Virology Exam 2 Study Guide
Which of the following is the most logical explanation behind the naming "reverse transcriptase" A. Because of the enzyme's ability to reverse the flow of the genetic information B. Because of the enzyme's ability to synthesize the RNA from the DNA in a reverse order using 5′end of the RNA as the initiation site D. All of the other statements are correct logics behind the naming E. Because of the enzyme's ability to reverse the process of translation followed by transcription
A
How is DNA replication of parvovirus and adenovirus similar? A. Replication occurs by strand displacement B. They both require protein-linked primers C. A replication fork forms at the origin of replication D. None of the above
A
The catalytic site of the RNA dependent RNA polymerase is present in which of the following domain? A. The Palm B. The Thumb C. The Finger D. The knuckle
A
Which is a universal rule about RNA directed RNA synthesis? A. RdRp may initiate de novo or require a primer B. RNA synthesis initiates randomly on the RNA template C. RNA is synthesized in a 3'-5' direction D. RNA synthesis is always template-directed
A
Which of the following define the most logical function of reverse transcriptase in most cases (ignoring the few exceptions)? A. It is an RNA dependent DNA polymerase B. It is a DNA dependent RNA polymerase C. It is an RNA dependent RNA polymerase D. It is a DNA dependent DNA polymerase
A
Which of the following group of viruses usually pack RNA dependent RNA polymerase in the virus particle? A. Both A and C are correct B. (A) Double stranded RNA viruses C. Both A and B are correct D. (C) Minus strand RNA viruses E. (B) Plus strand RNA viruses
A
Which of the following is NOT a mechanism of viral DNA synthesis? A. All the mentioned processes are mechanisms of viral DNA synthesis B. Strand displacement DNA synthesis C. Replication fork formation at the origin of replication for DNA synthesis D. Rolling circle DNA synthesis
A
Which of the following is NOT true about a typical (e.g. Avian Leukosis Virus: ALV) retrovirus genome and its function? A. The (+) strand genome RNA is 5′ capped and 3′ polyadenylated and immediately translated into Gag and Gag-Pol polyprotein precursor immediately upon viral entry into the host cell B. Host tRNAs are packaged in the virion bound to the pbs (primer binding site) of the genome C. The retroviral genome is (+) strand RNA with two identical copies in each virion D. The viral genome is coated with nucleocapsid protein
A
Which of the following is incorrect regarding Adenovirus DNA replication? A. A pre-terminal protein (pTP) binds to DNA pol and the α phosphoryl group of a dGMP is bonded with a serine residue of the pTP; which acts as the primer for the DNA synthesis by bonding with the first dCMP on the template strand B.The DNA is replicated by strand displacement C. DNA synthesis by strand displacement and DNA binding protein (DBP) coated displaced strand DNA synthesis both simultaneously participate in Adenovirus DNA replication D. The displaced strand during DNA synthesis is coated with a DNA binding protein and circularized where the inverted terminal repeats (ITRs) base pair and a new strand synthesis can initiate with the help of pre-terminal protein (pTP) using the 3` end as the template
A
Which of the following is the most logical explanation behind the naming "reverse transcriptase" A. Because of the enzyme's ability to reverse the flow of the genetic information B. Because of the enzyme's ability to reverse the process of translation followed by transcription C. Because of the enzyme's ability to synthesize the RNA from the DNA in a reverse order using 5′end of the RNA as the initiation site D. All of the other statements are correct logics behind the naming
A
Which of the following is true about Hepadnavirus? A. Reverse transcription happens only in the core particle with partially assembled capsid B. All of the other statements are true about Hepadnavirus C. They contain circular DNA as their genome where one strand is complete, circular and covalently closed and the other strand is only about 2/3 complete D. The 5` end of the (-) strand DNA is attached to an RNA primer for reverse transcription E. The viral reverse transcriptase is attached to the 5′end of the (+) strand and immediately reverse transcribe the genome upon entry into the cytoplasm
A
Which of the following mode of repression is seen in the late phase genes of Simian Virus 40 (SV40)? A. Initiator Binding Protein (IBP) binding to an initiator sequence B. TFIID binding to TATA sequence C. Initiation complex binding to an initiator sequence D. RNA pol II binding to an initiator sequence
A
