insect and tick bites; through saliva, mucus and other secretions of the patient; through the air; with food; sexually and others.

There are a number of viruses known that are not carriers of diseases. Many of them penetrate the human body, but do not cause any clinically detectable diseases. They can exist for a long time and without any external manifestations in the cells of their host.

Therefore, a virus that causes an acute and severe disease in any species maintains the circulation of the virus in nature.

For example, the rabies virus persists in nature among rodents, for which infection with this virus is not fatal.

For many viruses, such as measles, herpes and partly influenza, the main natural reservoir is humans. Transmission of these viruses occurs through airborne droplets or contact."

(305.9 kB)

Attention! Slide previews are for informational purposes only and may not represent all of the presentation's features. If you are interested in this work, please download the full version. Lesson objectives:

to form in students knowledge about a specific form of life - viruses, about the structural features of these life forms, the characteristics of their reproduction, scientific and practical significance. (Slide 2) Basic concepts:

virus, capsid. Means of education:

presentation (ITC), tables, popular science literature about viruses, student presentations.

During the classes

2. Repetition of material

Frontal conversation on the following issues:

1. What role do biocatalysts play in the cell?

2. What is the mechanism of action of enzymes?

3. What functions do DNA and RNA perform in a cell?

3. Studying new material.

As the presentation progresses, students must complete a “worksheet.”

2. Students report on infectious diseases (smallpox, influenza, AIDS).

1. History of the discovery of viruses

Diseases of plants, animals and humans, the viral nature of which has now been established, have caused enormous harm to human health and significant damage to the economy for many centuries. All attempts to find out the cause of these diseases and discover their causative agent remained unsuccessful.

For the first time, the existence of a virus - a new type of pathogens - was proved by the Russian scientist D.I. Ivanovsky. (Slide3)

DI. Ivanovsky

Dmitry Iosifovich Ivanovsky was born in 1864 in the St. Petersburg province. After graduating from high school with honors, in August 1883 he entered the Faculty of Physics and Mathematics at St. Petersburg University. As a needy student, Ivanovsky was exempt from paying tuition and received a scholarship.

Under the influence of outstanding scientists who taught at the university at that time (I.M. Sechenov, A.M. Butlerov, V.V. Dokuchaev, A.N. Beketov, A.S. Famitsin and others), the worldview of the future scientist was formed . As a student, Ivanovsky enthusiastically worked in a scientific biological circle, conducted experiments on the anatomy and physiology of plants, carefully performing experiments. Therefore, A.N. Beketov, who then headed the society of naturalists, and Professor A.S. Famitsin suggested in 1887 that students D.I. Ivanovsky and V.V. Polovtsev go to Ukraine and Bessarabia to study the tobacco disease, which was causing enormous damage to the agricultural sector. economy of the south of Russia. The tobacco leaves were covered with a complex abstract design, sections of which flowed like ink on a blotter and spread from plant to plant.

The end of the 19th century was marked by major advances in microbiology, and, naturally, Ivanovsky decided to find out whether some bacterium causes tobacco mosaic. He examined many diseased leaves under an optical microscope (there were no electronic ones yet) but in vain - no signs of bacteria could be found. “Or maybe they are so small that they cannot be seen?” - thought the scientist. If this is the case, then they must pass through filters that trap common bacteria on their surface. Similar filters already existed at that time.

Ivanovsky placed a finely ground leaf of diseased tobacco into the liquid, which he then filtered. Bacteria were retained by the filter, and the filtered liquid had to be sterile and not capable of infecting a healthy plant if it came into contact with it. But she was infectious! This is the essence of Ivanovsky’s discovery (how simple everything is brilliant!).

This is where the difference in size comes into play. Viruses are approximately 100 times smaller than bacteria, so they freely passed through all the filters and infected healthy plants, falling on them along with the filtered liquid. Bacteria are also distinguished by their ability to reproduce in artificially created nutrient media, but the viruses discovered by Ivanovsky did not do this. “So this is something new,” the scientist decided. The year was 1892.

