Creighton Virology

Start Studying!

Terms

undefined, object

copy deck

A virus is made up of ________ & _________: genes (RNA or DNA) & protein-containing coat
One (complete) virus particle: Virion
A virus is an __________ parasite: intracellular
viruses are _____-_____ times smaller then the cells they infect: 100-1000
The smallest virus: parvovirus (20 nm)
The largest virus: poxvirus (300 nm)
The ability of viruses to pass through ______ is used to ID an unknown infectious agent as a bact or virus.: filter
The viral genome can be ______ or ______ stranded: double, single
The viral genome can have 3 basic morphologies: linear, circular, segmented
Retroviruses have a ______ genome: diploid (2 identical copies of the genome - i.e. HIV)
The _____ is the association between nucleic acid & basic proteins either coded by the virus or histones from the host cell: core
The association of core proteins & the genome is required to _______ the viral genome during viral ______ & virion _______: condense, assembly, formation
The protein shell directly surrounding the viral nucleic acid.: Capsid
The complete protein-nucleic acid complex that is the packaged from of the genome in a virus particle: Nucleocapsid
The capsid & nucleocapsid are composed of ___ or at most ___ different kinds of proteins in a crystalline array. Why?: 1, a few. Small genome - rest of genome for intracellular activity
The lipid bilayer & associated glycoproteins that surround many types of virus particles: Envelope
Protein or glycoprotein structure(s) which emanates from the surface of the virus particle: Spikes
Virion structural protein which locates on the cytoplasmic side of the transmem glycoprotein spike. It attracts the completed nucleocapsid for mem fusion.: matrix protein
The structure of the capsid &/or envelope (spikes) has important implications for (3 things): adsorption, hemagglutination (used for ID), recognition of viruses by neutralizing antibodies
The symmetry observed w/ cylindrical viruses (like a slinky): Helical symmetry
The simplest viral symmetry (proteins bind to nucleic acid not a capsule): Helical symmetry
The capsid of a virus composed of many copies of a single kind of protein subunit arranged in a close-packed helix: Helical symmetry
Helical symmetry examples (5): influenza, measles, mumps, rabies, poxviruses (also tobacco mosaic virus - non animal)
Can helical particles form w/o the genome?: No
Symmetry observed w/ spherically shaped viruses. Involves the packing together of many identical subunits. (soccer ball): Icosahedral symmetry (or cubic symmetry)
Morphological subunits that can be seen when capsid is broken (hard to "see" in an intact virus). Surface structures composed of 5-6 protein molecules: Capsomeres
Enveloped virus w/ icosahedral symmetry, the _____ is surrounded by the ________. An example is ______: capsid, envelope, herpes
Enveloped virus w/ helical symmetry, the _____ is coiled w/in the ________. An example is ______: Nucleocapsid, envelope, orthomyxoviruses (influenza)
No clearly identifiable capsid. But several coats around the nucleic acid. An example is _______: Complex virion, poxviruses
Steps to multiply a virus: cell entry, genome replication, viral particle assembly, Egress (escape from host cell)
What definition? The kinds of tissue cells and animal species that a virus can productively infect.: Host Range
What definition? The spectrum of cells which can be productively infected by a given virus.: Tissue tropism
What definition? The capacity of a cell or animal to become infected.: Susceptibility
Cells that become immediately infected are susceptible cells at the ______ ___ __________.: Portal of Entry
What are the cells called that are targeted by the virus and result in clinical disease?: Target cells (ie CNS and HSV)
T or F: Sometimes the target cells are at the portal of entry.: TRUE (ie, influenza, gets into airway and stays there)
What determines host range? (2 things): 1. Cellular Receptors (specificity of attachment); 2. Host intracellular factors
Name the 5 types of Infections:: 1. Productive; 2. Abortive; 3. Latent; 4. Viral transformation; 5. Lytic