Which of the following process facilitates the second template exchange of hepadnavirus reverse transcription? A. A hairpin formation near the 3′ end of the DR1 sequence on the (−) strand DNA switches the RNA primer to the DR2 sequence near the 5′ end of the (−) strand DNA B. Conformational change of TP (terminal protein) and reverse transcriptase exchange the template from 5′ end to 3′ end of the pre-genomic RNA C. Template switching is initiated by the 5′ end limit product of the RNaseH digestion of the pre-genomic RNA D. RNase H digestion of the 3′ dr1 sequence and downstream secondary structure facilitates template switching in the pre-genomic RNA
A
Which of the following process may be responsible for the regulation of viral transcription through nucleosomal templates? A. All of the choices are correct B. Histone methylation C. Histone de-acetylation D. Histone acetylation
A
Which of the following process occurs, immediately after the release of a viral gapped DNA or viral plus-strand DNA? A. Repairment of double stranded DNA template for transcription B. Replication into double stranded RNA template for transcription C. Transcription into mRNA D. Replication into double stranded genomic DNA
A
Which of the following protein binds to the TATA sequence and regulate transcription A. TFIID B. TFIIA C. TFIIC D. TFIIB
A
Which of the following protein is NOT involved in viral DNA replication? A. All of the mentioned proteins are involved in viral DNA replication B. DNA dependent DNA polymerases C. Helicases D. Exonucleases E. Topoisomerases
A
Which of the following protein is involved in viral DNA replication? A. All of the above are involved in viral DNA replication B. Ribonucleotide reductase C. Thymidine kinase D. dUTPase
A
Which of the following sequence is the part of the "core promoter" sequence for RNA polymerase II? A. TATA sequence B. All of the choices constitute the "core promoter" C. Cis-acting local regulatory sequences D. Trans-acting local regulatory sequences
A
Which of the following steps occur during reverse transcription of retroviral genomic RNA? A. All of the mentioned events occur during reverse transcription B. Two template exchanges C. Priming of (−) DNA synthesis by tRNA D. Degradation of the viral RNA by RNase H E. Generation of two LTRs
A
Which signature structure of the tRNA is used as a reverse transcription primer, binding to pbs (primer binding site) in a typical (e.g. Avian Leukosis Virus: ALV) retroviral genome? A. The ΤψC loop and arm B. The D loop and arm C. The acceptor arm D. The anticodon loop arm and
A
Which of the following is NOT true about retroviral DNA integration into the host genome? A. Integrase makes a staggered nick (a single strand break slightly apart) on each strand of the host DNA B. Integrase removes two nucleotides from the 5` ends of each retroviral DNA strands C. All of the above/other are true about the retroviral DNA integration D. It is catalyzed by enzyme integrase Integrase is a tetramer
B
Adenovirus E1A protein stimulating the expression of adenovirus E2 protein which then stimulates the expression of adenovirus IVa2 & L4 protein is an example of: A. Dimerization B. Cascade regulation C. Repression of gene expression D. A negative autoregulatory loop
B
DNA viruses require DNA binding proteins for transcriptional control. Which of the following may be the source of these DNA binding proteins? A. Only the host cell B. Both virus and/or the host cell C. Only the virus D. None of the choices are correct
B
How are the Influenza virus and VSV RNA synthesis similar? A. The switch from mRNA to genome RNA synthesis is controlled by an RNA-binding protein ! B. All of the above C. Polyadenylation occurs at a short stretch of U residues D. Viral mRNAs are shorter than (−) genome RNA
B
Spliceosomes which of the following is found in a spliceosome? A. Silencing RNAs (siRNA) B. Small nuclear RNAs (snRNA) C. Ribosomal RNAs D. Micro RNAs (mi-RNA)
B
What is the first biosynthetic event that occurs in cells infected with dsDNA Viruses? A. Membrane fusion B. Transcription C. NA replication D. Protein synthesis
B
What is the function of the cellular DNA ligase IV/XRCC4 in Herpesvirus DNA replication? A. DNA ligase IV/XRCC4 is responsible sealing the gaps of the replicated DNA B. DNA ligase IV/XRCC4 is responsible for circularization of the viral DNA C. DNA ligase IV/XRCC4 is responsible for the terminal resolution ligation of the separated DNA strands D. DNA ligase IV/XRCC4 is responsible for end to end DNA ligation to form concatemers during rolling circle DNA synthesis
B
Which RNA polymerase mode of action "model" explains the VSV mRNA synthesis and attenuation at intergenic regions? a. Cap snatching model b. Stop-start model c. Protein dependent priming model d. Moving template model
