MBIO 4310 - Final Exam Review Questions
The invention of microscopes that allow visualization of viruses provided a major boost to the study of viruses. Which technique allows the construction of 3-dimensional reconstructions of a virus? 1. Cryo-electron microscopy 2. Cryo-electron tomography 3. Light microscopy 4. Scanning electron microscopy 5. Transmission electron microscopy
2. Cryo-electron tomography
If the HIV-1 capsid is destabilized on its entry into the cytoplasm by the action of host TRIM5cyp and the activation of host protein MX2 before reverse transcription takes place, what is the outcome of the viral infection for that virion? A. Abortive infection B. Hypermutation of the genome C. Latent infection D. Lytic infection E. Silencing on nuclear entry
A. Abortive infection
Which of the following genomes is NOT found among known viruses? A. Ambisense DNA B. Ambisense RNA C. Double-stranded DNA D. Double-stranded RNA E. Single-stranded DNA F. Single-stranded RNA
A. Ambisense DNA
Viruses have mechanisms to interfere with host intrinsic, innate, and adaptive responses to cellular infection. However, some viruses can highjack a host molecule, cell, or process to their advantage. For example, Poliovirus and several flaviviruses use this to facilitate construction of double membrane vesicles for replication. Which of the following is the host molecule, cell, or process? A. APOBEC3 B. Autophagy C. Interferon-α/β D. Natural killer cells E. Helper T cells
B. Autophagy
At which point(s) in the illustration of an adenovirus (Mastadenovirus) infection would the infected individual transmit the virus to another individual? A. A, acquisition of the virus B. B, acute infection of the upper respiratory tract (URT) C. C, persistent infection of the gastrointestinal tract (GI) D. D, latent infection of the lymph node E. E, infection in the liver
B. B, acute infection of the upper respiratory tract (URT) C. C, persistent infection of the gastrointestinal tract (GI)
The most common type of endocytic entry used by viruses to enter cells involves A. Caveolin-mediated endocytosis B. Clathrin-mediated endocytosis C. Clathrin- and caveolin-independent endocytosis D. Lipid raft-mediated endocytosis E. Macropinocytosis
B. Clathrin-mediated endocytosis
Which of the following cells, molecules, or processes is specific to the host innate response to viruses? A. Antibodies B. Complement C. Cytokines D. Cytotoxic T cells (CD8 cells) E. Helper T cells (CD4 cells)
B. Complement
Species of Enterovirus cause many different types of infection. Which of the Enterovirus species is the major cause of the infection shown in the image that is common in young children, especially in daycare centers? A. Aphthovirus B. Coxsackievirus A C. Hepatovirus D. Poliovirus E. Rhinovirus
B. Coxsackievirus A
As a research scientist, you have been given the task of determining the three-dimensional shape of the virions and its components. Cytopathic effect caused by the replicating viruses has been observed in cell culture. Intact virions have been observed by electron microscopy to be present in the cytoplasm. Which microscopic method would be the best approach to complete your task? A. Confocal laser scanning microscopy B. Cyro-electron microscopy with computed tomography C. Fluorescence microscopy D. Light microscopy E. Scanning electron microscopy F. Transmission electron microscopy
B. Cyro-electron microscopy with computed tomography
Among the Parvoviridae, which genus is used as a vector for gene therapy? A. Bocaparvovirus B. Dependoparvovirus C. Erythroparvovirus D. Iteravirus E. Protoparvovirus
B. Dependoparvovirus
Which of the following is the correct term to describe the situation in which a similar number of cases of a particular viral infection occur within a population from year to year? A. Sporadic B. Endemic C. Outbreak D. Epidemic E. Pandemic
B. Endemic
Because of the continual variation in the strains of Alphainfluenzavirus and Betainfluenzavirus that make it difficult to prepare a vaccine with high efficacy (greater than 60% effective at neutralizing the CURRENTLY circulating strains of influenzaviruses, Scientists are attempting to produce a universal influenza vaccine. While several proteins have been proposed as targets for production of such vaccine, which is the main target for most of the current universal vaccine trials? A. Hemagglutinin head domain B. Hemagglutinin stalk domain C. M1 matrix protein D. M2 envelope protein E. Neuraminidase head domain
B. Hemagglutinin stalk domain
Which of the following viruses replicates in a nuclear viral factory (viroplasm)? A. Chikungunya virus (Togaviridae) B. Herpes simplex virus 1 (Herpesviridae) C. Dengue virus (Flaviviridae) D. Poliovirus (Picornaviridae) E. Vaccina virus (Poxviridae)
B. Herpes simplex virus 1 (Herpesviridae)
Lytic bacteriophages encode at least one protein that is necessary for lysis of the bacterial cell to allow release of the virions. Which of the proteins associated with bacterial cell lysis is known to function in disrupting the inner cytoplasmic membrane for the Teseptimavirus T7 virus? A. Endolysin B. Holin C. Lysozyme p5 D. Spanin 1/2
B. Holin
Both host and viral factors play a role in the ability of a virus to cause disease. Which factor is related to the host rather than the virus? A. Enhanced replication B. Immunopathogenesis C. Infectious dose D. Oncogenesis E. Tissue tropism
B. Immunopathogenesis
In which of the Flavivirus cycles of infection are humans a dead-end host? A. Dengue virus B. Powassan virus C. Yellow fever virus D. Zika virus
B. Powassan virus
Which numbered segments of the genome of Lentivirus HIV-1, contain genes common to all retroviruses? More than one answer expected; extra credit. A. Segment 1, LTR B. Segment 2, gag C. Segment 3, pro D. Segment 4, pol E. Segment 5, tat F. Segment 6, vpu G. Segment 7, env H. Segment 8, rev
B. Segment 2, gag C. Segment 3, pro D. Segment 4, pol G. Segment 7, env
In the problem of the ongoing development of circulating vaccine-derived poliovirus (cVDPV) strains, which strain of the virus, declared eradicated from the world in 2015, has been responsible for most of the cases of acute flaccid paralysis? A. cVDPV type 1 B. cVDPV type 2 C. cVDPV type 3 D. Undefined serotype of cVDPV
B. cVDPV type 2
Which of the following terms classifies a group of viruses by their tissue tropism? A. Arboviruses B. Bacteriophages C. Enteroviruses D. Hepatitis viruses E. Parvoviruses
C. Enteroviruses
Which genus of the Parvoviridae causes the most serious disease in humans? A. Bocaparvovirus B. Dependoparvovirus C. Erythroparvovirus D. Iteravirus E. Protoparvovirus
C. Erythroparvovirus
The electronmicrograph shows different types of structures observed in the blood of an individual infected with Orthohepadnavirus (Hepatitis B virus). What protein composes the structures labeled subviral particles? A. HBcAg B. HBeAg C. HBsAg D. P protein E. HBx protein
C. HBsAg
Several different viruses have entered the Western Hemisphere (North America, South America, Central America, and the Caribbean) in the past two decades. Which of the following viruses is locally transmitted within almost every state in the continental United States every year? A. Chikungunya virus B. Dengue virus C. West Nile virus D. Zika virus
C. West Nile virus
Which type of viruses always replicate in the cytoplasm (one of the few certainties in virology)? A. dsDNA viruses that do not use reverse transcriptase B. ssDNA viruses C. (−) ssRNA viruses D. (+) ssRNA viruses that do not use reverse transcriptase
D. (+) ssRNA viruses that do not use reverse transcriptase