The causative agent of mosaic disease is called Ivanovsky either by “filterable” bacteria or microorganisms. And this is understandable, since it was very difficult to immediately formulate the existence of a special world of viruses. The term virus (from the Latin virus - poison) appeared later.

This is how Ivanovsky discovered viruses - a new form of existence of life. With his further research, he laid the foundations for a number of scientific directions in virology.

The first half of the twentieth century truly turned out to be an era of great virological discoveries. The causative agents of acute febrile diseases were especially closely studied. Methods for combating them and measures to prevent these diseases were developed. The desire of scientists to detect and isolate the virus as soon as possible in any unknown and particularly severe disease is quite understandable and justified, since the first step in the fight against the disease is to find out its cause.

Having studied the properties of the isolated virus, scientists began to prepare an antidote - a vaccine, and then directly to the treatment and prevention of the disease. Thus, in the struggle for human health and life, the young science of viruses - virology - emerged.

Viruses

Viruses (from the Latin poison) do not have a cellular structure. They represent the simplest form of life on our planet, occupying a borderline position between inanimate and living matter. (slide 4)

Viruses differ from inanimate matter in two properties: the ability to reproduce similar forms (multiply) and the possession of heredity and variability.

Viruses are designed very simply. Each viral particle consists of RNA or DNA enclosed in a protein shell called a capsid.

Having penetrated the cell, the virus changes its metabolism, directing all its activity to the production of viral nucleic acid and viral proteins. Inside the cell, self-assembly of viral particles from synthesized nucleic acid molecules and proteins occurs. Before death, a huge number of viral particles manage to be synthesized in the cell. Ultimately, the cell dies, its shell bursts and the viruses leave the cell.

By settling in the cells of living organisms, viruses cause many dangerous diseases: in humans - influenza, smallpox, measles, polio, mumps, rabies, AIDS; in plants – mosaic disease of tobacco, tomatoes, cucumbers, leaf curl, dwarfism; in animals - foot and mouth disease, swine and bird plague, infectious anemia of horses.

What is a virus?

The vast majority of organisms living on Earth today consist of cells, and only viruses do not have a cellular structure. (slide 5)

According to this most important feature, all living things are currently divided by scientists into two empires:

Precellular (viruses and phages),

Cellular (all other organisms: bacteria and related groups, fungi, green plants, animals and humans).

The most important distinctive features of viruses are the following:

2. They do not have their own metabolism and have a very limited number of enzymes. For reproduction, the host cell's metabolism, enzymes and energy are used.

Nucleic acid (NA) is the carrier of the hereditary properties of the virus. Proteins of the inner and outer shells serve to protect it.

When reproducing, viruses use nutrients and the energy-metabolic systems of the cells they infect to create the components of their particles. After penetration into the cell, the virus breaks down into its constituent parts - NK and envelope proteins ("undresses"). From this moment on, the biosynthetic processes of the host cell begin to be controlled by genetic information encoded in the nucleic acid of the virus.

Science knows viruses of bacteria, plants, insects, animals and humans. There are more than 1000 of them. Processes associated with the reproduction of the virus most often, but not always, damage and destroy the host cell. The reproduction of viruses, associated with the destruction of cells, leads to the occurrence of painful conditions in the body.

Viruses cause many human diseases: measles, mumps, influenza, polio (slide 6), rabies, smallpox, yellow fever, trachoma, encephalitis, some oncological (tumor) diseases, AIDS. It is not uncommon for people to start growing warts. Everyone knows how, after a cold, they often “sweep” the lips and wings of the nose. These are also all viral diseases.

Scientists have found that many viruses live in the human body, but they do not always manifest themselves. Only a weakened body is susceptible to the effects of a pathogenic virus.

In animals, viruses cause foot and mouth disease, plague, and rabies; in plants - mosaic or other changes in the color of leaves or flowers, leaf curl and other changes in shape, dwarfism; finally, in bacteria - their decay.

