General steps in virus replication
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Viruses replicate inside host cells by commandeering the cell's machinery. The replication cycle involves 1) attachment to receptors on the host cell, 2) penetration of the cell, 3) uncoating of the viral genome, 4) transcription of mRNA from the viral DNA or RNA, 5) translation of viral proteins using the host cell's ribosomes, 6) replication of the viral genome, 7) assembly of new virus particles, and 8) release of progeny viruses through cell lysis or budding, resulting in hundreds of new virus particles.
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Baltimore classification virus
This document discusses virus classification systems. It provides an overview of the Baltimore classification system, which categorizes viruses based on their method of mRNA production. Group I viruses contain double-stranded DNA and produce mRNA through transcription. Group II viruses have single-stranded DNA and produce a double-stranded DNA intermediate before transcription. Group III viruses use double-stranded RNA, with one strand serving as the mRNA template. Group IV viruses contain single-stranded RNA with positive polarity that directly serves as mRNA.
Viral replication
Viral replication occurs in six sequential phases: (1) attachment to host cell receptors, (2) penetration via endocytosis or membrane fusion, (3) uncoating of the viral capsid and release of genetic material, (4) biosynthesis of viral mRNA, proteins, and new genomes using host cell machinery, (5) assembly of new virus particles, and (6) release through cell lysis or budding. The host cell provides energy and materials for the virus to replicate its proteins and nucleic acids.
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Classification of virus
The document classifies viruses according to their nucleic acid, capsid, and envelope. Viruses are classified based on whether they contain DNA or RNA, if it is single or double stranded, segmented or not, and positive or negative stranded for RNA viruses. Capsids are classified as icosahedral or helical. Envelopes are naked or enveloped. DNA viruses like herpes, hepatitis, adeno, papilloma, parvo, and pox viruses are usually double stranded, icosahedral, and replicate in the nucleus, with some exceptions. RNA viruses are generally single stranded, enveloped, helical, and replicate in the cytoplasm, though some are double stranded, non-enveloped, or
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Morphology of virus
Viruses are the smallest known infectious agents and lack cellular organization. They contain either DNA or RNA, but not both, and are obligate intracellular parasites that depend on host cell machinery for replication. Viruses infect host cells through attachment to receptors and are then uncoated inside the cell. They hijack the host cell to synthesize viral components and assemble new viral particles that are then released to infect other cells.
Dna Viruses
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The document classifies viruses according to their nucleic acid, capsid, and envelope. Viruses are classified based on whether they contain DNA or RNA, if it is single or double stranded, segmented or not, and positive or negative stranded for RNA viruses. Capsids are classified as icosahedral or helical. Envelopes are naked or enveloped. DNA viruses like herpes, hepatitis, adeno, papilloma, parvo, and pox viruses are usually double stranded, icosahedral, and replicate in the nucleus, with some exceptions. RNA viruses are generally single stranded, enveloped, helical, and replicate in the cytoplasm, though some are double stranded, non-enveloped, or
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Morphology of virus
Viruses are the smallest known infectious agents and lack cellular organization. They contain either DNA or RNA, but not both, and are obligate intracellular parasites that depend on host cell machinery for replication. Viruses infect host cells through attachment to receptors and are then uncoated inside the cell. They hijack the host cell to synthesize viral components and assemble new viral particles that are then released to infect other cells.
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DNA viruses like poxviruses, herpesviruses, and hepatitis B viruses use DNA as their genetic material. Herpesviruses have larger virions and genomes than adenoviruses. They enter cells through fusion with the plasma membrane or endocytosis. During replication, herpesviruses use host enzymes to transcribe early genes that regulate expression of late genes for structural proteins. Virions assemble in the nucleus and acquire an envelope as they bud through the inner nuclear membrane. Viral genomes evolve through spontaneous or induced mutation during replication and by recombining genetic material within or between viruses through breaking and rejoining DNA or RNA.
Properties of viruses
Viruses are small infectious agents that can only replicate inside living host cells. They contain either DNA or RNA and have a variety of shapes, sizes, and structures. Viruses infect all types of organisms from plants and animals to bacteria and archaea. They lack cellular machinery like ribosomes and must hijack host cell mechanisms to produce new viral particles. The replication cycle involves a virus attaching to and entering a host cell, releasing its genetic material, making copies of itself using host cell resources, assembling new viral particles, and exiting to infect new host cells.