Which of the member of the Reoviridae causes the most death in humans? A. Coltivirus B. Orbivirus C. Orthoreovirus D. Rotavirus E. Seadornavirus
D. Rotavirus
Within the family Reoviridae, which of the viruses below causes serious gastrointestinal infection, especially in children? A. Coltivirus B. Norovirus C. Orbivirus D. Rotavirus E. Seadornavirus
D. Rotavirus
Most viruses acquire their envelope membranes by budding through cellular membranes. Which virus acquires such an envelope by budding through the endoplasmic reticulum and then discards it before being exocytosed? A. Coronaviruses B. Herpesviruses C. Influenzaviruses D. Retroviruses E. Rotaviruses
E. Rotaviruses
Which one of the following replication schemes is used by hepadnaviruses of Baltimore Class VII? A. (−) ssRNA to (+) ssRNA to (−) ssRNA B. (+) ssRNA to (−) ssRNA to (+) ssRNA C. (+) ssDNA and (−) ssDNA to dsDNA to (−) ssDNA and (+) ssDNA 5% D. (+) ssRNA to (−) ssDNA to dsDNA to (+) ssRNA E. dsDNA to dsDNA F. dsDNA to (+) RNA to (−) ssDNA to dsDNA G. dsRNA to (+) ssRNA to dsRNA
F. dsDNA to (+) RNA to (−) ssDNA to dsDNA
Four different viruses were visualized by electron microscopy - (1) a naked virus with a rod-shaped nucleocapsid exhibiting helical symmetry, (2) a naked virus with an icosahedral nucleocapsid, (3) an enveloped virus with an icosahedral nucleocapsid, and (4) an enveloped virus with a helical nucleocapsid. Which of the virus(es) would you expect to be susceptible to inactivation by soap or alcohol? A. Virus 1 only (naked rod-shaped helical virus) B. Virus 2 only (naked icosahedral virus) C. Virus 3 only (enveloped icosahedral virus) D. Virus 4 only (enveloped helical virus) E. Both of the helical viruses (1 and 4) F. Both of the icosahedral viruses (2 and 3) G. Both of the naked capsid viruses (1 and 2) H. Both of the enveloped viruses (3 and 4)
H. Both of the enveloped viruses (3 and 4)
Match the disease with the corresponding virus that causes that disease: Infectious mononucleosis Cervical cancer Gastroenteritits (vomiting and diarrhea) Aseptic meningitis A. Norovirus B. Human papillomavirus 16 C. Rhadinovirus (Kaposi's sarcoma-associated herpesvirus) D. Lymphocryptovirus (Epstein-Barr virus) E. Enterovirus echovirus F. Chikungunya virus G. Merkel cell polyoma virus H. Coltivirus
Infectious mononucleosis - D. Lymphocryptovirus (Epstein-Barr virus) Cervical cancer - B. Human papillomavirus 16 Gastroenteritits (vomiting and diarrhea) - A. Norovirus Aseptic meningitis - E. Enterovirus echovirus
Match the virus to its description found in the lettered list below. Simplexvirus (HSV1) Dependoparvovirus (AAV) Betapolyomavirus (JC PyV) Alphavirus Chikungunyavirus (CHIKV) A. Enveloped (+) ssRNA virus with an icosahedral capsid B. Enveloped dsDNA virus with a complex capsid C. Enveloped dsDNA virus with an icosahedral capsid D. Naked dsDNA virus with an icosahedral capsid E. Naked dsRNA virus with 3 shells F. Naked ssDNA virus with an icosahedral capsid
Simplexvirus (HSV1) - C. Enveloped dsDNA virus with an icosahedral capsid Dependoparvovirus (AAV) - F. Naked ssDNA virus with an icosahedral capsid Betapolyomavirus (JC PyV) - D. Naked dsDNA virus with an icosahedral capsid Alphavirus Chikungunyavirus (CHIKV) - A. Enveloped (+) ssRNA virus with an icosahedral capsid
Many viruses use RNA secondary structures for different purposes. Which RNA structure provides the Flavivirus genus with an sfRNA that inhibits host RIG-1 antiviral activity? A. 3'-stem-loop structure B> 5'- and 3'-hairpin loops C. 5'-internal ribosome entry site D. Downstream hairpin loop E. Pseudoknot
A. 3'-stem-loop structure
If a virus enters (infects) a nonpermissive cell, the virus will be unable to complete its replicative cycle. What is the term for this outcome? A. Abortive infection B. Latent infection C. Lytic infection D. Persistent infection E. Productive infection
A. Abortive infection
In comparing the replicative cycles of the herpesviruses and poxviruses, which statement is characteristic for poxviruses ONLY? A. An actin propulsion mechanism can be used for exiting virions B. Transcription and translation are under temporal control C. Virions are produced in viral factories (viroplasms) D. Virions gain their envelope in the Golgi complex E. Virions are assembled in the nucleus
A. An actin propulsion mechanism can be used for exiting virions
Influenzavirus B causes local outbreaks and small epidemics in a 2-3 year cycle. Which phenomenon explains why this occurs? A. Antigenic drift B. Antigenic shift C. Complementation D. Development of defective interfering particles E. Template (or strand) switching
A. Antigenic drift
The severe viral disease, foot-and-mouth disease, occurs among farm animals and has a heavy economic impact on meat production. Which of the following genus or species of Picornaviridae is the cause? A. Aphthovirus B. Enterovirus C. Hepatovirus D. Parechovirus E. Poliovirus
A. Aphthovirus
Which of the following virus families with segmented genomes have ambisense segments? More than one answer; extra credit A. Arenaviridae (Mammarenavirus, Lymphocytic choriomeningitis virus) B. Hantaviridae (Orthohantavirus, Sin Nombre virus) C. Orthomyxoviridae (Thogotovirus, Dhori Bourbon virus) D. Nairoviridae (Orthonairovirus, Crimean Congo hemorrhagic fever orthonairovirus) E. Peribunyaviridae (Orthobunyavirus, La Crosse virus) F. Phenuiviridae (Phlebovirus, Heartland phlebovirus)
A. Arenaviridae (Mammarenavirus, Lymphocytic choriomeningitis virus) F. Phenuiviridae (Phlebovirus, Heartland phlebovirus)
Which route of transmission is common between the animal pathogen Orbivirus and the human pathogen Coltivirus? A. Arthropod vector B. Blood transfusion C. Fecal-oral route D. Respiratory route E. Sexual route
A. Arthropod vector
Several families of viruses that belong to the order Bunyavirales and the genera of the Orthomyxoviridae engage in cap-snatching to provide 5' caps for their mRNAs. Which statement correctly describes the location of the cap-snatching by these viruses? A. Bunyavirales in the cytoplasm, Orthomyxoviridae in the nucleus B. Bunyavirales in the nucleus, Orthomyxoviridae in the cytoplasm C. Both Bunyavirales and Orthomyxoviridae the cytoplasm D. Both Bunyavirales and Orthomyxoviridae in the nucleus
A. Bunyavirales in the cytoplasm, Orthomyxoviridae in the nucleus
Many viruses encode multiple types of proteins. Which type of protein is necessary for all viruses that infect vertebrates? A. Capsid proteins B. Envelope proteins C. Proteins to regulate host immune responses D. Reverse transcriptase E. RNA-dependent RNA polymerase
A. Capsid proteins
Two viruses that cause febrile illness with headache and rash invaded the Western Hemisphere, an Alphavirus in 2013 and a Flavivirus in 2015. Which pair correctly identifies these two viruses? A. Chikungunya virus / Zika virus B. Eastern equine encephalitis virus / Dengue virus C. Seadornavirus / Coltivirus D. Sindbis virus / Yellow fever virus
A. Chikungunya virus / Zika virus
Which member of the Herpesviridae that infect humans is the most common viral cause of birth defects (deafness, mental retardation, death) in the United States? A. Cytomegalovirus (human cytomegalovirus) B. Lymphocryptovirus (Epstein-Barr virus) C. Rhadinovirus (human herpesvirus 8) D. Roseolovirus (human herpesvirus 6 or 7) E. Simplexvirus (Herpes simplex virus 1 and 2) F. Varicellovirus (varicella-zoster virus)
A. Cytomegalovirus (human cytomegalovirus)
