Intro to Viruses (PP) Flashcards by Medically Makk

Viral Replication

Antibody receptor antagonist

powerpoint

Step 1: Recognition of target cell

Step 2: Attachment

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Step 1 of Viral replication

Recognition of target cell

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Step 2 of Viral replication

Attachment

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Step 3 of Viral replication

Penetration

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Step 4 of Viral replication

Uncoating
antivirals = amantadine, arildone, rimantadine, tromantadine

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Step 5 of Viral replication

Transcription
antivirals: interferon, antisense oligomers

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Step 6 of Viral replication

Protein synthesis (translation), antivirals: interferon

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Step 7 of Viral replication

Replication

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Step 8 of Viral replication

Assembly, antirvirals: protease inhibitors

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Step 9 of Viral replication

Lysis and release or budding and release

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VIRUSES IN HUMAN INFECTIONS AND DISEASES

Viruses are obligate ____ ___-

intracellular parasites

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VIRUSES IN HUMAN INFECTIONS AND DISEASES

Viruses ____ (can/cannot) make energy or proteins independently of a host cell

can not, they need the host cell

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VIRUSES IN HUMAN INFECTIONS AND DISEASES

All DNA viruses are double-stranded expect for ….

except for parvoviruses, which have ssDNA

ss= single stranded

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VIRUSES IN HUMAN INFECTIONS AND DISEASES

All RNA viruses are single-stranded except for ____ ___

except for dsRNA reoviruses

double stranded RNA reoviruses

respiratory entreric orphans

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DNA VIRUSES

name the 4 DNA viruses

HSV, EBV, HBV, HPV

Herpes, Epstein-Barr, Hepatitis B, and Human Papillomavirus

Triple HE

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RNA VIRUSES

Name the 3 rna viruses?

influenza, Hepatitis C, and HIV 1&2

DOUBLE HI

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VIRAL STRUCTURES

what type of capsid can antibodies recognize well?

naked capsid

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VIRAL STRUCTURES

3 things in the enveloped virus

lipid bilayer, structural protein, glycoprotein

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VIRAL STRUCTURES

what does enveloped viruses have?

contains lots of glycoproteins, the participate in cell mediated response and antibody response

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Herpesviruses are

enveloped double stranded dna

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influenza is a

enveloped single stranded rna virus with segmented genome, orthomyxoviruses

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VIRAL REPLICATION

Viruses are limited to __ (2 things )

a particular host (host range) or cell type (cellular tropism)

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VIRAL REPLICATION

Many viruses are strictly

human in origin

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VIRAL REPLICATION

Most DNA viruses multiply within and are budded off

the nucleus (except Poxviruses)

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# VIRAL REPLICATION Most RNA viruses multiply in and are released from the

cytoplasm (except Orthomyxoviruses and Retroviruses)

# VIRAL pathways nucleotide biosynthesis and mutation drug?

ribavirin | treats hcv

thymidine kinase (drug activation) , what are the drugs

acyclovir, penciclovir | treats herpes

neuraminidase, drug names?

zanamivir, oseltamivir | treats influenza A/B

# PROPERTIES OF DNA VIRUSES DNA is not ...

transient or labile. | hearty adn sticks around longer

# PROPERTIES OF DNA VIRUSES The larger DNA viruses encode means to

promote efficient replication of their genome. | herpes is a large virus

# PROPERTIES OF DNA VIRUSES DNA polymerases require a primer to

replicate the viral genome.

# PROPERTIES OF DNA VIRUSES Viral gene transcription is temporally regulated. Early genes encodes ...

DNA-binding proteins and enzymes.

# PROPERTIES OF DNA VIRUSES Viral gene transcription is temporally regulated.Late genes encode

structural and other proteins.

# PROPERTIES OF DNA VIRUSES Viral DNA resembles host DNA for ...

transcription and replication

# PROPERTIES OF DNA VIRUSES DNA genomes

reside in the nucleus

# what does it do? Papillomavirus

: stimulates cell growth and DNA synthesis.

Hepadnavirus

: stimulates cell growth, cell makes RNA intermediate, encodes a reverse transcriptase. | dna reverse, the dna tha changed to a rna

Herpesvirus

: stimulates cell growth, encodes its own polymerase and enzymes to provide deoxyribonucleotides for DNA synthesis, establishes latent infection in host.