From the very beginning, viruses were considered only pathogens. The idea of viruses as exclusively pathogenic agents still prevails in wide circles of the “uninitiated.” However, this is not entirely true.

Structure of viruses

Viruses cannot be seen with an optical microscope because their sizes are smaller than the wavelength of light. They can only be seen using an electron microscope. (slide 7)

Viruses consist of the following main components:

1. Core - genetic material (DNA or RNA), which carries information about several types of proteins necessary for the formation of a new virus.

2. The protein shell, which is called the capsid (from the Latin capsa - box). It is often built from identical repeating subunits - capsomeres. Capsomeres form structures with a high degree of symmetry.

3. Additional lipoprotein membrane. It is formed from the plasma membrane of the host cell and is found only in relatively large viruses (influenza, herpes).

The capsid and the additional shell have protective functions, as if protecting the nucleic acid. In addition, they facilitate the penetration of the virus into the cell. A fully formed virus is called a virion. (Slide 8)

Rice. 2. Schematic structure of the virus: 1 - core (single-stranded RNA); 2 - protein shell (capsid); 3 - additional lipoprotein membrane; 4 - capsomeres (structural parts of the capsid).

The number of capsomeres and the way they are folded are strictly constant for each type of virus. For example, the polio virus contains 32 capsomeres, and the adenovirus contains 252.

Since the basis of all living things is genetic structures, viruses are now classified according to the characteristics of their hereditary substance - nucleic acids. All viruses are divided into two large groups: DNA-containing viruses (deoxyviruses) and RNA-containing viruses (riboviruses). Each of these groups is then divided into double-stranded and single-stranded nucleic acid viruses. The next criterion is the type of virion symmetry (depending on the way capsomeres are laid), the presence or absence of outer shells, etc.

Schematic representation of the arrangement of capsomeres in the viral capsid. (slide 6) The influenza virus has a spiral type of symmetry - A. Cubic type of symmetry in viruses: herpes - b, adenovirus - V, polio - G.

Characteristic features of viruses (slide 9)

Similarities with living organisms	Difference from living organisms	Specific features
Ability to reproduce.	1. In the external environment they have the form of crystals, without showing any properties of living things.	1.Very small sizes.
Heredity	2. They do not consume food.	2.Ease of organization (nucleic acids + protein)
3.Variability.	3.Do not produce energy.	3. They occupy a borderline position between inanimate and living matter.
4. Characterized by adaptability to changing environmental conditions.	4. They don’t grow.	4.High reproduction rate.
	5. No metabolism	5. Carrier of hereditary information.
	6.Have a non-cellular structure.

1. Viral infections.

The entry of viruses into the body of a person, animal or bird does not always cause the development of acute infections. Viruses can exist for a long time and without any external manifestations in the cells of their host. This occurs in cases where the antiviral antibodies produced by the body do not completely destroy the virus, but restrain its reproduction within the framework of “peaceful coexistence.” Such an alliance is beneficial to both parties. (Slide 10)

The longer the truce lasts, the longer it takes for the body to produce antibodies. In this situation, there is no danger of infecting the body from the outside with a more active virus, and therefore the development of an acute infection is impossible.

As part of “peaceful coexistence,” the virus continues to multiply in the host’s body, as a result of which the latter, through its external secretions, contributes to the spread of the virus in the biosphere. In this case, the host organism is a carrier of a latent (from the Latin latens - hidden) viral infection.

2. Student reports about infectious diseases

In those days, when humanity still had no idea about viruses, the terrible diseases caused by them forced us to look for ways to get rid of these diseases. A striking example of this is the fight against smallpox. (slide 11).

Smallpox is one of the oldest diseases. In the past, it was the most common and most dangerous disease.