B
Which of the following is NOT a universal rule of viral DNA replication? A. DNA synthesis may be primer dependent or independent B. Replication can initiate at random sites on templates called origin of replication C. The DNA synthesis is always template directed D. The dNTPs are incorporated at the 3'-OH of the DNA chain
B
Which of the following is NOT true about mRNA polyadenylation of DNA viruses? A. The polyadenylation occurs in the nucleus before export into the cytoplasm B. PolyA polymerase slips on a few U residues to incorporate about 200 A residues at the 3` end of the RNA C. PolyA polymerase is the enzyme responsible for the polyadenylation of the mRNAs D. The pre-mRNAs are cleaved at the prospective polyadenylation site for polyadenylation
B
Which of the following is NOT true about the second strand (+) strand DNA synthesis of a typical retroviral (e.g. Avian Leukosis Virus: ALV) reverse transcription? A. The second strand synthesis stops temporarily at the modified base of the tRNA attached to the first strand before template exchange B. The first template exchange synthesize the second DNA strand C. All of the other statements are true about the second strand (+ strand) DNA synthesis of a typical retroviral (e.g. Avian Leukosis Virus: ALV) reverse transcription D. A polypurine tract (ppp) from RNaseH terminal digestion product serves as the primer for the second strand synthesis
B
Which of the following is unique of a 5' cap structure of an mRNA? A. The adenine is bonded to the second base guanine by a 5-5` phosphate linkage B. None of the choices are correct C. The 2nd base of the cap is guanine, which is methylated at the 7th carbon (m7) D. Usually, the first capping base is adenine
B
Which of the following mechanism explains the abrogation of cellular Rb protein by viral proteins A. Viral protein like E1A binds to Rb and recruit histone deacetylases which lead to transcriptional activation B. Viral protein like E1A competitively binds to Rb protein which removes Rb protein bound to transcription factor E2f and Dp and Rb protein free E2f and Dp induce transcription C. Viral proteins like E1A competitively binds to Rb protein; which in turn binds to transcription factor E2F and Dp to form E1A, Rb, E2F, Dp complex which induce transcription D. Viral protein like E1A binds to Rb protein and induce phosphorylation which dissociate Rb from E2f and Dp protein leading to transcriptional activation
B
Which of the following process acts as the primary "switch" from Vesicular Stomatitis Virus (VSV) mRNA synthesis to genome RNA synthesis? A. Slippage of the RNA polymerase at the 3~ end of the genome RNA B. Encapsidation of the "leader RNA" by N protein and association of N protein with RNA polymerase which reads through the intergenic region C. SLippage of the RNA polymerase at the 5~ end of the genome RNA D. Production of a large amount of viral structural proteins in the cell helps the RNA dependent RNA polymerase to read through the intergenic region
B
Which of the following process describes the polyadenylation of mRNAs in Vesicular Stomatitis Virus (VSV)? A. Snatching of poly(A) tails from cellular mRNAs B. Slippage of the RNA polymerase and recopying over a seven residue uridine (U7) at each intergenic region C. Addition of poly(A) with the help of Poly(A) binding protein, PABP D. All of the above processes can polyadenylate VSV mRNAs
B
Which of the following process explains Adenoviral anti-repression of transcription by abrogation of Rb (Retinoblastoma protein)? A. E1A binds to Rb and prevents Rb Retinoblastoma protein) to be associated with E2F and Dp-1. In absence of Rb, no Hdacs (histone deacetylases) are recruited making the DNA tightly wrapped around the nucleosome, and transcription complex can be formed and proceed. B. E1A binds to Rb and prevents Rb Retinoblastoma protein) to be associated with E2F and Dp-1. In absence of Rb, no Hdacs (histone deacetylases) are recruited making the DNA loose and accessible around the nucleosome, and transcription complex can be formed and proceed. C. E2fbinds to Rb and prevents Rb Retinoblastoma protein) to be associated with E1A and Dp-1. In absence of Rb, no Hdacs (histone deacetylases) are recruited making the DNA loose and accessible around the nucleosome, and transcription complex can be formed and proceed. D. E2f binds to Rb and prevents Rb (Retinoblastoma protein) to be associated with E2F and Dp-1. In absence of Rb, no Hdacs (histone deacetylases) are recruited making the DNA loose and accessible around the nucleosome, and transcription complex can be formed and proceed.