Viral taxonomy
The document discusses different systems for classifying viruses. The main systems are the International Committee on Taxonomy of Viruses (ICTV) system and the Baltimore classification system. The ICTV system is based on phenotypic characteristics and defines virus taxonomy, naming conventions, and species. It aims to develop and maintain a universal virus taxonomy. The Baltimore classification system places viruses into one of seven groups based on their nucleic acid and replication strategy.
Chapter 2 classification of virus
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Viral replication
The document discusses the process of viral replication. It begins with an introduction that defines viral replication as the production of all virus components through an assembly process rather than cellular division. It then describes the 7 key steps in viral replication: 1) Attachment, 2) Penetration, 3) Uncoating, 4) Genome replication, 5) Assembly, 6) Maturation, and 7) Release of new virus particles. The document concludes that while the details vary, all viruses follow a similar overall replication process to initiate infection, replicate their genomes, and release new virions.
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The document summarizes the virus replication cycle. It occurs in living host cells and involves several key steps:
1) Attachment and entry of the virus into the host cell.
2) Uncoating of the viral genome from the protein shell.
3) Synthesis of viral mRNA and proteins using the host cell machinery.
4) Replication of the viral genome.
5) Assembly of new viral particles.
6) Release of progeny viruses through cell lysis or budding, which is how enveloped viruses acquire their lipid envelope. The cycle can take 6-40 hours depending on the virus.
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Viruses structure and classification
Viruses consist of genetic material surrounded by a protein coat. They can have DNA or RNA as their genetic material and come in various shapes. The document discusses the structure and classification of viruses. It describes their components, sizes, morphologies like helical and icosahedral shapes. It provides examples of plant, animal, and bacterial viruses. It specifically examines the structure and replication of Cauliflower Mosaic Virus, a plant virus with circular double-stranded DNA genome.
Viral replication
Viral replication is the formation of biological viruses during the infection process in the target host cells. Viruses must first get into the cell before viral replication can occur. From the perspective of the virus, the purpose of viral replication is to allow production and survival of its kind. By generating abundant copies of its genome and packaging these copies into viruses, the virus is able to continue infecting new hosts. Replication between viruses is greatly varied and depends on the type of genes involved in them. Most DNA viruses assemble in the nucleus while most RNA viruses develop solely in cytoplasm
Viral multiplication
Viruses can only replicate inside living cells by going through a viral multiplication cycle. This cycle includes adsorption to the host cell, entry/penetration either through fusion with the plasma membrane or via endosomes, uncoating to release the viral genome, production of viral components in the nucleus or cytoplasm, assembly of new viral particles, and final release through cell lysis or budding through the plasma membrane. The specific steps may vary depending on if the virus has an envelope and what type of genome it contains.
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Classification of viruses
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General properties of viruses
Virology is the study of viruses and their relationship with hosts. Viruses are acellular organisms that can only replicate inside host cells. They have nucleic acid genomes and use host cell machinery to assemble new viral particles. Viruses come in a variety of shapes and sizes, and some have envelopes derived from host cell membranes. They enter host cells, express their genes, replicate their genomes, assemble new viral particles, and exit host cells to infect new targets. Viruses are cultivated using various methods including cell cultures, embryonated eggs, and animal models to study viral replication and pathogenesis.
General Characteristics of Viruses
Obligate intracellular, unable to self-replicate.
Once inside living cells, viruses induce the host cell to synthesize virus particles.
The genome is either DNA or RNA (single or double stranded).
Viruses do not have a system to produce ATP.
Viruses range in size from 25 to 270 nm.
Viral tropism!!
The classification of viruses is based on nucleic acid type, size and shape of virion, and presence or absence of an envelope.
Viral Structure
I . Virion is the entire viral particle.
2. Capsid is the protein coat that encloses the genetic material.
3. Capsomer is the protein subunit that makes up the capsid.
4. Nucleocapsid is composed of the capsid and genetic material.
5. The envelope is the outer coating composed of a phospholipid bilayer, which is composed of viral-encoded glycoproteins and sometimes viral encoded matrix proteins. The envelope is derived from a host cell's membrane.
Some viruses use the plasma membrane, whereas others use endoplasmic reticulum, Golgi, or nuclear membranes. Naked nucleocapsids are viruses with no envelopes.