Which of the following enveloped (−) ssRNA viruses with a monopartite genome is replicated by the host DNA-dependent RNA polymerase? A. Deltavirus (Hepatitis D virus) B. Ebolavirus (Sudan ebolavirus) C. Lyssavirus (Rabies virus) D. Marburgvirus (Marburg marburgvirus) E. Vesiculovirus (Vesicular stomatitis virus)
A. Deltavirus (Hepatitis D virus)
As a research scientist, you have been given the task of determining the number of proteins within a new virus. Intact virions have been observed by electron microscopy to be present in the cytoplasm. Which method would be the best approach to harvest the virions? A. Differential centrifugation on cell homogenate B. Equilibrium centrifugation on cell homogenate C. One-step growth curve with harvest of supernatant D. Protein electrophoresis on the cell homogenate E. Rate zonal centrifugation on cell homogenate
A. Differential centrifugation on cell homogenate
Many viruses use temporal control of transcription, translation and replication. Which method is used by the Polyomaviridae? Transcription from A. Divergent promoters on one DNA strand B. Multiple promoters on both DNA strands C. One promoter with alternative splicing D> Overlapping promoters on one DNA strand
A. Divergent promoters on one DNA strand
Viruses use a variety of secondary genome structure for their transcription, translation, and replication. Which of the following structures allows the virus to control translation of its proteins, producing two different proteins from the same RNA transcript? A. Frame shifting caused by pseudoknots B. Hairpin loops in DNA C. Internal ribosome entry site D. Poly(A) site E. Primer binding site
A. Frame shifting caused by pseudoknots
Between 1997 and 2017, the highly pathogenic avian influenza (HPAI) viruses A(H5N1) and A(H7N9) have emerged into humans several times. Yet, unlike the A(H1N1pdm09)/2009 Influenzavirus A strain that caused a pandemic in 2009-2010, these HPAI strains have not had sustained human-to-human transmission. What is the best explanation for this lack of transmission? A. Hemagglutinin (HA) of HPAI strains prefers to bind to α(2,3)-sialic acid linkages B. M2 channel protein of HPAI strains fails to function in humans C. Neuraminadase (NA) of HPAI strains prematurely cleaves sialic acid of humans D. Nuclear export protein of HPAI strains binds too tightly to nucleocapsids in humans
A. Hemagglutinin (HA) of HPAI strains prefers to bind to α(2,3)-sialic acid linkages
Which of the following statements best describes the composition of the envelopes of viruses? In general, viral envelopes composed of a A. Host lipid bilayer membrane, viral glycoproteins, and host glycoproteins B. Host protein sheath studded with viral glycoproteins C. Viral lipid bilayer membrane, viral glycoproteins, and host glycoproteins D. Viral protein sheath studded with viral glycoproteins E. Viral protein sheath studded with host glycoproteins
A. Host lipid bilayer membrane, viral glycoproteins, and host glycoproteins
Retroviruses have been developed for use as vectors for gene therapy because none were known to cause cancer in humans. However, a Gammaretrovirus (murine leukemia virus) used as a vector carrying the missing btk gene to cure X-linked severe combined immunodeficiency disease caused acute T-cell leukemia in several of the children who received the treatment. What was the mechanism by which this virus caused the leukemia? A. Integration near the LMO2 c-onc gene B. Suppression of apoptosis by an unknown gene C. Transactivation of cellular oncogenes by a protein like Tax D. Transduction of a leukemia oncogene
A. Integration near the LMO2 c-onc gene
Which of the following viruses would be most likely to carry multiple genes encoding proteins whose SPECIFIC (only) functions are to allow evasion of the host immune response (rather than encoding structural proteins or replicative enzymes as well as other functions)? A. Orthopoxvirus: 250 nm in size; 250 kb genome B. Mastadenovirus: 90 nm in size; 35 kb genome C. Enterovirus: 30 nm in size; 7.8 kb genome D. Erythroparvovirus: 22 nm; 5 kb genome E. Deltavirus: 22 nm in size; 1.68 kb genome
A. Orthopoxvirus: 250 nm in size; 250 kb genome
Despite the promise of viral vectors such as adenovirus vectors to deliver genes to correct genetic errors such as the mutation in cystic fibrosis, the majority of products using adenovirus vectors that have been approved for use in different parts of the world are for which of the following? A. To treat cancer B. To treat muscle disorders C. To treat peripheral artery diseases (leg ulcers) D. To vaccinate against infectious disease
A. To treat cancer
In a laboratory experiment to determine the viral attachment protein and the cell surface receptor for a newly described virus causing diarrhea in cats. The virus was tentatively called the feline caliciirus (FCV). The virus has one capsid protein, VP1. Preliminary experiments had identified two possible cell surface receptors: histo-blood group antigen A (HBGA) and the junctional adhesion molecule A (JAM-A). Virions were incubated with saline (no antibody) or the indicated blocking antibody. Following incubation, the virions were placed on cultured cells displaying the indicated surface receptor or receptors. After a suitable incubation, the cultures were examined for the production of FCV progeny virions. Results are shown in the table. A. VP1 is the viral attachment protein and JAM-A is the cell surface receptor B. VP1 is the viral attachment protein and HBGA is the cell surface receptor C. VP1 is the viral attachment protein and both JAM-A and HBGA are cell surface receptors D. VP1 is the viral attachment protein but neither JAM-A nor HBGA is the cell surface receptor E. VP1 is not the viral attachment protein but JAM-A is the cell surface receptor F. VP1 is not the viral attachment protein but HBGA is the cell surface receptor
A. VP1 is the viral attachment protein and JAM-A is the cell surface receptor
In the series of electron micrographs shown, which nucleocapsid(s) exhibit(s) icosahedral symmetry? A. Virus A (Adenovirus) B. Virus B (Ebolavirus Zaire) C. Virus C (Herpes simplex virus 1) D. Virus D (Influenza B virus) E. Virus E (Measlesvirus) F. Virus F (Orf poxvirus) G. Virus G (Paramecium bursaria chlorella virus 1) H. Virus H (SARS-CoV-2 coronavirus)
A. Virus A (Adenovirus) C. Virus C (Herpes simplex virus 1) G. Virus G (Paramecium bursaria chlorella virus 1)
Rhinoviruses are a species within the genus Enterovirus. Unlike most of the members of this genus, Rhinovirus infects only the upper respiratory tract, confining itself mainly to the nose. Why does Rhinovirus not infect the gastrointestinal tract like the other members of the genus? Because Rhinovirus A. cannot withstand stomach acid B. cell surface receptor ICAM-1 is not found in the gastrointestinal tract C. enzymes do not function at temperatures higher than 330C D. is susceptible to alcohol
A. cannot withstand stomach acid
The cell surface molecules DC-SIGN, CLEC5A, and MRC1 are found on macrophages, while only DC-SIGN and MRC1 are found on dendritic cells. Dengue virus infects both types of cells. (See image). A scientist attempting to determine which molecules are used as cell surface receptors by the virus uses antibodies against DC-SIGN and MRC1, separately and together, to block the respective receptors. When only one antibody is used, both dendritic cells and macrophages are infected by dengue virus. When both antibodies are used, only macrophages are infected by dengue virus. (Results also presented in table under image.) What is the best interpretation of these results? Dengue virus can use A. DC-SIGN, CLEC5A, and MRC1 to infect dendritic cells B. DC-SIGN, CLEC5A, and MRC1 to infect macrophages C. Only DC-SIGN to infect macrophages D. Only CLEC5A to infect macrophages E. Only MRC1 to infect macrophages