B
Which of the following process form the 5` mRNA cap structure in the Influenza Virus? A. The 5`cap is cleaved and snatched by the virus from host small nuclear (sn) RNAs B. The 5`cap is cleaved and snatched by the virus from host nuclear pre-mRNAs C. The RNA polymerase catalyzes a 7-methyl guanosine formation followed by 5`-5` triphosphate bridge formation to the second adenine base D. The RNA polymerase snatches a 5` binding protein cap to cap the mRNA and attach two uridine residues
B
Which of the following protein complex is required for the synthesis of RNA primer during SV40 DNA replication? A. DNA pol I and the primase complex B. DNA polymerase α and the primase complex C. DNA polymerase δ and the primase complex D. DNA polymerase ε and the primase complex
B
Which of the following reaction takes place at the splicing site of a pre-mRNA? A. Cis-esterification B. Trans-esterification C. Acetylation D. Methylation
B
Which of the following region is the actual start site for mRNA transcription? A. Repressor sequence B. Initiator sequence C. Enhancer sequence D. TATA sequence
B
Which of the following statement about reverse transcriptase (RT) is NOT correct? A. RT is packaged in the retrovirus particle B. RT is unique to retroviruses C. The name of the enzyme comes from its ability to reverse the flow of genetic information D. Might have bridged the ancient RNA world and the DNA world The reverse transcriptase holoenzyme also has RNase H activity
B
Which of the following statement is NOT correct about a typical (e.g. Avian Leukosis Virus: ALV) retrovirus? A. The one strand of genomic RNA, Gag-pol-env mRNA and the unspliced pre-mRNA are the all the same B. The unspliced env pre-mRNA codes SU (surface) and TM (transmembrane) proteins C. The pol region of the retroviral genome code for reverse transcriptase and integrase D. Protease processing/cleaving of the Gag precursor protein forms several viral proteins E. All of the other statements are correct about the typical (e.g. Avian Leukosis Virus: ALV) retrovirus
B
Which of the following statement is NOT correct about reverse transcriptase (RT)? A. RT might be the bridge between the RNA and the DNA world B. Every virus that codes reverse transcriptase must have integrase to integrate the reverse transcribed DNA into host DNA C. Prokaryotes, Archaea and Eukaryotes all have RT D. RT was present in our common ancestor before the evolution and separation of the of Prokaryotes, Archaea and Eukaryotes
B
Which of the following statement is true about retroviral transformation? A. The retroviruses cause permanent changes in cells B. All of the other statements are true about retroviral transformation. C. Become permanent part of the host DNA D. The integrated retoviral genome is called a "provirus" E. Retroviral DNA is integrated into host genome
B
Which statement about polyadenylation of DNA virus mRNAs is correct? A. Is specified by a stretch of U residues in the template B. It occurs after cleavage of pre-mRNA C. It always occurs in the cytoplasm D. Poly(A) is added at the 5'-end of pre-mRNA
B
Which statement about viral DNA synthesis is NOT correct? A. Large DNA viruses encode many proteins involved in DNA synthesis B. Some viruses encode all proteins needed for DNA replication C. Small DNA viruses encode at least one protein involved in DNA synthesis D. Viral DNA replication is always delayed after infection because it requires the synthesis of at least one viral protein
B
Which statement about viral DNA synthesis is correct? A. Small DNA viruses do not encode any protein involved in DNA synthesis B. Large DNA viruses encode many proteins involved in DNA synthesis C. Viral DNA replication begins as soon as the genomic DNA is delivered into the nucleus D. Some viruses encode all proteins needed for DNA replication
B
"Endogenization" is a term used to define which of the following statement? A. Integration of the proviral DNA into the host chromosomes B. Excision of the proviral DNA from the host germ cell DNA and passage onto the autosomes C. Integration of the proviral DNA in host germline and passage onto the next progeny D. Movement and reintegration of proviral and retrotransposons in host by reverse transcriptase
C
Actinomycin D was utilized in the experiments that lead to the discovery of the viral RNA polymerase. What was the principle of the experiment? A. In the presence of dNTP and Actinomycin D; which inhibited cellular DNA dependent RNA polymerase; RNA synthesis occurred in the virally infected cell extract. B.In the presence of dNTP and Actinomycin D; which inhibited cellular DNA dependent RNA polymerase; RNA synthesis occurred in the virally infected cell extract. C. In the presence of NTP and Actinomycin D; which inhibited cellular DNA-dependent RNA polymerase; RNA synthesis occurred in the virally infected cell extract. D. In the presence of NTP and Actinomycin D; which inhibited cellular RNA dependent RNA polymerase; RNA synthesis occurred in the virally infected cell extract.