What type of infection: The infection of a receptive cell with a virus particle which results in the MULTIPLICATION of infectious viral progeny.: Productive
What type of infection: The infection of a cell which does NOT result in the multiplication of infectious viral progeny.: Abortive
What type of infection: The virus persists in the cell in a noninfectious form.: Latent
What type of infection: The abnormal growth of cells resulting from the continuous expression of one or more viral genes.: Viral Transformation
What type of infection: The infection and subsequent lysis of susceptible cells by a virus.: Lytic
What is the singlemost important thing produced by viruses that gives them the ability to multiply and determines the fate of the infected cell?: The synthesis and function of the VIRAL PROTEINS
The reproductive cycles of ALL viruses exhibit what common feature?: One-step growth curve
T or F: Growth and assay of viruses requires a high multiplicity of infection (MOI): TRUE
What definition: The characteristic morphological changes which occur in the cell due to the infection of a particular virus.: Cytopathic Effect (CPE)
T or F: All viruses produce Cytopathic effect (CPE): False; most do but not all
What is the plaque assay used for?: To determine viral titres; PFU's (show and tell)
What are three methods to use in growth and assay of viruses?: Cytopathic Effect (CPE); Plaque Assay; Molecular techniques (PCR)
What is PCR?: Exponential (2^n) amplification of DNA
What are the 3 steps in PCR?`: 1. Denature DNA template; 2. Anneal primers to the DNA template; 3. Primer extension reaction; (after, you run through this cycle tons of times to get lots of copies of the DNA template)
What are the 3 general stages of initiation of infection?: 1. Adsorption (attachment); 2. Penetration; 3. Uncoating
In the process of adsorption, what are the cellular receptors composed of?: glycoproteins
Viral _________ are examples of antireceptor molecules: spikes
What is adsorption enhanced by?: multiplicities of attachment and receptor proteins
Differences in host range and tissue tropism are due most often to the presence or absence of ___________.: receptors
How do neutralizing antibodies work?: They are specific for an antireceptor on a virus.
T or F: Penetration is energy dependent (not that type of penetration sickos): TRUE
What are the three types of entry?: 1. Translocation; 2. Receptor-mediated endocytosis; 3. fusion
What type of entry: entire virus crosses plasma membrane (non-enveloped): Translocation
What type of entry: results in accumulation of virus particles inside cytoplasmic vesicles (ie influenza this way): Receptor mediated endocytosis
What type of entry: Virion envelope fuses with cellular membrane: Fusion; (ie herpes, measles, HIV)
T or F: The virus can begin replication prior to dismantleling.: False; virus must dismantle first.
What is the process called in the removal of the protective envelope and/or capsid?: Uncoating
The influenza virus is critically dependent on what in order to un-coat and begin replicating?: A low pH. The acidified endosome of receptor-mediated endocytosis releases the nucleocapsid into the cytoplasm.
What is the portion of the cell membrane called that breaks off and surrounds the virus during receptor-mediated endocytosis?: The endosomal vesicle (or just endosome) **It is acidic, which is critical in the release of the nucleocapsid in the influenza virus.
What is the portion of the virus called that is surrounded by the envelope?: The nucleocapsid
What process does the Herpesvirus undergo to enter the cell and undergo de-coating?: Membrane fusion
During membrane fusion, the _________ fuses with the plasma membrane of the host cell, thus releasing the __________ into the cell.: Envelope; Nucleocapsid
What is the KEY event in virus replication?: The synthesis of viral proteins (utilizing the host's protein synthesizing machinery)
Most RNA viruses replicate in the ___________.: cytoplasm
Most DNA viruses replicate in the ___________.: nucleus (except poxviruses)
In order for the virus to replicate, what must it present to the cell?: A viral specific mRNA that the cell can recognize and then translate.
mRNA strands have a ______ polarity.: (positive) +