A description of smallpox was found in the Egyptian papyrus of Amenophis I, compiled 4 thousand years BC. Smallpox lesions were preserved on the skin of a mummy buried in Egypt 3000 BC. In the 16th - 18th centuries in Western Europe, in some years, up to 12 million people fell ill with smallpox, of whom up to 1.5 million died. Smallpox affected 2/3 of the children born at that time, and out of eight who fell ill with it, three died. A special sign was then considered: “It has no signs of smallpox.” People with smooth skin, without smallpox scars, were rare in those days. Now it’s even difficult for us to imagine the crushing force with which the smallpox virus wielded itself back then.

Ultimately, this ancient scourge of humanity was broken by science. Now the smallpox epidemics have stopped.

Even 3,500 years ago in Ancient China, it was noticed that people who had suffered a mild form of smallpox never got sick with it again. Later (more than 1000 years ago), fearing a severe form of this disease, which not only brought with it inevitable disfigurement of the face, but often death, residents of China, India and Persia began to artificially infect children with smallpox.

Some wore shirts of patients whose illness was mild. Crushed and dried smallpox crusts were blown into the noses of others. Finally, smallpox was “bought” - the child was taken to the patient with a coin held tightly in his hand, in return he received several crusts from smallpox pustules, which he had to squeeze tightly in the same hand on the way home. A person infected with smallpox in this way tolerated it much easier.

The problem of preventing smallpox was solved only at the end of the 18th century by the English country doctor Edward Jenner. He was not the first to draw attention to the fact that people who had cowpox (a disease of cattle, which usually occurs easily in humans) subsequently never contracted smallpox. But it was Jenner who, based on these observations, drew the correct conclusions, clearly formulated his theory and, as a result of persistent and systematic work, came to the most important discovery.

In early May 1796, he had to treat milkmaid Sarah Selmes, who had pustules typical of cowpox on her arm. On May 14, Jenner introduced liquid from the pustules of a sick milkmaid into the wound on the shoulder of an eight-year-old boy, James Phipps, who had not previously suffered from smallpox. At the site of the artificial infection, the boy developed typical pustules, which disappeared after 14 days. On July 1, Jenner introduced highly infectious material from the pustules of a smallpox patient into a scratch on James' skin... And the boy remained healthy.

This is how the idea of vaccination by vaccination (from the Latin vassa - cow) was born and confirmed. Vaccination is the introduction of cowpox infectious material into the human body in order to protect it from smallpox. The vaccine is the substance itself that protects against smallpox. Nowadays, the words “vaccination” and “vaccine” are used as general terms denoting vaccination and vaccination material.

Jenner was the first to prove that through vaccination it is possible to suppress the spread of infectious diseases and banish them from the face of the Earth. At the same time, he had no idea about the nature of the causative agent of the disease itself! He was guided only by brilliant intuition and the talent of an observant researcher.

The causative agent of smallpox is a large (300-350 nanometers), complex DNA-containing virus that multiplies in the cytoplasm of cells. It has a cuboidal shape. Smallpox virions have a lipoprotein shell, under which there is viroplasm, which contains the nucleocapsid. The DNA of the smallpox virus is double-stranded. Some enzymes have been isolated from the virion nucleocapsid.

The source of infection is sick people. Infection is spread by airborne droplets and airborne dust (the virus is transmitted by talking, coughing, through dishes, as well as through dust particles on clothing) (slide 12).

Smallpox viruses enter the human body through the mucous membrane of the respiratory tract and skin and are localized in the lymph nodes. Having multiplied there, they enter the blood. Secondary reproduction (reproduction) occurs in lymphoid tissue and is accompanied by clinical manifestations of the disease: high fever, headache, loss of consciousness. Papules, vesicles and pustules form on the skin and mucous membranes. Smallpox papules are characterized by transparent contents and have the appearance of pearls with a pearlescent sheen. After healing, scars remain at the site where the pustules appear. The formation of scars on the mucous membrane of the eyes leads to blindness (in 25% of cases).

The mortality rate for smallpox is high, for the hemorrhagic form - 100%. In this form, the pustules fill with blood - black pox. Mild forms of smallpox occur when the disease occurs without fever or rash.