C
Coronavirus and Retrovirus are two unique viruses among the plus-strand RNA viruses. Which of the following feature make them unique? A. Both A and B are correct B. Both of them carry reverse transcriptase C. They are the only plus-strand RNA viruses with encapsidated genomic RNA in the form of the nucleocapsid D. They are the only enveloped viruses among plus-strand RNA viruses
C
How many mRNA start sites may be present in an "initiator sequence" among DNA viruses? A. 1 or 3 B. Always one C. 1 or multiple D. Always 3
C
How the "immediate early" transcriptional regulation of Herpesvirus is different from the Adenovirus? A. The Herpesvirus "immediate early" transcription factor VP16 have cellular origin whereas adenovirus packs the "immediate early" E1A transcription factor in the virion B. Herpesvirus uses a cascade regulation unlike Adenoviral autoregulation C. The "immediate early" transcription factor VP16 is packaged into the Herpesvirus virion but Adenovirus use cellular transcription factors for its "immediate early" transcription D. Herpesvirus packs its RNA polymerase but Adenovirus do not
C
Reverse transcriptase is an enzyme with low fidelity and low processivity. Which of the following statement best suites the above definition? A. The enzyme is always capable of incorporating correct nucleotides at a very high rate of synthesis for a productive viral infection B. The enzyme incorporates always correct nucleotides but in doing so the synthesis rate is also slow C. The enzyme often incorporates wrong nucleotides and its synthesis rate is slow as well D. The enzyme often incorporates wrong nucleotides as its synthesis rate is very fast
C
The HIV-1 reverse transcriptase contains p66 protein and p51 proteins and each contain the thumb, palm and finger domain. Which is the most logical way to describe the enzyme? A. It is homodimeric protein B. It is homotrimeric protein C. It is heterodimeric protein D. It is heterotrimeric protein
C
The SU (surface protein) and TM (Transmembrane protein) are coded by which region of a typical (e.g. Avian Leukosis Virus: ALV) retroviral genome? A. gag B. LTR C. env D. Pol
C
The SV40 genome is a circular dsDNA. Which statement about its replication is correct? A. Replication is bidirectional from a single ori B. Has leading and lagging strand synthesis C. All of the above D. Viral Large T (LT) antigen protein binds and unwinds the ori
C
The reverse transcriptase enzyme is coded by which region of a typical (e.g. Avian Leukosis Virus; ALV) retroviral genome? A. gag B. LTR C. pol D. Env
C
The transcription of MOST but not all DNA viruses are carried out by which of the following enzyme? A. DNA pol III B. RNA pol III C. RNA pol II D. DNA pol I
C
Which mode of transcriptional regulation is displayed; when transcription and translation of gene X result in the formation of protein X and protein X turn on the transcription of gene Y. A. Positive feedback B. Negative autoregulatory loop C. Cascade regulation D. Positive autoregulatory loop
C
Which of the following feature is NOT observed in DNA dependent DNA polymerases? A. Di-valent metal ions coordinate the incoming nucleotide to catalyze the reaction B. They contain the thumb, palm and the finger domain C. The thumb domain act as the catalytic site D. Have conserved GDD or close amino acid motifs at the catalytic site
C
Which of the following feature is NOT observed in SV40 Large T (LT) antigen protein? A. Contain replication origin binding domain B. Contain a helicase domain which unwinds DNA in association with other proteins C. Contains DNA Pol α-Primase domain which synthesizes RNA primers D. Contain an ATPase domain
C
Which of the following is NOT a function of the Large T (LT) antigen protein in SV40 DNA replication A. LT protein shows intrinsic 3' to 5' helicase activity and unwinds the SV40 DNA in an ATP dependent manner and Rp-A binds onto the separated single strands and Topoisomerases keep the unwound DNA relaxed B. Two LT protein hexamers bind on the opposite end of the SV40 origin of replication C. LT protein in association with DNA Pol α unwinds SV40 DNA in a 5' to 3' direction in an ATP dependent manner and Rp-A binds onto the separated single strands and Topoisomerases keep the unwound DNA relaxed D. In presence of ATP, LT forms hexamer and binds to the SV40 origin of replication and undergo conformational changes to denature the DNA strands
