Presentation on the topic of viruses and cell-free organisms. Presentation on the topic viruses - non-cellular life forms. Diseases caused by viruses

Diversity of living organisms.

Cellular and

non-cellular life forms

Teacher

Z. M. Smirnova

Modern system organisms

Empire

Cellular organisms

Pre-nuclear

Overkingdoms

Kingdoms

(prokaryotes)

Drobyanki

Nuclear (eukaryotes)

Mushrooms

Non-cellular organisms

Sub-kingdoms

Grow

Animals

Viruses

Vira

Cyanobacteria or (blue-green algae)

Eubacteria

viruses

Diversity of the organic world

Empire Cellular

Empire Noncellular

Plant Kingdom

Kingdom Mushrooms

Animal Kingdom

Kingdom Viruses

Multicellular

Eukaryotes

Subkingdom Protozoa

Unicellular

Prokaryotes

Kingdom of Drobyanka

Types of Cellular Organization

Eukaryotic

includes the superkingdom Eukaryotes.

Have a formed core

and a well-developed internal membrane system. The genetic apparatus is represented by molecules DNA in complex with proteins - histones that package DNA into nucleosomes.

Prokaryotic

includes the superkingdom of Prokaryotes.

Do not have a formal core

and membrane organelles. Genetic material - circular DNA molecule (nucleoid).

DNA is not blocked by proteins, therefore all genes in it are active.

Overkingdom Prokaryotes

Structural and functional parts of a prokaryotic cell:

• Cytoplasm

• Surface

• Genetic

material:

device:

• nucleoid – zone

• plasmatic

cytoplasm with large

membrane;

molecule

Supramembrane

DNA, closed

complex:

in the ring

• mureic

cell wall (complex carbohydrate);

• plasmids –

• mucous capsule

short

ring

(performs

protective function)

DNA molecules

• flagella

Cytoplasmic structures:

Hyaloplasm:

• mesosomes

• sol (in favorable

conditions)

(invaginations

• gel (with

plasmatic

bad

membranes)

conditions,

• membrane

When

organoids

increases

are missing, their

perform the function

density

hyaloplasma)

mesosomes.

• ribosomes (small)
• cytoplasm

motionless, because

microtubules

are missing.

Overkingdom Eukaryotes

Structural and functional parts of a eukaryotic cell:

Surface

apparatus

Cytoplasm

Core

• nucleoli
• chromosomes
• karyoplasm

hyaloplasm

plasmalemma

(proteins,

lipids)

submembrane complex

(accumulation of microtubules and microfilaments of the cytoskeleton under the plasmalemma)

cytoplasmic

logical structures

(organelles and

inclusions)

supramembrane complex

(in an animal cell – glycocalyx,

in a plant cell – cell wall (cellulose),

mushrooms - chitin)

Comparison of pro- and eukaryotic organisms

PROKARYOTES

Cell size

EUKARYOTES

1-10 µm

Metabolism

10-100 microns

Anaerobic or aerobic

Aerobic

Organelles

Not numerous (membrane invaginations - mesosomes and small ribosomes).

Cytoplasm

Nucleus, mitochondria, chloroplasts, endoplasmic reticulum, etc.

Circular DNA in the cytoplasm (nucleoid)

DNA – organized into chromosomes and surrounded by a nuclear membrane

Absence of cytoskeleton, cytoplasmic movement, endo- and exocytosis

Cell division, cellular organization

There is a cytoskeleton, cytoplasmic movement, endocytosis and exocytosis

Binary fission, predominantly unicellular and colonial

Mitosis (or meiosis), predominantly multicellular

Non-cellular life forms

Viruses were discovered by D.I. Ivanovsky (1892) while studying tobacco mosaic disease.

I. D. Ivanovsky

Tobacco mosaic virus

The place of viruses in the system of living nature

Empire Non-cellular life forms

Kingdom of Vir

Size comparison

1/10 part of a red blood cell

Bacteriophage

(eukaryote-

cheskaya

cell)

Adenovirus 90 nm

Tobacco mosaic virus

250 x 18 nm

Rhinovirus

Prion

200 x 20 nm

E. Coli (bacterium - Escherichia coli)

3000 x 1000 nm

Routes of entry into the human body:

- by airborne droplets from a sick person (flu, measles, smallpox);

- with food (foot-and-mouth disease virus);

- through damaged skin surface (rabies, herpes, smallpox);

- sexually (HIV, herpes);

- through blood-sucking (mosquitoes - yellow fever, ticks - encephalitis, Crimean fever);

- during blood transfusions and operations, the AIDS and hepatitis B viruses are transmitted.

Plant cells are affected as a result of violation integrity of integument

Life forms of the virus

There are two life forms of viruses

Intracellular

– inside infected cell with viruses manifest themselves in the form of nucleic acid (DNA or RNA) and form a “virus-cell” complex capable of living and “producing” new

virions.