B. DC-SIGN, CLEC5A, and MRC1 to infect macrophages
A person was infected with a virus that entered the nose (day 1) and replicated (days 2 and 3); sneezing began on day 4 and continued through day 9; the virus spread to the throat on day 5 and replicated (days 6 and 7); pharyngitis and coughing began on day 8 and continued to day 12; all respiratory symptoms had ended by day 12. However, beginning on day 16, the person suffered fever, headache, and stiff neck, indicating that the virus had entered the central nervous system. These symptoms continued through day 22. The person then recovered completely. If this virus can only be spread while the patient is symptomatic, when in the course of the infection in this individual would wearing a mask have been most effective in preventing respiratory transmission of this virus? A. Days 4-9 B. Days 4-12 C. Days 8-12 D. Days 12-22 E.Days 16-22
B. Days 4-12
Whether their entry occurs by clathrin-dependent endocytosis or macropinocytosis, many viruses that must reach the nucleus to complete their replicative cycles use which pathway? A. Caveosome to endoplasmic reticulum B. Dynein transport on microtubules C. Passive diffusion from the plasma membrane to the nucleus D. Propulsive actin tails
B. Dynein transport on microtubules
Papillomaviruses and polyomaviruses can cause cancer when their genomes integrate into host cells resulting in expression of specific proteins. For polyomaviruses, this is the T antigen.Which human papillomavirus protein(s) is/are responsible for causing cancer? A. E1/E2 B. E6 and E7 C. NSP4 D. VP1 and VP3 E. VPg
B. E6 and E7
Double-membrane vesicles, the hallmark of (+) ssRNA virus replication, are usually derived from and found in association with which cellular membrane? A. Cytoplasmic B. Endoplasmic reticulum C. Endosomal D. Golgi E. Mitochondrial F. Nuclear
B. Endoplasmic reticulum
A group of three researchers reported the identification of a new virus class in 1981. They found that the nucleoprotein was located in the in a diffuse band that ranged from 51S to 70S in a sucrose gradient. Using additional techniques, proteins within the diffuse 51S-70S band were recovered in a single band of 1.28 g/cm3 on a cesium chloride gradient. This band was revealed to contain one protein by electrophoresis. Which technique was used to produce the single band of 1.28 g/cm3? A. Differential centrifugation B. Equilibrium (isopycnic) centrifugation C. Rate zonal centrifugation D. Two-dimensional gel electrophoresis
B. Equilibrium (isopycnic) centrifugation
Which of the following proteins is the driver behind syncytium formation by paramyxoviruses? A. Capsid protein B. Fusion protein C. Reverse transcriptase D. RNA-dependent RNA-polymerase E. Scaffolding protein
B. Fusion protein
Post-translational modification of viral proteins assists in targeting those proteins to specific locations within the host cell and, subsequently, the virion. Which modification marks the protein as a viral envelope protein? A. Addition of a nuclear localization signal B. Glycosylation C. Phosphorylation D. Protease cleavage
B. Glycosylation
Integration of the HIV-1 pre-integration complex (PIC) requires the activity of Vpr, the LTRs and integrase encoded by the virus. The host proteins CPSF6 and LEDGF contribute to this integration process as well. What do these proteins contribute? A. Cleave integrase when its function is over B. Guide the PIC to transcriptionally active genes C. Importation of the PIC into the nucleus D. Inhibit of tetherin E. Mediate entry of viral DNA into chromosome
B. Guide the PIC to transcriptionally active genes
Latency for Simplexvirus (Herpes simplex virus 1) is driven in neurons. These cells are non-permissive for infections because a protein is missing from the nucleus of neurons (diagram). During neuronal stress, this protein localizes to the nucleus, allowing transcription of HSV immediate early genes to occur. Which protein is missing in the cell nucleus? A. gH/gL B. HCF1 C. ICP0 D. ICP4 E. VP16
B. HCF1
The coronaviruses that infect humans cause upper and lower respiratory tract disease. One species of the Alphacoronavirus genus Human coronavirus 229E (HCoV-229E) causes only the common cold. Which of the following best explains why this virus is limited to the upper respiratory tract? A. Dryness of the lower respiratory tract in winter prevents HCoV-229E infecting the lung B. HCoV-229E enzymes are active at temperatures between 33°C and 35°C C. HCoV-229E is a defective virus lacking the viral attachment protein on its envelope D. The cell surface receptor for HCoV-229E is not expressed in the lower respiratory tract
B. HCoV-229E enzymes are active at temperatures between 33°C and 35°C
Which bacteriophage uses the level of its pV protein to determine whether the genome is amplified into more replicative forms and used for transcription (pV level is low) or whether it is packaged into progeny virions (pV level is high)? A. Cystoviridae (Cystovirus Pseudomonas virus phi6) B. Inoviridae (Inovirus Escherichia virus M13) C. Microviridae (Sinsheimervirus Escherichia virus phiX174) D. Myoviridae (Tequatrovirus Escherichia virus T4) E. Siphoviridae (Lambdavirus Escherichia virus λ)
B. Inoviridae (Inovirus Escherichia virus M13)
Which virus used CD4 as its main cell surface receptor and CCR5 or CXCR4 as its co-receptor? A. Enterovirus rhinovirus B. Lentivirus human immunodeficiency virus 1 C. Mastadenovirus (human adenovirus) D. Simplexvirus (herpes simplex virus 1)
B. Lentivirus human immunodeficiency virus 1
All of the human herpesviruses cause latent infection after the primary productive infection. Which of the human herpesviruses goes latent in B cells (lymphocytes)? A. Cytomegalovirus (human cytomegalovirus) B. Lymphocryptovirus (Epstein-Barr virus) C. Roseolovirus (human herpesvirus 6 or 7) D. Simplexvirus (Herpes simplex virus 1 and 2) E. Varicellovirus (varicella-zoster virus)
B. Lymphocryptovirus (Epstein-Barr virus)
Dependoparvovirus requires a helper virus to complete its replicative cycle. Without the helper virus, the Dependoparvovirus integrates into the host chromosome or remains in the nucleus as episomes during latency. Which of the following virus serve as helper viruses that can rescue the Dependoparovirus? A. Alphavirus Sinbis virus B. Mastadenovirus type 5 C. Poliovirus 3 D. Rotavirus E. Simplexvirus (HSV1)
B. Mastadenovirus type 5 E. Simplexvirus (HSV1)
Rotavirus infection causes impairment of glucose absorption, changes in chloride secretion, cytoskeletal disruption, and increased water loss from the intestine by the action of which viral protein that acts as an enterotoxin? A. gpV7 B. NSP4 C.V4 D. V5* E. V8*
B. NSP4
The Baltimore classification is based on the form of nucleic acid the virus possesses and which additional characteristic? A. Method of translation of viral proteins B. Pathway for expression of messenger RNA C. Pathway for replication of the genome D. Presence or absence of envelope E. Shape of the nucleocapsid
B. Pathway for expression of messenger RNA
The genome of members of the Herpesviridae is expressed in a temporal manner by the transcription of different parts of the genome at specific times in the replicative cycle. Each set of transcripts is used for synthesis of genes with different functions. Which statement characterizes the proteins produced by the gamma transcripts? A. Their production requires VP16 binding with host Oct-1 and HCF-1 B. They encode the structural proteins C. They include proteins for DNA replication D. They include proteins that inactivate the alpha-genes E. They include transcription factors for late gene transcription