C
Which of the following is incorrect about the poxvirus DNA genome and its replication A. Poxvirus DNA is a double stranded DNA with covalently joined ends B. The ends of the poxvirus DNA contain inverted terminal repeats (ITRs) C. All the viral replication proteins are synthesized by the virus D. Viral replication occurs in the cytoplasm of the cell
C
Which of the following is the signature structure of a DNA binding domain of a transcriptional activator protein? A. Dimerization domain B. Leucine zipper! C. Zinc finger D. Cloverleaf structure
C
Which of the following is true about the splicing of viral Pre-mRNAs? A. Alternative splicing can produce multiple proteins from the same Pre-mRNA B. Splicing is necessary for the binding and activation of the nuclear export proteins for most viral mRNA export into the cytoplasm from the nucleus C. All of the above are true about viral mRNA splicing D. Some retroviral RNA is exported "unspliced" out of the nucleus facilitated by special nuclear export binding proteins
C
Which of the following might be the most probable cause of resistance of retroviruses against UV and ionizing radiation? A. Reverse transcription is error prone and likely repair the mutation caused by UV and ionizing radiation; a mechanism not seen in any other viruses B. As the provirus is integrated in the host genome UV and ionizing radiation does not have any effect on the retroviruses C. Copy choice in between two RNA copies of the diploid genome is likely to build an error free functional genome; even if one of the gene is mutated due to UV and ionizing radiation D. Retroviruses use cellular RNA pol II to make mRNAs and proteins from the integrated provirus; which is resistant to UV and ionizing radiation
C
Which of the following non-retro-viral DNA replication does not require an RNA primer? A. Rolling circle DNA synthesis B. Replication fork based DNA synthesis from a single origin C. Strand displacement DNA synthesis D. Replication fork based DNA synthesis from a multiple origins
C
Which of the following acts as a primer for the initiation of poliovirus mRNA synthesis? A. The VPg protein B. The CRE element and covalently bonded two uridine residues C. The 3` pseudoknot D. The VPg protein and covalently bonded two uridine residues
D
Which of the following protein is produced in Simian Virus 40 (SV40) in the early phase of transcription and regulate DNA replication and expression of late genes? A. E2 B. Small T antigen (ST) C. Large T antigen (LT) D. E1A
C
Which statement about viral DNA synthesis is correct? A. Some viruses encode all proteins needed for DNA replication B. Viral DNA replication begins as soon as the genomic DNA is delivered into the nucleus C. Large DNA viruses encode many proteins involved in DNA synthesis D. Small DNA viruses do not encode any protein involved in DNA synthesis
C
Which of the following enzyme/s has/have conserved GDD (or significantly close) amino acid motifs at their catalytic site? A. RNA dependent DNA polymerase B. DNA dependent DNA polymerase C. RNA dependent RNA polymerase D. All of the above enzymes have conserved GDD (or significantly close) amino acid motifs E. DNA dependent RNA polymerase
D
Which of the following group of viruses ALWAYS contain an encapsidated RNA in the form of nucleocapsid? a. All of the RNA viruses have encapsidated RNA in the form of the nucleocapsid b. Double-stranded RNA viruses c. Plus strand RNA viruses d. Minus strand RNA viruses
D
Which of the following group of viruses does NOT have naked RNA in the virus particle? A. Double-stranded RNA viruses B. Plus stranded RNA viruses C. None of the group of viruses above has naked RNA in the virus particle D. Minus strand RNA viruses
D