Small and cattle are sensitive to the smallpox virus. Under experimental conditions, monkeys, guinea pigs, rabbits, etc. are easily infected. However, the disease, which is clinically similar to the human disease, can only be reproduced in monkeys.

People who have recovered from smallpox develop lifelong immunity. Artificial immunization followed by revaccination also provides lasting immunity.

The need for timely vaccination against smallpox is eloquently demonstrated by the figures below:

The baby is given a smallpox vaccination, which he tolerates easily. Immunity is developed for 7 years (left). The entire body of a smallpox patient is covered with smallpox scabs (right). Everyone is urgently scheduled for vaccination

Prevention of smallpox is early diagnosis, isolation of patients, disinfection, prevention of the importation of smallpox from other countries, quarantine.

At a temperature of 100° C, smallpox viruses die instantly. A temperature of 60°C kills them within an hour. Smallpox viruses tolerate low temperatures and drying well; smallpox crusts persist for a long time.

Influenza, according to our standards, is not such a serious disease, but it remains the “king” of epidemics. None of the diseases known today can cover hundreds of millions of people in a short time, and more than 2.5 billion people fell ill with the flu in just one pandemic (widespread epidemic)!.. (slide 13).

In 1918, a flu pandemic called the Spanish Flu broke out. The disease was accompanied by a kind of “cyanosis” caused by severe oxygen starvation caused by malignant pneumonia. Within a year and a half, the epidemic spread to all countries of the world, affecting more than a billion people. The disease was extremely difficult: about 25 million people died - more than from injuries on all fronts of the First World War in four years. Never since has influenza caused such a high mortality rate.

Mass vaccinations against influenza, which were practiced in the 50s of the twentieth century here and in the USA, led to unexpectedly modest and even more than modest results. Vaccination reduced the incidence of the disease by one and a half to two times, and in some years its effectiveness was zero. The immunity acquired in a person after the introduction of an influenza vaccine in most cases could not resist the next outbreak of the disease.

Every major influenza epidemic is caused by a new variant, a new variety. Each time the flu virus comes out in different clothes. And this is not a figurative comparison, not a metaphor. Indeed, influenza viruses often change their clothes.

The influenza virus was discovered in 1933. The virions isolated then are still preserved in laboratories and are designated by the symbol H 0 N 1 (hemagglutinin H 0, neuraminidase N 1).

In 1947, a major influenza epidemic began. It was caused by a new variant of the virus - H 1 N 1: neuraminidase remained the same, but hemagglutinin changed. The "Asian" flu pandemic in 1957 was caused by a virus in which both proteins were changed - its formula H 2 N 2. The "Hong Kong" virus that caused the 1968 pandemic changed its hemagglutinin - its formula is H 3 N 2.

Where do new influenza virus proteins come from? There is no clear answer to this question yet. But there is a guess.

Influenza viruses affect not only humans, but also animals. Yes, and they were discovered first in animals, and only then in humans. In 1932 (a year before the discovery of the human influenza virus), a similar virus was isolated from pigs. Then more and more new animal influenza viruses, similar to human viruses, began to be discovered. They were isolated from pigs, horses, dogs, calves and many species of domestic and wild birds.

For example, the human Hong Kong influenza virus appeared in 1968. And 4-5 years earlier, two influenza viruses were discovered - a duck influenza virus in Ukraine and a horse influenza virus in the USA, in which the hemagglutinin is similar to the hemagglutinin of the "Hong Kong" virus. So, the human virus appeared in 1968, and its proteins were already present in similar animal viruses...

Thus, data began to accumulate on the circulation of influenza viruses among humans and animals.

When will the flu be defeated? Probably not anytime soon. Then, when we learn to monitor his “changing clothes”, we will learn to predict where he “dives” and in what form he “emerges”, when we learn to meet the reincarnated virus with the entire arsenal of possible means against his new clothes. But...