B. They encode the structural proteins
The high mutation rate of Lentivirus HIV-1 allows the virus to escape immune response, develop drug resistance, and change its co-receptor specificity. Mutations in which of these proteins allows HIV-1 to escape neutralizing antibodies? A. gp41 B. gp120 C. Nef D. Protease E. Reverse transcriptase
B. gp120
Erythoparvovirus virions escape the infected cell by lysis. Tiny though it is the virus encodes two proteins that are vital for cell lysis. The NS1 and 11-kDa proteins A. fuse the capsid to the plasma membrane causing lysis B. induce apoptosis resulting in lysis of membranes C. induce autophagy resulting in lysis of membranes D. lyse the nuclear membrane E. lyse the plasma (cytoplasmic) membrane
B. induce apoptosis resulting in lysis of membranes
Quarantine means... A. going to class but not parties B. keeping an exposed individual from others C. reducing the size of gatherings D. social distancing E. using barrier precautions
B. keeping an exposed individual from others
If the genome of a member of the Parvoviridae has inverted repeats (like those of Bocaparvovirus, Dependparvovirus, and Erythroparvovirus), which of the following is most characteristic of the progeny virions? A. 99% are (+) ssDNA and 1% are (−) ssDNA B. 99% are (−) ssDNA and 1% are (+) ssDNA C. 50% are (+) ssDNA and 50% are (−) ssDNA D. 25% are (+) ssDNA and 75% are (−) ssDNA
C. 50% are (+) ssDNA and 50% are (−) ssDNA
The development of circulating vaccine-derived poliovirus strains that cause acute flaccid paralysis has occurred multiple times, especially in African and Asian countries. Which two of the listed items have led to the development of such strains of poliovirus? A. Ability of the virus to evade neutralizing antibodies B. Ability of the virus to use reassortment C. Ability of the virus to use template switching during replication D. Use of a DNA vaccine for poliovirus E. Use of Sabin oral trivalent poliovirus vaccine F. Use of Salk injected trivalent poliovirus vaccine
C. Ability of the virus to use template switching during replication E. Use of Sabin oral trivalent poliovirus vaccine
Which one of these individuals is MOST likely to develop chronic hepatitis B after becoming infected with Orthohepadnavirus (HBV)? A. A 42-year-old healthcare worker B. An adult who traveled to China C. An eighteen-month-old toddler D. A previously healthy 23-year-old man E. A prison inmate who is 64 years old
C. An eighteen-month-old toddler
The molecular switch that governs the decision between the lytic cycle and lysogeny in λ phage involves the relative increase of one viral protein over another. When the λ phage enters a cell and transcription and translation of its early proteins begins, what is the signal for LYSOGENY? A. CI greater than CII B. CII greater than CI C. CII greater than Cro D. Cro greater than CII E. Cro greater than N F. N greater than Cro
C. CII greater than Cro
For every host immune response, there is at least one virus that can evade that response. Which of the following is a mechanism by a virus can evade host production of a specific antibody? A. Block production of interferon-α/β B. Carry an ortholog or homolog of BCL-2 C. Change the target protein (mutation) D. Prevent the appropriate expression of MCH class I E. Stimulate autophagy
C. Change the target protein (mutation)
Which of the following factors would be most likely to promote transmission of a respiratory virus (spread by respiratory aerosols or airborne transmission)? A. Being bitten by an infected animal B. Maintaining stringent handwashing C. Failing to cover a cough or sneeze D. Swimming every day E. Working outdoors away from other people
C. Failing to cover a cough or sneeze
While both naked and enveloped viruses can enter host cells by several different pathways, which method of entry is unique to the enveloped viruses? A. Caveolin-mediated endocytosis B. Clathrin-mediated endocytosis C. Fusion with the plasma membrane D. Injection of the genome through a pore
C. Fusion with the plasma membrane
Considering that protective antibody can block the ability of a virus to attach to its cell surface receptor, which of the following labelled structures in the diagram of the virus would be most likely to elicit generation of such an antibody? A. Capsid protein B. dsDNA genome C. Glycoprotein spike on viral envelope D. Portion of the lipid bilayer membrane E. Viral DNA-dependent DNA polymerase
C. Glycoprotein spike on viral envelope
Which of the Herpesviridae that infect humans is the most common viral cause of birth defects in the United States today? A. Epstein-Barr virus B. Herpes simplex virus 2 C. Human cytomegalovirus D. Human herpes virus 6 E. Kaposi sarcoma-associated herpesvirus
C. Human cytomegalovirus
Viral capsids often appear to be geometrically regular shapes. The symmetry of the virus shown in the electromicrograph and accompanying diagram is best described by which term? A. Cone B. Helix C. Icosahedron D. Rod
C. Icosahedron
A filamentous bacteriophage was the first one to be developed as a cloning vector for DNA sequencing in 1977. Later, the phage vector was adapted to be phagemid vector (pBluescriptII) that had many more features. Which bacteriophage was used? A. Allolevivirus Qbeta B. Cystovirus Pseudomonas phage phi6 C. Inovirus Escherichia virus M13 D. Lambdavirus Escherichia virus λ phage E. Teseptimavirus Escherichia virus T7
C. Inovirus Escherichia virus M13
The bacteriophage genome shown illustrates coupled translation and replication due to RNA secondary and tertiary structure. Which virus uses this mechanism in its replication? A. Cystovirus (Pseudomonas virus phi6) B. Inovirus (Escherichia virus M13) C. Levivirus (MS2 phage) D. Sinsheimervirus (Escherichia virus phiX174) E. Tequatrovirus (Escherichia virus T4)
C. Levivirus (MS2 phage)
Genome sequences are now being used to classify, and reclassify, viruses into families, genera, and species. As shown in the unrooted phylogenetic tree for the family Picornaviridae, Rhinoviruses have been placed as a species within the genus Enterovirus (white circle with dotted outline) due to their sequence relatedness. Which of the following is the correct conclusion regarding the placement of the three newly sequenced species with the proposed name Rosavirus (black circle)? A. Like Rhinovirus, Rosavirus belongs in the Enterovirus genus (top left) B. Rosavirus should be included with the Aphthovirus genus (middle right) C. Like Hepatovirus, Rosavirus should be its own genus (bottom right) D. Rosavirus should be placed in the Parechovirus genus (bottom left) E. Rosavirus should be placed in a totally different family
C. Like Hepatovirus, Rosavirus should be its own genus (bottom right)
Which of the following viruses would most likely be resistant to detergents? A. Enveloped coronavirus B. Enveloped cytomegalovirus C. Naked adenovirus D. Naked enterovirus
C. Naked adenovirus D. Naked enterovirus
Transmission of the Baculovirus involves the production of which structure to protect the virions once they are outside the host insect? A. Egg cases B. Inclusion bodies C. Occlusion bodies D. Sporosori E. Vesicles
C. Occlusion bodies
A member of the Reoviridae family was investigated for its role as a potential anticancer agent. Which of the following viruses has been marketed as REOLYSIN, an agent that preferentially mediates apoptosis in transformed (cancerous) cells? A. Dependoparvovirus B. JC polyomavirus C. Orthoreovirus D. Rotavirus E. Seadornavirus