Poxvirus

: encodes its own polymerases and enzymes to provide deoxyribonucleotides for DNA synthesis, replication machinery, and transcription machinery in the cytoplasm.

# PROPERTIES OF RNA VIRUSES RNA is

labile and transient. | degraded easily

# PROPERTIES OF RNA VIRUSES Most RNA viruses replicate

replicate in the cytoplasm.

# PROPERTIES OF RNA VIRUSES Cells cannot replicate RNA. RNA viruses must encode an

RNA-dependent RNA polymerase.

# PROPERTIES OF RNA VIRUSES The genome structure determines the mechanism of (2 things)

transcription and replication.

# PROPERTIES OF RNA VIRUSES RNA viruses are prone to

mutation | mutate quicker

# PROPERTIES OF RNA VIRUSES RNA viruses, except for (+) RNA genome, must carry

polymerases ## Footnote our mrna is +sense, some viruses that are + sense use us.

# PROPERTIES OF RNA VIRUSES all (−) RNA viruses are

enveloped

# rna examples (+) RNA genome resembles mRNA and is translated into a ________ , which is proteolyzed. A (−) RNA template is used for _______.

polyprotein, replication ## Footnote Picornaviruses, Hepeviruses, Astroviruses, Togaviruses, Flaviviruses, Caliciviruses, and Coronaviruses

# rna examples (−) RNA genome is a template for individual mRNAs, but the full-length (+) RNA template is required for ....

replication ## Footnote Orthomyxoviruses, Paramyxoviruses, Rhabdoviruses, Filoviruses, and Bunyaviruses

# rna examples Orthomyxoviruses replicate and transcribe in the nucleus, and each segment of the genome encodes .....

one mRNA and is a template.

# rna examples (+) Retrovirus RNA genome is converted into DNA, which is integrated into the host chromatin and ____- ## Footnote Retroviruses

transcribed as a cellular gene.

# VIRAL DISEASE Course of viral disease: invasion at portal of entry and primary infection; some viruses replicate locally, others enter the circulation and infect other

tissues

# VIRAL DISEASE Chronic infections

virus detectable in tissue samples, multiplying at a slow rate; symptoms mild or absent

# VIRAL DISEASE In a lytic cycle, the virus introduces its genome into a host cell and initiates replication by ...

hijacking the host's cellular machinery to make new copies of the virus.

# VIRAL DISEASE Latent infections

after a lytic cycle, virus enters a dormant phase; generally, not detectable; can reactivate and result in recurrent infections

# VIRAL DISEASE lysis definition

the disintegration of a cell by rupture of the cell wall or membrane.

# VIRAL DISEASE Oncogenic DNA viruses

Epstein–Barr virus (EBV), hepatitis B virus (HBV), human papillomavirus (HPV),human herpesvirus-8 (HHV-8), and Merkel cell polyomavirus (MCPyV

# VIRAL DISEASE Oncogenic RNA viruses

: hepatitis C virus (HCV) and human T-cell lymphotropic virus-1 (HTLV-1).

# VIRAL GENETICS Mutations spontaneously and readily occur in viral genomes, creating new virus strains with

properties different from the parental or wildtype virus

# VIRAL GENETICS Mutations in essential genes can...

inactivate the virus (lethal mutations)

# VIRAL GENETICS Mutations in other genes may produce antiviral drug resistance or alter the

antigenicity or pathogenicity ofthe virus

# VIRAL GENETICS Viral polymerases are error prone and generate many

mutations during replication of the genome

# VIRAL GENETICS RNA viruses lack a genetic

error-checking mechanism

# VIRAL GENETICS New virus strains can also arise by genetic interactions between viruses or between

the virus and the cell

# VIRAL GENETICS Viruses with segmented genomes (e.g., influenza viruses and reoviruses) form hybrid strains on infection of one cell with more than one virus strain, that is called?

reassortment

# VIRAL VECTORS FOR THERAPY Viruses that are being developed as vectors include

retroviruses, adenoviruses, HSV, an adeno-associated virus (parvovirus), poxviruses (e.g., vaccinia and canarypox) and even some togaviruses

antigenic shift causes changes in rna strands. what virus?

influenza

cytopathic, meaning that

cells are killed during the course of infection,

budding,

part of the host cell membrane becomes part of the virus.