RNA molecules which are complementary to mRNA have a ______ polarity.: Negative -
The coding DNA strand is always a ________ polarity.: Negative -
What is the process in RNA that removes intervening sequences that do not encode for protein product?: Splicing
What is a long polypeptide chain that is translated from a single transcript with a single ribosome binding site?: Polyprotein
T or F: During encapsidation, self-assembly of component parts occurs in a random fashion: False; it's a stepwise and ordered fashion
During encapsidation, Individual structural subunits or protomeres are preformed into __________ in preparation for final assembly.: Capsomeres
What is the location in the cell where assembly initiates?: The Packaging Site
Where does assembly take place for the herpes virus?: In the Nucleus
Where does assembly take place for the influenza virus?: Cytoplasm
What stages make up the "eclipse (flat line)" state of the one-step growth curve?: Uncoating, replication and assembly, & maturation
What are the 2 ways for release of the virus from a cell?: Cell death--for naked capsid viruses that lack a lysis mechanism (don't need protection of envelope; Budding--acquire their membrane by budding either through the plasma membrane, nuclear membrane (herpes), or golgi or early endosome network (poxvirus)
T or F: The process of viral budding alone will cause cell death.: False; The loss of normal cellular function required for survival is what leads to death.
T or F: Retroviruses can reproduce without cell death.: True, in certain cell types
Which virus(es) are: double-stranded DNA virus that replicates in the nucleus (circular or linear) (3): Herpesvirus, adenovirus, papillomavirus
Which virus(es) are: double-stranded DNA virus that replicates in the cytoplasm?(1): Poxvirus
Which virus(es) are: Single-stranded DNA virus? (1): Parvovirus
Which virus(es) are: Positive-strand RNA virus coding for one genome-sized RNA? (2): Picornaviruses, Hepatitis C
Which virus(es) are: Positive-strand RNA virus coding for one or more subgenomic mRNAs? (4): Coronavirus, Togavirus, Calicivirus, Hepatitis E
Which virus(es) are: Retrovirus (1): HIV
Which virus(es) are: Non-segmented negative-strand RNA virus (3): Paramyxoviruses (RSV, Measles, Mumps), Rhabdovirus, Filovirus
Which virus(es) are: Segmented Negative Strand RNA virus (1): Orthomyxovirus (influenza)
Which virus(es) are: Double-stranded RNA virus? (2): reovirus, rotavirus
Which virus(es) are: Relaxed circular, partially duplexed DNA virus? (1): HBV
What are the five patterns of Viral Pathogenesis?: 1. Acute infection; 2. Latent infection; 3. Chronic Infection; 4. Slow Chronic infection w/out acute infection (ie prions) 5. Transformation (ie Cancer)
Which pattern of viral pathogenesis? Viral infection which is rapidly cleared by host immune response.: Acute infection
Which pattern of viral pathogenesis? Follows acute infection, virus persists in noninfectious form w/ intermittent periods of reactivation & shedding.: Latent infection
T or F: Latent infection viruses (Ie HSV) can cause a productive infection in some cells while simultaneously are latent in other cells: True; (ie epithelial cells & neuronal tissue for HSV)
Which pattern of viral pathogenesis? Follows acute infection, infected cell survives resulting in low level persistent viral production.: Chronic infection
Which pattern of viral pathogenesis? Only one involving prions (no known viruses cause this type of infection).: Slow chronic w/out acute infection
Which pattern of viral pathogenesis? The abnormal growth of cells resulting from the continuous expression of one or more viral genes; cancer.: Transformation
Retroviruses and all major groups of DNA viruses EXCEPT ____________ are associated with the pattern of pathogenesis ____________.: parvoviruses; transformation
What virus? Large, Enveloped icosahedral capsid, Double-stranded linear DNA, Replicates in the nucleus.: Human Herpesviruses
Name the 3 subfamilies of Herpesviradae:: 1. Alphaherpesvirinae; 2. betaherpesvirinae; 3. gammaherpesvirinae
List the herpesvirinae groups in order of most variable host range to most limited host range.: Alpha (most variable), Beta, Gamma(most limited