Extracellular (resting) – viral particles, or virions, consisting of nucleic acid and

capsid (shell made of protein and, less commonly, lipids).

The virion is essentially conglomerate of organic crystals.

Virion structure:

Core – genetic material

(DNA or RNA)

Shell

Complex viruses

Simple viruses have a shell

• capsid, consisting only of protein subunits - capsomeres

(flu, herpes, etc.)

have supercapsid :

• capsid,
• outside two layers

lipids (Part

plasmatic

membranes

host cells

• viral

glycoproteins

• non-structural

proteins - enzymes

Virus

tobacco mosaic

Features of the life activity of viruses:

Variety of shapes and sizes of viruses

(10 to 300 nm)

Plant viruses

(usually contain RNA);

Animal viruses;

• Precipitation;
• Penetration of the virus into the cell:

fusion of the virus membrane and the outer membrane occurs cytoplasmic membrane - the virus ends up in cytoplasm of the cell.

Stages of the life of the virus

3. Destruction of viral protein shells.

Lysosome enzymes destroy the capsid virus and its nucleic acid freed up.

4. Synthesis of DNA with RNA virus.

5. Incorporation of viral DNA into cell DNA.

Functioning is suppressed genetic apparatus of the cell.

Stages of the life of the virus

6. Nucleic acid replication

acids of the virus.

7. Synthesis of capsid proteins. After replication, the biosynthesis of viral capsid proteins begins, using the ribosomes of the host cell.

8. Virion assembly

Begins with the accumulation of viral proteins and RNA

9. Exit of viruses from the cell

Complex viruses leaving the cell capture part of the cell membrane host cells and form a supercapsid.

HIV infection

HIV infection is a slowly progressive disease, characterized by damage to cells of the immune system (lymphocytes, etc.) with the development of immunodeficiency (AIDS) - the body is unable to resist pathogens of various infections and malignant neoplasms.

IN – virus

AND – immunodeficiency

H – person

WITH – syndrome (complex of symptoms)

P – acquired (not congenital condition)

AND – immuno-

D – deficiency (the body loses the ability

resist various infections)

AIDS is the final, terminal stage of HIV infection

Viruses and diseases they cause

Virus conjunctivitis,

pharyngitis

Adenoviruses

Rubella

Rubella virus

Human papillomavirus

Warts, genital papillomas

Flu

Orthomyxoviruses

Poliomyelitis, meningitis, ARVI

Picornavirus

Hepatotropic viruses

Viral hepatitis

HIV – infection, T-cell leukemia – adult lymphoma

Retroviruses

Herpes simplex, chicken pox, shingles

Herpesviruses

Poxviruses

Smallpox

Herpes virus

Influenza virus

• Structure:

• head containing nucleic acid acid,

capsid covering the head;

• hollow rod (tail) with

protein cover;

• tail filaments

Reproduction of bacteriophages

• Play a big role

in medicine and widely

are used when

treatment of purulent

diseases,

caused by

staphylococci, etc.

• Used in gene

engineering as

vectors carrying

DNA sections

Viroids

Viroids– pathogens of plant diseases, which consist of a short fragment of circular, single-stranded RNA, not covered with a protein shell characteristic of viruses.

The first viroid identified was a potato tuber viroid

Prions

– “infectious proteins” that do not contain nucleic acids, causing severe diseases of the central nervous system in humans and animals.

Mad cow disease

Prions

A prion protein, which has an abnormal three-dimensional structure, is capable of directly catalyzing the structural transformation of a normal cellular protein homologous to it into a similar one (prion)

β-sheets

α-helix

Prions form insoluble deposits in brain tissue

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Presentation on the topic: Non-cellular life forms

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Viruses have such a simple structure that they are often not considered alive at all. Each viral particle consists of a small amount of genetic material (DNA or RNA) enclosed in a protein shell (capsid). Some viruses contain carbohydrates and fats. Unlike all other organisms, viruses do not have a cellular structure. The fully formed infectious particle is called a virion. Left: tobacco mosaic virus (photo taken with an electron microscope with a magnification of one hundred thousand times). Right: diagram of the structure of the virus; The red strand of RNA is surrounded by protein molecules.

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The reproduction of viruses is fundamentally different from the reproduction of other organisms. It occurs only inside the host cell and includes three stages: 1. The viral nucleic acid multiplies by replication. 2. Capsid proteins are synthesized. 3. Virion assembly occurs (viral particles are formed). Viruses reproduce only inside a living cell, using it to synthesize their nucleic acid and their proteins. Once inside the cell, the virus loses its protein shell, its nucleic acid is released and becomes a matrix for the synthesis of the virus shell protein from the host cells; in this case, the host DNA is inactivated. Viruses are transmitted from cell to cell as inert creatures.