C. Orthoreovirus
Once the precapsids of Cystovirus Pseudomonas virus phi6 have formed, a packaging protein translocates the three (+) ssRNA genomic segments into the capsid in a specific order, S—M—L. Which protein is the packaging protein? A. P2 RdRp B. P3 spike protein C. P4 NTPase D. P5 peptidoglycan hydrolase E. P6 fusion protein
C. P4 NTPase
The Poxviridae cause diseases in many different types of mammals, reptiles, birds, fish and insects. Which virus causes a zoonotic poxvirus disease that is spread to humans by contact with the animal? A. Alphaentomopoxvirus B. Molluscipoxvirus C. Parapoxvirus D. Variola virus
C. Parapoxvirus
The Alphavirus genus of the Togaviridae family and the Flavivirus genus of the Flaviviridae family contain species that are transmitted by arthropods and that cause encephalitis. Most of these virus species are transmitted by mosquitoes. Which of the following is transmitted by ticks? A. Eastern equine encephalitis virus B. Japanese encephalitis virus C. Powassan virus D. St. Louis encephalitis virus E. West Nile virus
C. Powassan virus
From the time of inoculation of Lyssavirus (Rabies virus), it may take a month to a year (average 90 days) for the virus to cause initial symptoms but once symptoms appear, rabies progresses rapidly to fatality. Why is the incubation period so long in most cases? A. During replication, the majority of the progeny Rabies virus virions are defective B. Rabies virus must replicate in muscle, then in lymph nodes, and disseminate by viremia to reach the brain C. Rabies virus replicates slowly in muscle tissue and passively ascends via sensory fibers D. Rabies virus replicates slowly in the dorsal root ganglion and passively ascends the spinal cord
C. Rabies virus replicates slowly in muscle tissue and passively ascends via sensory fibers
Before the arrival of West Nile virus in the United States in 1999 and its spread across the country over the next few years, which virus that causes encephalitis was found in the US that uses the same vector and the same reservoir? A. Japanese encephalitis virus B. Powassan virus C. St. Louis encephalitis virus D. Venezuelan equine encephalitis virus
C. St. Louis encephalitis virus
Which statement concerning viruses that use reverse transcriptase is most accurate? A. The genomes of these viruses are dsDNA B. The genomes of these viruses are ssRNA C. The host DNA-dependent RNA polymerase II produces the RNA genome or intermediate D. The host reverse transcriptase enzyme must convert the genome to dsDNA as the first step E. The viruses must integrate into the host chromosome for replication to be possible
C. The host DNA-dependent RNA polymerase II produces the RNA genome or intermediate
Of the properties of viruses listed below, which one makes them unique among all other life forms? A. They are filterable. B. They are dependent on the host cell for energy production. C. They are dependent on the host cell for protein synthesis. D. They are obligate intracellular parasites. E. They must use the host DNA polymerase for genome replication.
C. They are dependent on the host cell for protein synthesis.
Among the Flaviridae, which virus listed causes hemorrhagic fever with a high mortality rate? A. Powassan virus B. West Nile virus C. Yellow fever virus D. Zika virus
C. Yellow fever virus
Compared to the Herpesviridae, the Poxviridae have larger genomes and encode more proteins. Why do the Poxviruses require so many more proteins? Their genomes must encode all the proteins required for A. ATP production B. construction of a lipid bilayer membrane C. mRNA synthesis and DNA synthesis D. the translation machinery
C. mRNA synthesis and DNA synthesis
etroviruses begin their replicative cycle by transcribing their RNA genomes into ssDNA and then dsDNA. Priming is required to initiate DNA synthesis, yet eukaryotic primases that produce RNA primers are found only in the nucleus. Furthermore, the retroviruses do not encode or carry a viral primase. What do these viruses use to initiate DNA synthesis? A. Hairpin loop priming B. Okazaki fragments C. tRNA molecule stolen from host D. Viral protein
C. tRNA molecule stolen from host
For the following 4 questions, match the virus to its description found in the lettered list below. Coltivirus Erythroparvovirus Hepatovirus West Nile virus (Flavivirus) A. (+) ssRNA virus with naked icosahedral form and quasi-enveloped icosahedral form B. Enveloped (+) ssRNA virus with icosahedral nucleocapsid C. Enveloped dsDNA virus with complex nucleocapsid D. Naked (+) ssRNA virus with icosahedral nucleocapsid E. Naked virus with icosahedral nucleocapsid with 3 shells (capsids) and 12 segments of dsRNA F. ssDNA virus with naked icosahedral nucleocapsid
Coltivirus - E. Naked virus with icosahedral nucleocapsid with 3 shells (capsids) and 12 segments of dsRNA Erythroparvovirus - F. ssDNA virus with naked icosahedral nucleocapsid Hepatovirus - A. (+) ssRNA virus with naked icosahedral form and quasi-enveloped icosahedral form/ D. Naked (+) ssRNA virus with icosahedral nucleocapsid West Nile virus (Flavivirus) - B. Enveloped (+) ssRNA virus with icosahedral nucleocapsid
HIV-1 infection of which cell leads to loss of immune functions and the condition known as AIDS (acquired immunodeficiency syndrome)? A. Natural killer cell B. Macrophage C. CD8+ T cell D. CD4+ T cell E. B cell
D. CD4+ T cell
Viruses that do not encode capping enzymes or that cannot use the host capping enzymes use which alternative method for preparing their mRNAs for translation? A. 5 -VPg protein B. Alternative splicing C. Attached host tRNA molecule D. Cap snatching E. Polyadenylation
D. Cap snatching
What features of Orthohepadnavirus (Hepatitis B virus) replication are associated with the development of hepatocellular carcinoma (HPC)? A. Chronic infection only B. Integration of the HBV genome only C. Production of truncated HBx protein only D. Chronic infection, integration, and truncated HBx are all associated with HPC discrimination E. HPC is associated with acute infection only
D. Chronic infection, integration, and truncated HBx are all associated with HPC discrimination
What step occurs FIRST in the replicative cycle of the rotavirus? A. Binding of VP5* to integrins B. Binding of VP8* to sialic acid C. Clathrin-mediated endocytosis D. Cleavage of VP4 by host intestinal trypsin protease E. Permeabilization of host endosomal membrane by gpV7
D. Cleavage of VP4 by host intestinal trypsin protease
In the diagram shown, which wall (or block) represents components of adaptive immunity? A. A - Ciliary elevator, intestinal mobility, urinary flow B. B - APOBEC3 proteins, Interferon-Alpha/Beta, Apoptosis C. C - Complement, Natural killer cells, Tetherin D. D - Pathogen-specific antibodies, Helper T cells (CD4), Cytotoxic T cells (CD8)
D. D - Pathogen-specific antibodies, Helper T cells (CD4), Cytotoxic T cells (CD8)
In 2002, scientists generated infectious, neurovirulent poliovirus virions in the absence of any natural template. This was done by using a poliovirus A. RNA genome purified from poliovirus-infected cell culture B. cDNA genome reverse transcribed from purified poliovirus RNA c. RNA genome transcribed from the cDNA genome by T7 bacteriophage RNA polymerase D. DNA genome assembled from oligonucleotides
D. DNA genome assembled from oligonucleotides