History of virology
Virology is the study of viruses, which were not well understood until the late 1800s. Early discoveries included Lady Montagu observing inoculation against smallpox in Turkey in the 18th century and Edward Jenner developing the smallpox vaccine using cowpox virus in 1798. In the late 19th century, the development of bacterial filters allowed viruses to be isolated and shown to be smaller than bacteria, causing diseases even when bacteria were removed. By the early 20th century, it was established that viruses could cause diseases in plants, animals, and humans and were distinct from bacteria.
virus multipication strategies.pdf
1. The viral replication cycle consists of 7 stages: attachment, entry, uncoating, transcription/mRNA production, synthesis of viral components, virion assembly, and release.
2. Viruses hijack the host cell's machinery and resources to produce copies of their genetic material and viral proteins. Most steps occur either in the host cell's cytoplasm or nucleus depending on whether the virus contains DNA or RNA.
3. Viruses are classified into 7 categories based on their genome type (DNA or RNA) and replication strategy, such as forming a DNA intermediate or using reverse transcriptase. The classification system provides insight into the diverse mechanisms viruses use to replicate.
virus multipication diagram.pdf
1. The viral replication cycle consists of 7 stages: attachment, entry, uncoating, transcription/mRNA production, synthesis of viral components, virion assembly, and release.
2. Viruses hijack the host cell's machinery and resources to produce copies of their genetic material and viral proteins. Most steps occur either in the host cell's cytoplasm or nucleus depending on whether the virus contains DNA or RNA.
3. Viruses are classified into 7 categories based on their genome type (DNA or RNA) and replication strategy, such as forming a DNA intermediate or using reverse transcriptase. The classification system provides insight into the diverse mechanisms viruses use to replicate.
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Viruses are small infectious agents that can only replicate inside living host cells. They contain either DNA or RNA and have a variety of shapes, sizes, and structures. Viruses infect all types of organisms from plants and animals to bacteria and archaea. They lack cellular machinery like ribosomes and must hijack host cell mechanisms to produce new viral particles. The replication cycle involves a virus attaching to and entering a host cell, releasing its genetic material, making copies of itself using host cell resources, assembling new viral particles, and exiting to infect new host cells.
Viral taxonomy
The document discusses different systems for classifying viruses. The main systems are the International Committee on Taxonomy of Viruses (ICTV) system and the Baltimore classification system. The ICTV system is based on phenotypic characteristics and defines virus taxonomy, naming conventions, and species. It aims to develop and maintain a universal virus taxonomy. The Baltimore classification system places viruses into one of seven groups based on their nucleic acid and replication strategy.
Chapter 2 classification of virus
This document provides an overview of virus classification and the Baltimore classification system. It begins with an introduction to naming conventions for viruses and general approaches to classification. It then describes the Baltimore classification in detail, which divides viruses into 7 classes based on their genome type and replication strategy. The classification focuses on whether the viral nucleic acids are DNA or RNA, and if they are single- or double-stranded. Key viral families are listed as examples for each class.
Viral replication
The document discusses the process of viral replication. It begins with an introduction that defines viral replication as the production of all virus components through an assembly process rather than cellular division. It then describes the 7 key steps in viral replication: 1) Attachment, 2) Penetration, 3) Uncoating, 4) Genome replication, 5) Assembly, 6) Maturation, and 7) Release of new virus particles. The document concludes that while the details vary, all viruses follow a similar overall replication process to initiate infection, replicate their genomes, and release new virions.
Virus structure
This document provides information about virus structure and classification. It begins with the history of virology and defines viruses. It describes the differences between bacteria and viruses, and between DNA and RNA viruses. It outlines the characteristics, structure, replication process, and reaction to physical and chemical agents of viruses. It discusses viral morphology, classification based on shape and presence of an envelope. It also covers bacteriophage structure and important human viruses classified by genome type and associated disease.
Virus multiplication cycle
The document summarizes the virus replication cycle. It occurs in living host cells and involves several key steps:
1) Attachment and entry of the virus into the host cell.
2) Uncoating of the viral genome from the protein shell.
3) Synthesis of viral mRNA and proteins using the host cell machinery.
4) Replication of the viral genome.
5) Assembly of new viral particles.
6) Release of progeny viruses through cell lysis or budding, which is how enveloped viruses acquire their lipid envelope. The cycle can take 6-40 hours depending on the virus.
