Virology Practice Test 32 Questions with Verified Answers,100% CORRECT

Virology Practice Test 32 Questions with Verified Answers The difference between "simple" retrovirus and "complex" retrovirus is? A) "Simple" retroviruses do not cause disease B) "Complex" retroviruses contain additional genes called accessory genes C) "Simple" retroviruses do not cause tumors D) "Complex" retroviruses carry viral oncogene E) Only "complex" retroviruses produce provirus - CORRECT ANSWER B, E What is the first biosynthetic event that occurs in cells infected with dsDNA viruses? A) Membrane fusion B) Protein synthesis C) Transcription D) DNA replication - CORRECT ANSWER C Which statement about polyadenylation of DNA virus mRNAs is correct? A) It always occurs in the cytoplasm B) Occurs after cleavage of pre-mRNA C) Poly(A) added at the 5' end of pre-mRNA D) Specified by a stretch of U residues in template - CORRECT ANSWER B In the rolling circle method of DNA replication: A) both strands of DNA in the circle are nicked B) RNA is nicked C) one strand of DNA in the circle is nicked D) 5' tail of DNA is nicked - CORRECT ANSWER C Negative-sense RNA viruses require which of the following enzymes for their replication? A) DNA dependent RNA polymerase B) Reverse transcriptase C) RNA dependent RNA polymerase D) RNA dependent DNA polymerase - CORRECT ANSWER C What is the first biosynthetic event that occurs in cells infected with negative-sense RNA viruses? A) Transcription B) Genome replication C) Protein synthesis D) Membrane fusion - CORRECT ANSWER A Which of the following statements concerning viral RNA synthesis is INCORRECT? A) The RNA genome must be copied end to end B) mRNAs must be produced that can be translated by the cell C) A viral RNA polymerase copies the viral RNA genome D) A positive-strand viral RNA must enter the cell together with an RNA polymerase - CORRECT ANSWER D In retrovirus replication, (Baltimore class VI), reverse transcription describes which one of the following: A) Converting viral RNA into proteins B) Converting viral RNA into DNA C) Converting viral DNA into RNA D) Converting proteins into viral RNA - CORRECT ANSWER B Protease inhibitors are a powerful group of anti-retroviral drugs which effectively: A) prevent viral genome integration into host chromosome B) block translation of viral mRNA C) inhibit reverse transcriptase D) inhibit post-translational cleavage of viral capsid proteins - CORRECT ANSWER D Which of the following are characteristic of inhibition of cellular gene expression by viral proteins? A) Inhibition of cellular pre-mRNA production B) Inhibition of polyadenylation of cellular pre-mRNA C) Inhibition of splicing of cellular pre-mRNA D) Inhibition of export of cellular mRNAs from the nucleus E) Inhibition of translation of cellular mRNAs F) Initiation of degradation of cellular mRNA - CORRECT ANSWER E Lipid droplets are depots for the storage of fatty acids in the form of triacylglycerols but in the following virus-infected cells, they are repurposed for assembly of virus particles A) HEP-C virus infected cells B) Rotavirus infected cells C) Poliovirus infected cells D) Poxvirus infected cells - CORRECT ANSWER A Which of the following statements about virus-host cell interactions is true? A) In a latent virus infection, the cell survives and the virus genome is lost B) In a latent virus infection, the cell survives and continuously produces virus at low levels C) In a latent virus infection, the virus genome persists but no complete virus particles are produced D) In a latent virus infection, the virus genome persists and the cell is transformed - CORRECT ANSWER True or False: replication of RNA virus genomes is accompanied by a low mutation rate because RNA-dependent RNA polymerases possess proofreading activity - CORRECT ANSWER True or False: influenza virus particles are released from infected cells via ESCRT-dependent budding - CORRECT ANSWER True or False: plant cells have no receptors for virus on their surface - CORRECT ANSWER true Inhibition of cellular gene expression by virus proteins Identify one viral gene product that: a. Regulates alternative splicing b. Inhibits splicing c. Suppresses polyadenylation at specific sites d. induces mRNA degradation e. Regulates RNA export from the nucleus - CORRECT ANSWER Matching: 1. Coronaviruses 2. Empty particle 3. ATPase motor 4. Lysogen 5. Herpesviruses 6. DNA primase 7. Chemokine receptor 8. Plasmodesmata 9. Bacteria lysis 10. Lipid droplets A. holin-endolysin pathway B. RNA primers C. Hepatitis C virus D. HIV E. viral genome expression F. nested set of mRNAs G. Tegument H. Prophage I. Type II Genome packaging system J. movement proteins - CORRECT ANSWER 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. Define replicative intermediate - CORRECT ANSWER - characteristic of viral RNA replication - several RNA molecules are transcribed simultaneously from a single RNA template - the "antigenome" or (−) strand, which serves as a template for viral RNA synthesis Define complex retroviruses - CORRECT ANSWER - have additional genes - have evolved mechanism for nuclear entry in non-dividing cells - example: HIV Define LTRs - CORRECT ANSWER - long terminal repeats - Define pseudodiploid - CORRECT ANSWER - retrovirus genome is diploid since 2 RNA genomes are encapsidated - only 1 copy of integrated retroviral DNA is detected after infection by a single particle Define polycistronic mRNA - CORRECT ANSWER - virus gene codes for 2 or more proteins from 1 mRNA - ex. + sense RNA viruses Define virological synapses - CORRECT ANSWER specialized sites intercellular contact that form when infected cells contact uninfected neighbouring cells;results in intercellular transfer of virus Define lysogen - CORRECT ANSWER a bacterium containing a prophage Define cytopathic effects - CORRECT ANSWER changes in cell morphology caused by infecting virus Define inclusion bodies - CORRECT ANSWER - aka viroplasm - where viral replication and assembly occurs Define virus persistence - CORRECT ANSWER those in which the virus is not cleared from the host following primary infection but remains associated with specific cells For the "simple" retroviruses that rely on cell division to enter the nucleus, how does the viral genome remain in the nucleus once cell division is completed? - CORRECT ANSWER Some RNA-dependent RNA polymerases require a primer to initiate RNA synthesis. What are the two different types of primer used for RNA synthesis? - CORRECT ANSWER - protein or capped primer - Which enzyme produces viral mRNAs in a cell infected with retrovirus? - CORRECT ANSWER How do enveloped plant viruses exit plant cells? - CORRECT ANSWER - can leave in 2 ways - encapsidated viruses leave via vector or virus moves as virion/RIC into next cell via plasmodesmata - enveloped forms are not transported to neighbouring cells Consider a virus with a (+) strand RNA genome 8 kb in length, which encodes eight proteins. Which of the following is a known mechanism for producing all eight proteins from this genome? A) A single polyprotein is synthesized, which is then processed by proteases to form eight proteins B) The RNA is cleaved into eight fragments, each of which is translated into a different protein C) Immediately upon entering the cells, the viral RNA polymerase that is carried into the cell within the virus particle produces eight subgenomic mRNAs from the (+) strand RNA genome D) There is no way to produce multiple proteins from a eukaryotic RNA - CORRECT ANSWER A