The SARS-CoV-2, as a species of Betacoronavirus, attaches to the ACE2 molecule on the host cell by its spike protein S. However, for the virus to enter the cell, the S protein must be cleaved twice by host proteins. The first cleavage allows endocytosis and the second exposes the fusion protein. Which host proteins provide these services for SARS-CoV-2? A. APOBEC3 and MX2 B. ESCRT proteins TSG101 and ALIX C. HAVCR1 (TIM1) and NPC1 D. Furin and TMPRSS2 E. NSP4 and NSP6
D. Furin and TMPRSS2
Most adenovirus infections are self-limiting and resolve in one to two weeks. In which population can adenovirus infection lead to pneumonia, hepatitis, kidney failure, and death? A. Adolescents (11-19) B. Children (3-10 years) C. Elderly people (over 65 years) D. Immunocompromised, any age E. Military recruits (young adults)
D. Immunocompromised, any age
Of the species of the Bunyavirales order and families Peribunyaviridae, Phenuiviridae, Hantaviridae, and Arenaviridae that are found in the United States, which are spread by rodent vectors rather than by arthropod vectors? A. Heartland phlebovirus (Phlebovirus) B. Jamestown Canyon virus (Orthobunyavirus) C. La Crosse virus (Orthobunyavirus) D. Lymphocytic choriomengitis mammarenavirus (Mammarenavirus) E. Sin Nombre orthohantavirus (Orthohantavirus)
D. Lymphocytic choriomengitis mammarenavirus (Mammarenavirus) E. Sin Nombre orthohantavirus (Orthohantavirus)
Enterovirus coxsackievirus B produces a paracrystalline array containing thousands of virions (shown in image) in the cell cytoplasm. What is the mechanism by which these naked virions are released? A. Actin-mediated outward transport B. Budding C. Exocytosis D. Lysis
D. Lysis
In order to move from their site of entry to their preferred site of replication, many viruses take advantage of which cell structure? A. Cytoskeletal actin fibers B. Golgi complex C. Lysosome D. Microtubules E. Secretory vesicles
D. Microtubules
Bacteriophages are found throughout the natural environment. In which of the following are the highest numbers of bacteriophages found? A. Antarctic soil B. Foods that ferment naturally C. Human gastrointestinal tract D. Ocean water
D. Ocean water
Which of the following viruses is a (−) ssRNA virus with a segmented genome that causes Hantavirus cardiopulmonary syndrome in the New World? A. Mammarenavirus Lymphocytic choriomeningitis mammarenavirus B. Orthobunyavirus La Crosse orthobunyavirus C. Orthohantavirus Hantaan orthohantavirus D. Orthohantavirus Sin Nombre orthohantavirus E. Phlebovirus Rift Valley fever phlebovirus
D. Orthohantavirus Sin Nombre orthohantavirus
Which of the following is a quasi-enveloped (+) ssRNA virus that causes hepatitis that is often fatal in pregnant women? A. Hepatovirus B. Mamastrovirus C. Orbivirus D. Orthohepevirus E. Orthoreovirus
D. Orthohepevirus
Recovering infectious virions from (−) sense RNA genomes is more difficult than recovering virions from viruses whose genomes are infectious, like the dsDNA genomes and (+)ssRNA = mRNA genomes. The process developed to study the importance of specific viral genes or the impact of gene mutations on protein function, known as "reverse genetics," was first used with the Vesiculovirus (a laboratory substitute for Lyssaviruss). To recover infectious Vesiculovirus progeny virions requires use of a plasmid expressing the (−) ssRNA genome. What else is required to recover infectious virions? A. A plasmid expressing the nucleocapsid protein only B. A plasmid expressing the phosphoprotein only C. A plasmid expressing the RNA polymerase only D. Plasmids expressing the nucleocapsid protein, the phosphoprotein, and the RNA polymerase E. Nothing else is required, the RNA genome expression plasmid is sufficient
D. Plasmids expressing the nucleocapsid protein, the phosphoprotein, and the RNA polymerase
The reverse transcriptase of HIV-1 incorporates mutations into the viral genome at a rate of one mutation in every replication of the genome. Which of the following can be the result of this mutability? A. A new species of HIV-1 develops monthly B. Cross-resistance to all drugs C. Gains ability to cross the blood-brain barrier D. Quasispecies formation E. Resistance to a drug BEFORE the drug is used F. Shift from R5 to R5X4 or X4 coreceptor usage G. Shift in host range to felines and canines
D. Quasispecies formation E. Resistance to a drug BEFORE the drug is used F. Shift from R5 to R5X4 or X4 coreceptor usage
In the viral replicative cycle, which step comes last? A. Assembly B. Attachment C. Entry D. Release of virions E. Replication of the genome F. Transcription of mRNA G. Translation of proteins
D. Release of virions
The Betacoronavirus species that infect humans cause respiratory tract disease that varies from mild upper respiratory tract infections to acute respiratory distress syndrome and death. Which of these species of Betacoronavirus is no longer causing disease anywhere in the world? A. Betacoronavirus 1 (HCoV-HKU1) B. Embecovirus (HCoV-OC43) C. Merbecovirus (MERS-CoV) D. Sarbecovirus (SARS-CoV-1) E. Sarbecovirus (SARS-CoV-2)
D. Sarbecovirus (SARS-CoV-1)
The Baltimore classification describes which of the following? A. The mechanism by which mRNA is translated into proteins B. The mechanism by which viral RNA genomes are replicated C. The site at which the viral genome is replicated D. The steps needed for mRNA to be produced from the viral genome
D. The steps needed for mRNA to be produced from the viral genome
The members of the Reoviridae family are classified into subfamilies, either Spinareovirinae or Sedoreovirinae, and genera based on the number of shells in the capsid, the number of segments in the genome and the presence or absence of which additional feature? A. Enterotoxin protein B. Envelope C. Proteins in the polymerase complex D. Turrets
D. Turrets
Viruses use different methods for release from the host cell during the final steps in budding. Which method uses only viral proteins to engineer the release? A. Actin propulsive tails used by Orthopoxvirus B. ESCRT complex used by Ebolavirus C. Nanotubule bridging conduits used by human immunodeficiency virus-1 D. Viroporin used by Influenzavirus
D. Viroporin used by Influenzavirus
Of the following viruses, which has the widest range of endemicity in the Unites States? A. Dengue virus B. Powassan virus C. St. Louis encephalitis virus D. West Nile virus E. Zika virus
D. West Nile virus
In the following situations in which a virus transmitted to a human, which of the following best defines vector transmission? The virus was transmitted ... A. by a person with a subclinical infection B. by ingestion of improperly cooked food C. by someone who is chronically infected D. by the bite of an infected arthropod E. via contact with a contaminated computer keyboard
D. by the bite of an infected arthropod
Comparing the genomes of Alphavirus and Flavivirus and their transcription and translation, which of the following is unique to the Alphavirus genus? A. A subgenomic mRNA is used to interfere with host antiviral response B. Genome is 5'-capped and has a 3'-terminal stem-loop structure C. Genome serves as mRNA D. mRNA is temporally translated into two sets of two polyproteins E. Viral and host proteases cleave the polyproteins into individual proteins
D. mRNA is temporally translated into two sets of two polyproteins
Which of the following is characteristic of prokaryotic transcription versus eukaryotic transcription? Prokaryotic transcription ... A. includes the addition of a 5' 7-methylguanosine cap. B. initiates at the TATA box. C. often produces transcripts contain introns and require splicing. D. terminates by Rho-dependent or -independent mechanisms. E. uses leaky scanning to produce two transcripts from a bicistronic message.