Protoza
This document provides an overview of protozoa, including their characteristics, morphology, types, reproduction methods, diseases they cause, and drugs used to treat protozoa infections. It defines protozoa as unicellular eukaryotic microorganisms and describes their ectoplasm and endoplasm layers. The document classifies protozoa into four main types - flagellates, ciliates, sarcodina, and sporozoates - and provides examples of diseases caused by pathogenic protozoan species, such as malaria, giardiasis, and toxoplasmosis. It also lists some common antiprotozoal drugs like chloroquine, mefloquine, and metronid
Structure of virus
Viruses lack cellular structures like nuclei, cytoplasm, and cell membranes. They contain nucleic acid surrounded by a protein coat called a capsid. Some viruses have an envelope outside the capsid made of lipids and proteins. Viruses' nucleic acids can be DNA or RNA, single or double stranded. Bacteriophages follow two life cycles: lytic, causing host cell lysis, or lysogenic, where the phage DNA integrates into the host chromosome without killing the cell.
Reoviruses/Reoviridae and Rotavirus
This document discusses the Reoviridae family of viruses. It provides information on Rotavirus, including that it is the most common cause of severe diarrhea in infants and children worldwide, with about 500,000 child deaths annually. Rotavirus has a double-stranded RNA genome and infects the intestinal tract. It spreads easily between young children and causes symptoms like vomiting, diarrhea, and dehydration. While there is no specific treatment, prevention through vaccination is available.
dna and rna Viruses
Viruses are biological agents that reproduce inside host cells. They contain genetic material in the form of DNA or RNA and a protein coat. Viruses come in various shapes and sizes, and there are over 2,000 known virus species that can infect humans and cause diseases like influenza, hepatitis C, and SARS. Viruses have a life cycle where they attach and penetrate a host cell, use the cell to replicate their genetic material and proteins, assemble new virus particles, and are released to infect new cells. Viruses are classified based on their genetic material and structure. Important human virus families include those with RNA genomes like influenza virus and those with DNA genomes like adenovirus.
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This document discusses orthomyxoviruses, which include influenza viruses A, B, and C. It provides details on their structure, including being linear, segmented RNA viruses with negative-sense and enveloped. It also describes the influenza virus life cycle, pathogenesis in humans, clinical symptoms of influenza infection, and methods for prevention and control including inactivated viral vaccines and live attenuated influenza vaccines.
Viruses structure and classification
Viruses consist of genetic material surrounded by a protein coat. They can have DNA or RNA as their genetic material and come in various shapes. The document discusses the structure and classification of viruses. It describes their components, sizes, morphologies like helical and icosahedral shapes. It provides examples of plant, animal, and bacterial viruses. It specifically examines the structure and replication of Cauliflower Mosaic Virus, a plant virus with circular double-stranded DNA genome.
Viral replication
Viral replication is the formation of biological viruses during the infection process in the target host cells. Viruses must first get into the cell before viral replication can occur. From the perspective of the virus, the purpose of viral replication is to allow production and survival of its kind. By generating abundant copies of its genome and packaging these copies into viruses, the virus is able to continue infecting new hosts. Replication between viruses is greatly varied and depends on the type of genes involved in them. Most DNA viruses assemble in the nucleus while most RNA viruses develop solely in cytoplasm
Viral multiplication
Viruses can only replicate inside living cells by going through a viral multiplication cycle. This cycle includes adsorption to the host cell, entry/penetration either through fusion with the plasma membrane or via endosomes, uncoating to release the viral genome, production of viral components in the nucleus or cytoplasm, assembly of new viral particles, and final release through cell lysis or budding through the plasma membrane. The specific steps may vary depending on if the virus has an envelope and what type of genome it contains.
Dna Virus
The document summarizes human DNA viruses, including their structure, replication cycles, and associated diseases. It covers adenoviruses, herpesviruses, papovaviruses, parvoviruses, poxviruses, and hepadnaviruses. Adenoviruses use host cell machinery to replicate their DNA and assemble new virus particles that ultimately cause cell lysis. Herpesviruses and papovaviruses replicate through rolling circle mechanisms. Parvoviruses and hepadnaviruses have unique replication features. Poxviruses are the only DNA viruses that replicate in the cytoplasm.