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Characteristics of viruses 1. The chemical composition is represented only by organic substances, and such important inorganic components as water and mineral salts are absent. 2. Viruses do not produce energy and do not consume food. 3. Viruses do not grow and do not metabolize.

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The significance of viruses Viruses are the causative agents of many dangerous diseases of humans, animals and plants. They are transmitted through direct physical contact, airborne droplets, sexual contact and other means. Viruses can also be transmitted by other organisms (vectors): for example, the rabies virus is carried by a dog or a bat. More than ten groups of viruses are pathogenic for humans. Among them there are both DNA viruses (smallpox virus, herpes group, adenoviruses (diseases of the respiratory tract and eyes), papovaviruses (warts), hepadnaviruses (hepatitis B)), and RNA viruses (picornaviruses (hepatitis A, polio, acute respiratory infections) , myxoviruses (influenza, measles, mumps), arboviruses (encephalitis, yellow fever)). Viral diseases also include the human immunodeficiency virus, which causes AIDS, discovered in 1981.

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Methods of transmission of viral diseases Droplet infection is the most common way of spreading respiratory diseases. Coughing and sneezing release millions of tiny droplets of fluid (mucus and saliva) into the air. These droplets, along with the live viruses contained in them, can be inhaled by other people, especially in crowded places that are also poorly ventilated. Standard hygiene practices to protect against droplet infection include proper use of handkerchiefs and ventilation of rooms. Some microorganisms, such as the smallpox virus, are very resistant to desiccation and survive in dust containing dried droplets. Even when talking, microscopic sprays of saliva fly out of the mouth, so this kind of infection is very difficult to prevent, especially if the microorganism is very virulent (infectious). Contagious transmission (through direct physical contact). Relatively few diseases are transmitted through direct physical contact with sick people or animals. This primarily includes sexually transmitted (ie, sexually transmitted) diseases such as AIDS. Contagious viral diseases include common warts (papillomavirus) and herpes simplex - “fever” on the lips. A carrier is any living organism that spreads an infection. It receives infection from an organism called the reservoir or carrier. The rabies virus persists and is transmitted by the same animal, such as a dog or a bat. In these cases, the carrier acts as a second host in whose body the pathogenic microorganism can multiply. Insects can carry pathogens on the external surfaces of the body.

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Viruses are non-cellular life forms

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Viruses (lat. virus - poison) are non-cellular forms of life, that is, they do not have a cellular structure. They represent a transitional form between inanimate and living matter.

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Structure

Viruses are composed of nucleic acid and a protein shell and resemble a particle rather than a cell. Since viruses always contain one type of nucleic acid - DNA or RNA.

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Scheme of the structure of the virus (a) and bacteriophage (b); 1-nucleic acid; 2 - protein shell; 3 - hollow rod; 4 - basal plate; 5 - processes (threads).

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The virus capsid is, as a rule, either a regular polyhedron (dodecahedron or icosahedron) or a spiral-shaped shell.

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Origin of viruses (hypotheses)

Viruses are the result of an extreme manifestation of the regressive evolution of bacteria or other single-celled organisms. viruses are descendants of ancient, precellular life forms - protobionts, which preceded the appearance of cellular life forms, with which biological evolution began. Viruses originate from genetic elements of cells that have become autonomous.

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Reproduction of viruses

The reproduction of viruses is different from the reproduction of other organisms. They reproduce only inside a living cell, using it to synthesize their nucleic acid and their proteins. Once inside the cell, the virus loses its protein shell, its nucleic acid is released and becomes a matrix for the synthesis of the virus shell protein from the host cells.

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Diseases caused by viruses

The tobacco mosaic virus, which has a rod-shaped form and is a hollow cylinder, has been well studied. The wall of the cylinder is formed by protein molecules, and in its cavity there is an RNA helix. The protein shell protects the nucleic acid from unfavorable environmental conditions, and also prevents cell enzymes from penetrating the RNA and breaking it down.

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bird flu virus swine flu virus

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AIDS - acquired immunodeficiency syndrome is an epidemic disease that primarily affects the human immune system, which protects it from various pathogens.

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The causative agent of AIDS is the human immunodeficiency virus (HIV). The HIV genome consists of two identical RNA molecules consisting of approximately 10 thousand base pairs. Moreover, HIV isolated from various AIDS patients differs from each other in the number of bases (from 80 to 1,000).