In 1977, the H1N1 virus, which had disappeared in 1957, reappeared after an absence of 20 years. It is still unclear why it disappeared 20 years ago and why it reappeared. One can only assume that either it was preserved, circulating among animals, or was again synthesized as a result of recombination processes. However, something else is important: the reappearance of a similar virus indicates that the number of influenza viruses epidemically dangerous to humans is limited. This means that a universal flu vaccine may not be far off. In the meantime, there is a lot of painstaking work ahead, similar to the work of a criminologist who patiently pursues a criminal who leaves subtle and not always clear traces of his transformations.

The source of influenza infection is a sick person. Usually, infection is transmitted by airborne droplets through direct contact with a patient (by talking, coughing, sneezing) (slide 14).

The influenza virus, entering the mucous membrane of the upper respiratory tract, penetrates into their epithelial cells. From there it passes into the blood and causes intoxication (poisoning). In the mucous membrane, the virus causes cell death. This creates conditions for the activation of various pathogenic bacteria localized in the upper respiratory tract, as well as for the penetration of other microorganisms that cause secondary infection - pneumonia, bronchitis. In addition, the influenza virus activates chronic diseases, such as tuberculosis.

A temperature of 65° C kills the influenza virus in 5-10 minutes. In acidic and alkaline environments, under the influence of ether and disinfectant solutions, it dies quickly. The virus is very sensitive to ultraviolet rays and ultrasound, but is resistant to glycerol, in which it can survive for several months.

Of great importance in the prevention of influenza is hardening the body, timely isolation of the patient, wet cleaning of premises and their ventilation.

AIDS

Acquired immune deficiency syndrome (AIDS) is a relatively new, but very terrible infectious disease that arose before humanity at the very end of the 2nd millennium. It is no coincidence that it is also called the “plague of the twentieth century.” (slide15)

But neither the plague, nor smallpox, nor cholera are precedents, since AIDS is decidedly unlike any of these and other known human diseases. The plague claimed tens of thousands of lives in the regions where the epidemic broke out, but never covered the entire planet at once. In addition, some people, having been ill with it, survived, acquiring immunity, and took upon themselves the work of caring for the sick and restoring the damaged economy.

Leading experts define AIDS as a “global health crisis”, which by and large is not yet controlled by medicine and every person infected with it dies from it. The average life expectancy of an HIV-infected person is 7-10 years.

The first people with AIDS were identified in 1981. At first, the spread of the virus that caused this disease occurred mainly among certain groups of the population, which were called risk groups. These are drug addicts, prostitutes, homosexuals, patients with congenital hemophilia, since the life of the latter depends on the systematic administration of drugs from donor blood. However, then the AIDS virus spread beyond these groups and began to infect the general population.

By 1991, AIDS was reported in every country in the world except Albania. In the United States, already at that time, one out of every 100-200 people was infected, every 13 seconds another person became infected with this disease, and by the end of 1991, AIDS in this country had become the third leading cause of death, surpassing cancer.

The “Plague of the 20th Century” initially spared our country. However, Russia has now taken one of the first places in the world in terms of the rate of increase in the number of HIV-infected people. If in less than 9 months of 1999, 12,134 new cases of HIV infection were registered among our citizens, then for the same period in 2000 - 30,160 (an increase of 248.6%). According to the Russian Scientific and Methodological Center for the Prevention and Control of AIDS, from January 1987 to October 2000, 610,270 HIV-infected Russian citizens were registered. Of these, 624 people died.

The causative agent of AIDS is the human immunodeficiency virus (HIV). HIV is characterized by extreme variability - it is 30-100, and according to some sources, a million times higher than that of the influenza virus. It concerns not only strains of the virus isolated from different patients, but also those isolated at different times of the year from the same patient. This property greatly complicates the possibility of obtaining vaccines against HIV.

As you know, the immune system ensures the constancy of the composition of proteins in our body and fights infections and malignantly degenerating cells of the body.

A special feature of HIV is its ability to penetrate the cells of the immune system and destroy them during its reproduction. This leads to a breakdown of the entire human immune system, as a result of which the body loses its protective properties and is unable to resist pathogens of various infections and kill tumor cells.