Classification of viruses
The document provides an overview of virus classification systems. It discusses how viruses were initially named randomly but are now classified systematically. The main classification criteria include the type of nucleic acid (DNA or RNA), number of strands, presence of an envelope, capsid structure, host type, and mode of transmission. Two major classification systems are described - the International Committee on Taxonomy of Viruses (ICTV) system which is based on genomic properties, and the Baltimore classification which is based on mRNA synthesis strategies. The document also discusses classification based on replication properties and site.
Staphylococcus
Staphylococcus are gram positive cocci that commonly colonize human skin and can cause infections. S. aureus is an important human pathogen capable of causing skin infections like impetigo as well as serious infections like pneumonia, meningitis, and toxic shock syndrome. Other pathogenic species include S. epidermidis and S. saprophyticus which can cause opportunistic infections in hospital settings and UTIs respectively. S. aureus is identified through its ability to ferment mannitol and coagulate plasma, while antibiotic resistance has become a major problem in treating staphylococcal infections.
General properties of viruses
Virology is the study of viruses and their relationship with hosts. Viruses are acellular organisms that can only replicate inside host cells. They have nucleic acid genomes and use host cell machinery to assemble new viral particles. Viruses come in a variety of shapes and sizes, and some have envelopes derived from host cell membranes. They enter host cells, express their genes, replicate their genomes, assemble new viral particles, and exit host cells to infect new targets. Viruses are cultivated using various methods including cell cultures, embryonated eggs, and animal models to study viral replication and pathogenesis.
General Characteristics of Viruses
Obligate intracellular, unable to self-replicate.
Once inside living cells, viruses induce the host cell to synthesize virus particles.
The genome is either DNA or RNA (single or double stranded).
Viruses do not have a system to produce ATP.
Viruses range in size from 25 to 270 nm.
Viral tropism!!
The classification of viruses is based on nucleic acid type, size and shape of virion, and presence or absence of an envelope.
Viral Structure
I . Virion is the entire viral particle.
2. Capsid is the protein coat that encloses the genetic material.
3. Capsomer is the protein subunit that makes up the capsid.
4. Nucleocapsid is composed of the capsid and genetic material.
5. The envelope is the outer coating composed of a phospholipid bilayer, which is composed of viral-encoded glycoproteins and sometimes viral encoded matrix proteins. The envelope is derived from a host cell's membrane.
Some viruses use the plasma membrane, whereas others use endoplasmic reticulum, Golgi, or nuclear membranes. Naked nucleocapsids are viruses with no envelopes.
History of virology
Virology is the study of viruses, which were not well understood until the late 1800s. Early discoveries included Lady Montagu observing inoculation against smallpox in Turkey in the 18th century and Edward Jenner developing the smallpox vaccine using cowpox virus in 1798. In the late 19th century, the development of bacterial filters allowed viruses to be isolated and shown to be smaller than bacteria, causing diseases even when bacteria were removed. By the early 20th century, it was established that viruses could cause diseases in plants, animals, and humans and were distinct from bacteria.
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2. Viruses hijack the host cell's machinery and resources to produce copies of their genetic material and viral proteins. Most steps occur either in the host cell's cytoplasm or nucleus depending on whether the virus contains DNA or RNA.
3. Viruses are classified into 7 categories based on their genome type (DNA or RNA) and replication strategy, such as forming a DNA intermediate or using reverse transcriptase. The classification system provides insight into the diverse mechanisms viruses use to replicate.
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Precise presentation on Viral classification and Types of replication in Virus.
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Attachment, Penetration, Uncoating, Multiplication
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Multiplication of Double-Stranded RNA (ds RNA) Viruses
Multiplication of Single-Stranded DNA (ss DNA) Viruses
Multiplication of Double-Stranded DNA (ds DNA) Viruses
Release of new virions
Common viral diseases of Bovines
Virus.ppt
Viruses are parasites that can only replicate inside living host cells. They are made up of genetic material surrounded by a protein coat and have no cell structure of their own. Viruses come in many shapes and sizes but are typically 20-400 nanometers. They infect bacteria, plants, and animals. A virus replicates by entering a host cell, releasing its genetic material, and hijacking the cell's machinery to produce new virus particles that eventually cause the cell to burst and release new viruses. Viruses can have DNA or RNA as their genetic material and replicate through either a lytic or lysogenic cycle.
Lect no.1 a introduction to virology-gen.prop and class
1. Viruses contain either DNA or RNA as their genetic material but not both. This nucleic acid has unique chemical and physical features that distinguish it from human nucleic acid.