Where does the alphaherpes establish latency?: Primary sensory ganglia
Where does the betaherpes establish latency?: secretory glands, lymphoreticular cells, kidneys, and other tissues
Where does the gammaherpes establish latency?: Lymphoid tissue
Which has a longer reproductive cycle? Alpha or beta herpes?: Beta
Which herpes readily establishes carrier cultures?: Beta
Which herpes is specific for either B or T Lymphocytes?: Gamma
Herpes uses the host cell DNA-dependent RNA polymerase to synthesize ________.: mRNA
In herpes, What does the last cycle of mRNA transcript encode for?: The viral structural proteins. (goes thru 2 or 3 cycles of transcription first)
Where does Herpes double-stranded DNA replicate?: In the Nucleus
What are the 3 common names of the alpha subfamily herpes?: HSV 1, HSV 2, Varicella-Zoster (VZV)
What are the 2 common names of the gamma subfamily herpes?: Epstein Barr Virus, Kaposi's sarcoma
What is the common name of the beta subfamily of herpes?: cytomegalovirus (CMV)
How is herpes transmitted?: direct contact (saliva, vagina, lesion fluid)
What causes herpes to reactivate?: stress; immune suppression
How does herpes avoid antibodies?: by cell to cell spread (syncytia)
What is required for resolution of herpes?: cell-mediated immunity (limited role for antibodies)
T or F: Herpes has a seasonal incidence: FALSE
T or F: Only select few of the stages of viral replication could be a target for antiviral therapy.: False; theoretically any stage could
Name the antiviral: Guanosine analog, takes advantage of thymidine kinase (TK) and DNA polymerase to inhibit viral replication: Acyclovir
What virus? Non-enveloped icosahedral capsid, Double stranded circular DNA, Replicates in the nucleus: Human papillomavirus (HPV)
T or F: Genital warts and non-genital warts are the same type of HPV: False; they differ
How is HPV transmitted?: contact
What could happen if you just so happen to ACCIDENTALLY aspirate cervico-vaginal secretions infected with HPV?: Laryngeal disease
What is the incubation period for HPV?: 3 months to years
T or F: HPV can be treated with antivirals: FALSE
Which serotypes of cervical cancer are caused by HPV?: 16 and 18
What oral manifestations can HPV have?: oral benign epithelial tumors
What virus? Icosahedral capsid, enveloped, positive single-stranded RNA, Acquire envelope by budding into intracellular vesicles, not at the cell surface: Hepatitis C Virus (HCV)
What is the #1 cause of liver transplantations in the US?: HCV
There are how many people infected w/ HCV in the US?: 4 million (1 in 70-100) Numbers baby.
How is HCV transmitted?: blood (ie needlesticks)
T or F: HCV can be asymptomatic: TRUE
What 3 types of disease can HCV cause?: Acute (15%), Chronic (70%, 20-40% progress to cirrhosis & liver failure), Rapid cirrhosis (15%) (5% develop cancer after 30 years)
T or F: HCV can be managed by antivirals.: FALSE
T or F: There is no vaccine for HCV.: TRUE
What can you use to treat HCV?: Interferon alpha, and ribavarin
What virus? Helical, single strand positive RNA, enveloped: Coronavirus
What virus is associated with SARS?: coronavirus
T or F: SARS virus is localized to upper respiratory tract: TRUE
What is SARS-CoV?: a coronavirus
How are coronaviruses (SARS) spread?: Aerosols and large droplets
What is the first symptom of SARS?: High fever (> 100.4 F), then headaches, discomfort, body aches
As a symptom of SARS, about 10-20% of people also have ________.: diarrhea cha cha cha
T or F: Most SARS patients normally develop pneumonia.: TRUE
T or F: There are antivirals that effectively treat SARS.: FALSE
What Virus? Positive single-stranded RNA (diploid), Icosahedral capsid, Enveloped, Reverse Transcriptase (RT): RNA-dependent DNA polymerase: HIV
Regarding HIV infection, what is the purpose of the GENOMIC RNA?: To serve as a template for the synthesis of viral DNA
What primary infection results in mononucleosis-like syndrome?: HIV
What effect does the initial immune response have on HIV infection?: Restricts viral infection but contributes to pathogenesis
What is the terminal stage of an HIV infection?: AIDS
How is HIV transmitted? (think magic johnson and Paul): Sex and blood

Start Studying!

Deck Info

Number of cards 160