In such a situation, when a secondary infection enters the body, the latter does not meet adequate resistance from the weakened human immune system, and the disease develops rapidly. The only end result so far is death.

The source of HIV infection is a person infected with this virus. The AIDS virus is usually transmitted:

With blood,

During sexual intercourse,

In 50% of cases, the fetus is born in the womb of an infected mother.

Traditionally, it was believed that out of 10 cases of infection, in 7 cases HIV was transmitted through sexual contact, in 2 cases the “dirty” syringes of drug addicts were to blame, and only in one case was it caused by medical workers.

However, since the summer of 1996, there has been a “collapse” among drug addicts: they now make up two thirds of Russian citizens with AIDS. This is explained by the fact that infection occurs not only when drug addicts use a common syringe and needle, but also due to the presence of the virus in the “ready” drug solution.

In 1997, quite cheap drugs began to arrive in Russia in solution - so to speak, already ready for use (ordinary Pepsi-Cola bottles were used for the container). This solution should have a pH approximately equal to the pH of blood. Otherwise, when administered intravenously, the blood will inevitably clot, leading to instant death. In such a solution of the drug, the virus received a “registration warrant”, and the “Pepsi generation” gave an unprecedented jump in HIV infection.

As noted above, only one out of 10 infections now occurs through medical transmission of HIV infection: through hospital instruments or through blood transfusions during surgical operations. Although this route of infection is the least likely, it is still the most dangerous for normal people. After all, the majority of them are not drug addicts, have a limited number of sexual contacts (at least they use condoms), but anyone can end up in the hospital!

However, Russian experts unanimously insist: after the sad events of 1988 in Elista, when children were infected due to unsterile drip systems, domestic healthcare received a severe lesson, and since then no hospital infections of citizens with AIDS have been recorded. But there are cases of infection with the virus through donated blood during operations.

What do we need to do to defeat the “plague of the twentieth century”?

The first priority is to protect the blood bank. All blood must be monitored with high-quality, latest test systems.

Only serious daily preventive work can save the already existing unfavorable situation from further deterioration. Doctors must “go to the people”: provide everyone with the necessary knowledge, talk about AIDS as much as possible in the media. Teachers and parents must join the doctors.

It is necessary to explain to young people, especially teenagers, the importance of safe sex using condoms. Don't forget: condoms are a powerful barrier to the spread of HIV infection. It's verified!

Intravenous drug use should be avoided, as it is not only harmful to health, but also significantly increases the possibility of contracting the virus.

It is necessary to rely on the most modern methods of treatment, as there is a ray of hope here. At the XI World AIDS Conference, which took place in 1997 in Vancouver (Canada), scientists first announced the stunning success of combination therapy in the fight against HIV. We are talking about tritherapy by American doctor David Ho. The use of this technique leads to a decrease in the content of the AIDS virus in the patient’s blood to zero, and the patient ceases to be infectious to others. Think about it: this is a new quality level! True, it is too early to talk about complete healing: the virus still persists in the lymph nodes and tissues, so the person himself continues to get sick.

Teacher's final words

Based on all that has been said, we can conclude that viruses, although they do not have a cellular structure, belong to living organisms. In this regard, all living things are divided into two empires - precellular, which unites viruses and bacteriophages, and cellular (kingdoms of plants, animals, fungi and prokaryotes), (slide 16)

Summarizing and consolidating the studied material in the process of checking the correctness of filling out the “worksheets”.

Homework: prepare for a test and general lesson on the topic “Molecular level”. Create a crossword puzzle of 10 questions on the topic “Viruses”.

Class student worksheet.

Viruses were discovered in…………. year of scientists…………………………

Viruses do not have …………………………………………………………..

The “heart” of the virus consists of………………….or……………………..

The protein shell of the virus is called……………………………………

Many viruses have the form……………………………………………..

By way of life, viruses are………………………………………..

Viruses can only show signs of a living organism when they are in………..

Infectious diseases include……………………………………….

Viruses were discovered by D.I. Ivanovsky (1892, tobacco mosaic virus).