2. Viral nucleic acid is enclosed in a protein capsid made of subunits. Some viruses have a surrounding envelope while others do not.
3. Viruses are classified based on their nucleic acid composition, morphology, and whether they have an envelope.
Replication of virus
Viruses rely on host cells to replicate as they cannot do so independently. There are six basic stages of viral replication: 1) attachment to host cell receptors, 2) penetration of the host cell, 3) uncoating of the viral capsid, 4) replication of viral genetic material and proteins, 5) assembly of new viral particles, and 6) release of new virus particles through lysis or budding. The replication process differs between DNA and RNA viruses as well as between viruses with positive-sense and negative-sense genomes, but generally involves the virus taking over host cell machinery to produce more viruses and spread infection.
Plant Virus Infection Cycle and Synthesis
Virus infection involves several steps: virus entry into the host cell, uncoating of the viral genome, targeting of viral genes to host cell machinery, genome replication, assembly of new viral components, and release of progeny virus. Key proteins like movement proteins and coat proteins facilitate various stages of the infection process by transporting the viral genome and protecting it. The virus life cycle is dependent on hijacking host cell processes and resources for its replication and spread to new cells.
Chapter+5,+25,+37 (microbiology) 8th edition
Viruses are genetic elements that cannot replicate independently and cause many diseases. They come in various shapes and sizes and have either DNA or RNA genomes. Viruses infect all types of living organisms including bacteria, archaea, animals, and plants. They replicate inside host cells and can cause cell lysis or establish persistent infections. Important viral models include bacteriophages and retroviruses. Viruses display both lytic and lysogenic life cycles and use a variety of mechanisms to infect hosts and replicate their genomes.
4. life cycle and replication of viruses
Viruses can only replicate inside host cells. There are basic stages required for viral replication: attachment, penetration, uncoating, replication, assembly, maturation, and virion release. Attachment involves the interaction of the virus with a receptor on the host cell surface. Penetration allows the virus to enter the host cell. Uncoating releases the viral genome. Replication produces copies of the viral genome. Assembly packages the new genomes. Maturation modifies viral proteins. Release occurs when new virions exit the host cell through lysis or budding.
Chapter 13 viruse
Viruses contain either DNA or RNA surrounded by a protein coat called a capsid. Some viruses have an outer envelope as well. Viruses infect host cells and use the cell's machinery to replicate their nucleic acid and proteins, eventually causing the cell to burst and release new virus particles. Viruses are classified based on their nucleic acid, replication strategy, and morphology. Common virus families include Herpesviridae, Retroviridae, and Adenoviridae. Viruses can cause disease through lytic infection cycles or establish latent or persistent infections. Some viruses are also associated with cancer development in hosts.
33. an introduction to the viruses
Viruses have capsids made of protein subunits that enclose and protect their nucleic acid. Viruses come in two main shapes - helical or icosahedral - determined by the arrangement of capsomers in the capsid. Some viruses have an envelope in addition to the capsid.
Viral replication involves the virus binding to and entering a host cell, then using the cell's machinery to produce new viral components which are assembled and released to infect new cells. DNA and RNA viruses replicate via different mechanisms using virus-specific enzymes. Animal virus replication is more complex than bacterial viruses due to host cell complexity.
Growing viruses requires appropriate cell cultures or animal hosts that provide an environment where the virus can replicate
вирус.ppt
Viruses are microscopic particles that infect cells and rely on host cells to replicate. They contain genetic material in the form of DNA or RNA and have a protein coat. Viruses infect both eukaryotic and prokaryotic cells and differ from other organisms in their structure, biology, and reproduction. Viruses are classified into groups based on their structure and method of replication, with the Baltimore system categorizing viruses into 7 groups depending on their nucleic acid and method of replication.
Replication of virus.pptx by Manoj mahato
Viral replication is a complex process that involves six main steps: 1) adsorption/attachment where the virus binds to receptors on the host cell, 2) penetration of the virus into the cell, 3) uncoating to release the viral genome, 4) biosynthesis of new viral components, 5) assembly of new virus particles, and 6) release of progeny viruses from the host cell through lysis, degeneration, or budding. Each step involves specific mechanisms depending on whether the virus is enveloped or non-enveloped, DNA or RNA based.