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The role of viruses in the biosphere

The waters of the world's oceans contain a colossal amount of bacteriophages (about 250 million particles per milliliter of water). The ocean is home to hundreds of thousands of species (strains) of viruses, the vast majority of which have not been described, much less studied. Viruses play an important role in regulating the populations of some species of living organisms

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From the history

The first was discovered in 1901 viral disease human - yellow fever. This discovery was made by the American military surgeon W. Reed and his colleagues. In 1911, Francis Rous proved the viral nature of cancer - Rous sarcoma (only in 1966, 55 years later, he was awarded the Nobel Prize in Physiology or Medicine for this discovery). In 2002, the first synthetic virus (poliomyelitis virus) was created at New York University.

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Thank you for your attention!

Structure Viruses consist of nucleic acid and a protein shell and resemble a particle rather than a cell. Since viruses always contain one type of nucleic acid, DNA or RNA. Viruses are composed of nucleic acid and a protein shell and resemble a particle rather than a cell. Since viruses always contain one type of nucleic acid, DNA or RNA.

Origin of viruses (hypotheses) Viruses are the result of an extreme manifestation of the regressive evolution of bacteria or other single-celled organisms. Viruses are the result of an extreme manifestation of the regressive evolution of bacteria or other single-celled organisms. viruses are descendants of ancient, precellular life forms of protobionts that preceded the appearance of cellular life forms, from which biological evolution began. viruses are descendants of ancient, precellular life forms of protobionts that preceded the appearance of cellular life forms, from which biological evolution began. Viruses originate from genetic elements of cells that have become autonomous. Viruses originate from genetic elements of cells that have become autonomous.

Reproduction of viruses Reproduction of viruses differs from the reproduction of other organisms. They reproduce only inside a living cell, using it to synthesize their nucleic acid and their proteins. Once inside the cell, the virus loses its protein shell, its nucleic acid is released and becomes a matrix for the synthesis of the virus shell protein from the host cells. The reproduction of viruses is different from the reproduction of other organisms. They reproduce only inside a living cell, using it to synthesize their nucleic acid and their proteins. Once inside the cell, the virus loses its protein shell, its nucleic acid is released and becomes a matrix for the synthesis of the virus shell protein from the host cells. protein synthesis protein synthesis

Diseases caused by viruses The tobacco mosaic virus, which has a rod-shaped shape and is a hollow cylinder, has been well studied. The wall of the cylinder is formed by protein molecules, and in its cavity there is an RNA helix. The protein shell protects the nucleic acid from unfavorable environmental conditions, and also prevents cell enzymes from penetrating the RNA and breaking it down. The tobacco mosaic virus, which has a rod-shaped form and is a hollow cylinder, has been well studied. The wall of the cylinder is formed by protein molecules, and in its cavity there is an RNA helix. The protein shell protects the nucleic acid from unfavorable environmental conditions, and also prevents cell enzymes from penetrating the RNA and breaking it down.

AIDS AIDS acquired immunodeficiency syndrome is an epidemic disease that primarily affects the human immune system, which protects it from various pathogens. AIDS acquired immunodeficiency syndrome is an epidemic disease that primarily affects the human immune system, which protects it from various pathogens.

HIV The causative agent of AIDS is the human immunodeficiency virus (HIV). The HIV genome consists of two identical RNA molecules consisting of approximately 10 thousand base pairs. Moreover, HIV isolated from various AIDS patients differs from each other in the number of bases (from 80 to 1,000). The causative agent of AIDS is the human immunodeficiency virus (HIV). The HIV genome consists of two identical RNA molecules consisting of approximately 10 thousand base pairs. Moreover, HIV isolated from various AIDS patients differs from each other in the number of bases (from 80 to 1,000).

The role of viruses in the biosphere The waters of the world's oceans contain a colossal amount of bacteriophages (about 250 million particles per milliliter of water). The ocean is home to hundreds of thousands of species (strains) of viruses, the vast majority of which have not been described, much less studied. The waters of the world's oceans contain a colossal amount of bacteriophages (about 250 million particles per milliliter of water). The ocean is home to hundreds of thousands of species (strains) of viruses, the vast majority of which have not been described, much less studied. Viruses play an important role in regulating the population size of some species of living organisms Viruses play an important role in regulating the population size of some species of living organisms

From history In 1901, the first viral human disease, yellow fever, was discovered. This discovery was made by the American military surgeon W. Reed and his colleagues. In 1901, the first human viral disease, yellow fever, was discovered. This discovery was made by the American military surgeon W. Reed and his colleagues. 1901 yellow fever and medicine). In 1911, Francis Rous proved the viral nature of cancer, Rous sarcoma (only in 1966, 55 years later, he was awarded the Nobel Prize in Physiology or Medicine for this discovery). Nobel Prize in Physiology or Medicine In 2002, the first synthetic virus (poliomyelitis virus) was created at New York University. In 2002, the first synthetic virus (poliomyelitis virus) was created at New York University.2002 New York University polio virus2002 New York University polio virus