If viruses are isolated in their pure form, then they exist in the form of crystals (they do not have their own metabolism, reproduction and other properties of living things). Because of this, many scientists consider viruses to be an intermediate stage between living and nonliving objects.

Viruses are non-cellular life forms. Viral particles (virions) are not cells:

viruses are much smaller than cells;
viruses are much simpler in structure than cells - they consist only of nucleic acid and a protein shell, consisting of many identical protein molecules.
viruses contain either DNA or RNA.

Synthesis of virus components:

The nucleic acid of the virus contains information about viral proteins. The cell makes these proteins itself, on its ribosomes.
The cell reproduces the nucleic acid of the virus itself, with the help of its enzymes.
Then the self-assembly of viral particles occurs.

Virus meaning:

cause infectious diseases (flu, herpes, AIDS, etc.)
Some viruses can insert their DNA into the chromosomes of the host cell, causing mutations.

AIDS

The AIDS virus is very unstable and is easily destroyed in the air. You can become infected with it only through sexual intercourse without a condom and through a transfusion of contaminated blood.

Answer

Establish a correspondence between the characteristics of a biological object and the object to which this characteristic belongs: 1) bacteriophage, 2) E. coli. Write numbers 1 and 2 in the correct order.
A) consists of nucleic acid and capsid
B) cell wall made of murein
C) outside the body is in the form of crystals
D) can be in symbiosis with humans
D) has ribosomes
E) has a tail canal

Answer

Choose one, the most correct option. Science studies precellular life forms
1) virology
2) mycology
3) bacteriology
4) histology

Answer

Choose one, the most correct option. The AIDS virus infects human blood
1) red blood cells
2) platelets
3) lymphocytes
4) blood platelets

Answer

Choose one, the most correct option. The cells of which organisms are affected by the bacteriophage?
1) lichens
2) mushrooms
3) prokaryote
4) protozoa

Answer

Choose one, the most correct option. The immunodeficiency virus primarily affects
1) red blood cells
2) platelets
3) phagocytes
4) lymphocytes

Answer

Choose one, the most correct option. In what environment does the AIDS virus usually die?
1) in the lymph
2) in breast milk
3) in saliva
4) in the air

Answer

Choose one, the most correct option. Viruses have such signs of living things as
1) food
2) growth
3) metabolism
4) heredity

Answer

1. Establish the correct sequence of stages of reproduction of DNA viruses. Write down the corresponding sequence of numbers in the table.
1) release of the virus into the environment
2) virus protein synthesis in the cell
3) introduction of DNA into the cell
4) synthesis of viral DNA in the cell
5) attachment of the virus to the cell

Answer

2. Establish the sequence of stages of the bacteriophage life cycle. Write down the corresponding sequence of numbers.
1) biosynthesis of DNA and bacteriophage proteins by a bacterial cell
2) rupture of the bacterial shell, release of bacteriophages and infection of new bacterial cells
3) penetration of bacteriophage DNA into the cell and its integration into the circular DNA of the bacterium
4) attachment of the bacteriophage to the bacterial cell membrane
5) assembly of new bacteriophages

Answer

1) have an unformed core
2) reproduce only in other cells
3) do not have membrane organelles
4) carry out chemosynthesis
5) capable of crystallizing
6) formed by a protein shell and nucleic acid

Answer

Choose three correct answers out of six and write down the numbers under which they are indicated. Viruses as opposed to bacteria
1) have a cellular structure
2) have an unformed core
3) formed by a protein shell and nucleic acid
4) belong to free-living forms
5) reproduce only in other cells
6) are a non-cellular form of life

Answer

1. Establish a correspondence between the characteristic of an organism and the group for which it is characteristic: 1) prokaryotes, 2) viruses.
A) cellular structure of the body
B) the presence of its own metabolism
C) integration of one’s own DNA into the DNA of the host cell
D) consists of a nucleic acid and a protein shell
D) reproduction by division in two
E) the ability to reverse transcription

Answer