Basic virology (a.3)
Viruses are small infectious agents that can cause diseases in humans. They replicate inside host cells by using the cell's resources. There are three main stages of viral replication: early, central, and final. In the early stage, viruses attach and enter cells. In the central stage, they produce mRNA, proteins, and genomic material. In the final stage, new virus particles assemble and are released. Viruses can mutate, allowing them to evolve and evade host immune responses. They also interact genetically with each other and their hosts. Viruses cause a wide range of human diseases and conditions, from common colds to cancers.
Viral replication by Kainat Ramzan-SlideShare
Virus multiplication are in Following steps: attached, penetration, biosynthesis, maturation, assembly and release and also discribe the life of Bacteriophage by following two life cycle
Present By Kainat Ramzan
Lect 1 introduction to medical virology
Viruses are the smallest infectious agents that can only replicate inside living cells. They contain either DNA or RNA surrounded by a protein coat called a capsid. Some viruses have an outer envelope. Viruses infect cells by binding to receptors on the cell surface and releasing their genetic material inside. The genetic material is then used to hijack the cell's machinery to produce new viral components and assemble new virus particles, which are then released to infect other cells. Viruses are classified based on their structure, genome, proteins, and pathogenicity. Their rapid replication within host cells allows viruses to spread efficiently between individuals.
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the fundementals and the basics of the viral replication cycle.pptx
the fundementals and the basics of the viral replication cycle.pptx
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Lect no.1 a introduction to virology-gen.prop and class
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General steps in virus replication
- 1. Steps in Virus Replication A SEMINAR ON- Presented by- Avijit Pramanik AAH-MA-09-02 B.F.Sc, W.B.U.A.F.S. M.F.Sc, CIFE, Mumbai
- 2. Characteristics of Bacteria and viruses Growth on artificial media Division by binary fission Whether they have both DNA and RNA Whether they have ribosomes Whether they have muramic acid Their sensitivity to antibiotics Bacteria Yes Yes Yes Yes Yes Yes Mycoplasma Yes Yes Yes Yes No Yes Rickettsia No Yes Yes Yes Yes Yes Chlamydia No Yes Yes Yes No Yes Viruses No No No No * No No * The arenavirus family (an RNA virus family) appears to package ribosomes 'accidentally'. The packaged ribosomes appear to play no role in viral protein synthesis.
- 3. Viral Replication: Basic Concepts • Viruses are obligate intracellular parasites • Viruses carry their genome (RNA or DNA) and sometimes functional proteins required for early steps in replication cycle • Viruses depend on host cell machinery to complete replication cycle and must commandeer that machinery to successfully replicate
- 4. • Replication cycle produces - Functional RNA’s and proteins - Genomic RNA or DNA and structural proteins • 100’s-1,000’s new particles produced by each cycle - Referred to as burst size - Many are defective - End of ‘eclipse’ phase • Replication may be cytolytic or non-cytolytic
- 5. 1- Adsorption (Attachment) – Viruses must recognize and bind to specific cellular receptors via particular envelope glycoproteins 2- Penetration There are three different mechanisms Unenveloped viruses enter the cell either by direct translocation across the plasma membrane or by endocytosis
- 6. Steps in Virus Replication (Continued) • Enveloped that have the ability to form syncytia (multinucleated giant cell) enter the cell through fusion of the virion envelope with the cell plasma membrane (e.g. paramyxo and herpes viruses) • The remaining enveloped viruses enter the cell through endocytosis • Endocytosis involves invagination of the cell membrane to form vesicles in the cell cytoplasm. • Infected viruses are then engulfed inside these vesicles.
- 8. • Each vesicle fuses with a lysosome to form lysosomal vesicle. • The viral envelope fuses with the lysosomal membrane and the viral nucleocapsid is expelled into the cytoplasm. 3- Uncoating: • Release of the viral genome from its protective capsid to enable the viral nucleic acid to replicate
- 9. 4- Transcription: Synthesis of m-RNA 5- Translation: The viral m-RNA is translated on cell ribosomes into structural and non- structural proteins. 6- Replication of the viral genome:
- 10. Steps in Viral Replication: Basic Strategies of Transcription and Translation (Fourth and Fifth Steps) (+) RNA Proteins (-) RNA (+) RNA Proteins RNA DNA RNA Proteins DNA RNA Proteins
- 11. 7- Assembly: New virus genomes and proteins are assembled to form new virus particles.
- 12. 8- Release: Enveloped viruses are released by budding Unenveloped viruses are released by rupture of the infected cells.