D. terminates by Rho-dependent or -independent mechanisms.
Which of the following processes related to transcription of RNA and translation of mRNA can only take place in the nucleus? A. Polyadenylation B. Leaking scanning C. Frame shifting D. Cap snatching E. Alternative splicing
E. Alternative splicing
Which of the proteins on the labeled diagram of the HIV-1 virion have been acquired from the host? A. Integrase B. Reverse transcriptase C. Protease D. tRNA lys E. CypA F. MHC class II G. gp120-gp41 H. ICAM-1 I. Vpr J. Matrix
E. CypA F. MHC class II H. ICAM-1
In the process of RNA silencing (as an antiviral mechanism used by plants), siRNAs 21-25 bp long are produced that result in destruction of mRNAs, both cellular and viral. Which cellular enzyme is involved in the initial step of cleaving dsRNA? A. RNAse L B. RNA-dependent RNA polymerase C. RISC complex D. Protein kinase R E. Dicer F. 2'-5'(A) synthetase
E. Dicer
The antiviral state induced by interferon α/β is a major immune mechanism by which the eukaryotic host cell can not only defeat a virus trying to replicate within that cell, it also primes nearby cells to resist infection. Consequently, viruses have many mechanisms of evading this particular immune response. Which of the following mechanisms of immune evasion is/are used by viruses to evade interferon α/β? A. Blockage of signaling pathways leading to interferon production B. Blocking the pathway that activates protein kinase R (PKR) C. Inhibition of host ability to synthesize its own proteins D. Preventing activation of RNase L by 2'-5'-oligoadenylate synthetase E. Different viruses use all of the mechanism described
E. Different viruses use all of the mechanism described
Two viruses have recently been shown to be quasi-enveloped; that is, the virion is surrounded by a host-derived lipid membrane that does NOT contain any viral proteins. Both cause the same type of infection. What infection do these two viruses cause? A. Common cold B. Encephalitis C. Hand-foot-and-mouth disease D. Hemorrhagic fever E. Hepatitis
E. Hepatitis
Infection with Rubivirus (rubella virus) manifests in different ways in different age groups. Which of the following is characteristic of congenital rubella syndrome? A. Fever without rash plus bleeding from thrombocytopenia B. Rash with fever lasting 3 days C. Rash with fever plus arthritis and arthralgia D. Rash with fever and generalized swollen lymph nodes E. Rash without fever plus heart defects, cataracts and hearing loss
E. Rash without fever plus heart defects, cataracts and hearing loss
Over time, the use of the oral polio vaccine containing three attenuated strains of the Poliovirus has resulted in cases of acute flaccid paralysis similar to the original disease (poliomyelitis) caused by the polioviruses. Which of the following processes is responsible for appearance of pathogenic circulating vaccine-derived poliovirus? A. Mutations in envelope proteins B. Mutations in the VP1-VP3 canyon proteins C. Presence of defective interfering particles D. Reassortment E. Recombination by template switching
E. Recombination by template switching
During its assembly, the double-layered particle of Rotavirus gains an envelope by passage through which membrane? A. Cytoplasmic B. Endosomal C. Golgi D. Nuclear E. Rough endoplasmic reticulum
E. Rough endoplasmic reticulum
The Sinsheimervirus Escherichia virus phiX174 has two forms of capsid, an immature procapsid and the mature virion capsid. Two proteins indicated by arrows on the procapsid are removed during packaging of the genome and one protein is added to produce the mature virion. What are the two proteins that are removed? A. Accessory proteins B. Packaging proteins C. Pilot proteins D. Replication proteins E. Scaffolding proteins
E. Scaffolding proteins
The Rabies virus and other members of the Lyssavirus genus, as well as all (−) ssRNA viruses except the Deltavirus, control the amount of each protein produced by using which process? A. Coupling of replication and transcription B. Coupling of replication and translation C. Coupling of transcription and translation D. Production of subgenomic mRNAs E. Sequential transcription
E. Sequential transcription
Among the populations listed below, who should receive the Hepatitis B virus vaccine? A. Health care workers only B. Infants born to mothers infected with Hepatitis B virus only C. People in prison only D. People with Hepatitis C virus infection only E. The groups listed in A, B, C, and D should have the Hepatitis B virus vaccine F. None of those groups need the Hepatitis B virus vaccine
E. The groups listed in A, B, C, and D should have the Hepatitis B virus vaccine
Much of the work that established viruses as a filterable agent that transmitted a specific disease was performed in the late 1800s and early 1900s using the Chamberland filter. Later, researchers were able to demonstrate the rod-shaped forms of the crystalized virus using the newly developed electron microscope. Still later, researchers showed that combining the genomic RNA and the capsid proteins resulted in complete virions. Which virus was studied? A. Ebolavirus B. Hepatitis C virus C. Poliovirus D. SARS coronavirus-1 E. Tobacco mosaic virus
E. Tobacco mosaic virus
Genomic replication of members of this virus family takes place in large cytopathic vacuoles housing numerous spherules. Recently, one member of this family has been shown to form even larger cytopathic vacuoles that carry multiple encapsidated genomes on the outside and even more hexagonal lattices of envelope proteins. (Diagram) A. Caliciviridae B. Flaviviridae C. Picornaviridae D. Reoviridae E. Togaviridae
E. Togaviridae
COVID-19, the disease caused by SARS-CoV-2, takes many different forms from asymptomatic to deadly. Recently, papers have been published regarding the presence of autoantibodies in 10% of the individuals who develop severe COVID-19. What host protein is the target of these autoantibodies?" A. Angiotensin I converting enzyme 2 (ACE2, found on many cell types) B. MHC class I (necessary for cytotoxic T cell response) C. Myelin (protein forming a sheath round nerves) D. Surfactant protein A (produced in the lungs) E. Type I interferon (necessary for initiating the antiviral state)
E. Type I interferon (necessary for initiating the antiviral state)
All members of the Herpesviridae cause latent infections. Which one becomes latent in neurons within the sensory and cranial ganglia? A. Cytomegalovirus (human cytomegalovirus) B. Lymphocryptovirus (Epstein-Barr virus) C. Rhadinovirus (Kaposi s sarcoma-associated herpesvirus) D. Roseolovirus (human herpesvirus 6 or 7) E. Varicellovirus (varicella-zoster virus)
E. Varicellovirus (varicella-zoster virus)
An Influenzavirus is isolated from a patient with pneumonia. After several passages (subcultures), this enveloped, segmented (−) ssRNA virus no longer replicates its genome. Sequencing analysis reveals the virus has lost a critical gene? Loss of which of the following is most likely responsible for this failure to replicate? The gene that encodes the A. Hemagglutinin envelope glycoprotein B. Neuraminadase envelope glycoprotein C. Viral DNA-dependent RNA polymerase D. Viral reverse transcriptase see C E. Viral RNA-dependent RNA polymerase
E. Viral RNA-dependent RNA polymerase
Of the Flavivirus species listed that infect humans, which has humans ONLY as its reservoir and host? A. Dengue virus B. St. Louis encephalitis virus C. West Nile virus D. Yellow fever virus E. Zika virus
E. Zika virus
Based on the information in the table from experiments using antibodies to block different HSV-1 attachment proteins, which protein(s) are necessary for fusion of the HSV-1 virion with the cell plasma membrane? A. gB alone B. gC alone C. gD alone D. gH/gL alone E. gB plus gH/gL F. gC plus gD
E. gB plus gH/gL
The study of viruses has led to an increase in knowledge in the fields of molecular biology, cell biology, and cancer biology. Which of the following best describes virology? Discovery of A. Evidence that genes are DNA B. Introns C. RNA pseudoknots D. The first transcription factor E. The first nuclear localization signal F. None of these were learned from virology G. Choices A, B, C, D, and E were learned from virology
G. Choices A, B, C, D, and E were learned from virology
Match following bacteriophages with their families: Shinsheimervirus Escherichia virus phiX174 Teseptimavirus T7 phage Lambdavirus Lamda phage A. Autographiviridae B. Inoviridae C. Microviridae D. Cystoviridae E. Siphoviridae F. Leviviridae
Shinsheimervirus Escherichia virus phiX174 - C. Microviridae Teseptimavirus T7 phage - A. Autographiviridae Lambdavirus Lamda phage - E. Siphoviridae