During SV40 DNA replication, the supercoiling of the dsDNA is inevitable. Which of the following statement correctly illustrates the different mechanisms of supercoiling removal during replication and after replication (terminal resolution)? A. During replication both single and double strand nicks are responsible for supercoil relaxation whereas only double strand nicks are responsible for supercoil relaxation (terminal resolution) at the end of DNA replication B. During replication Topoisomerase I and after replication Topoisomerase II carry out relaxation of the supercoils C. During replication Topoisomerase II and after replication Topoisomerase I and II both carry out relaxation of the supercoils D. During replication single strand nicks are responsible for supercoil relaxation whereas double strand nicks are responsible for supercoil relaxation (terminal resolution) at the end of DNA replication
D
How many di-valent metal ion binding sites are present in reverse transcriptase holoenzyme? A. 1 B. 2 C. 3 D. 4
D
Poxviruses and giant viruses never have to deliver their DNA into the nucleus. Which of the following would justify such a phenomenon? A. Pox and giant viruses have all the mRNAs packaged within the virion B. Pox and giant viruses have all the DNA replication machinery packaged within the virion C. Pox and giant viruses have all the translational machinery packaged within the virion D. Pox and giant viruses have all the transcription machinery packaged within the virion
D
The mRNAs are synthesized by the Reovirus in which of the following structural state of the virus? A. After the genomic RNAs are released into the cytoplasm from the core B. Double capsid virion stage of the virus after in the acidic endosome C. At the Infectious Sub Viral Particle (ISVP) stage after acid-dependent proteolytic cleavage ! D. When the core particle is released into the cytoplasm
D
What makes poxvirus DNA replication different from all of the other viruses? A. DNA synthesis occurs by strand displacement B. DNA synthesis occurs in the nucleus C. The complete replication machinery is encoded by the viral genome D. None of the above
D
What strategy is used by the Poliovirus to make many proteins from a single mRNA? A. Alternative splicing B. Alternative translational stop C. Alternative translational start D. Proteolytic cleavage of the polyprotein
D
Which is a part of the Poliovirus replication strategy? A. De novo (without primer) initiation of RNA synthesis B. The production of subgenomic mRNAs C. All of the above D. Circularization of template for initiation of RNA synthesis
D
Which of the following group of viruses usually do NOT pack RNA dependent RNA polymerase in the virus particle? A. Minus strand RNA viruses B. Double-stranded RNA viruses C. All of the above pack RNA dependent RNA polymerase in the virus particle D. Plus strand RNA viruses
D
Which of the following is NOT a viral origin binding protein? A. Parvovirus Rep 78/68 protein B. Adenovirus pre-terminal protein (pTP) C. Polyomavirus (SV40) Large T (LT) antigen protein D. Herpesvirus proliferative cell nuclear antigen (Pcna) protein
D
Which of the following is NOT true about retrotransposons A. They are likely progenitor of retroviruses B. All of the other statements are true about retrotransposons C. They contain retroviral gag pol sequences and code reverse transcriptase D. They can be present as LINEs (Long Interspersed Nuclear Elements) or SINEs (Short Interspersed Nuclear Elements) E. They are mobile elements of the genome
D
Which of the following is NOT true about the Long Terminal Repeat (LTR) in a retrovirus; such as HIV-1? A. The LTRs are essential for integration into the host genome B. The LTRs have strong promoters C. The LTRs have signature U3, R and U5 regions flanked by pbs (primer binding site) and ppt (poly purine tract) D. The LTRs are found on both the 5` and 3` end of the diploid retroviral genome (+) RNA genome
D
Which of the following is incorrect about Parvovirus DNA synthesis? A. DNA synthesis is by strand displacement B. DNA replication requires DNA pol δ, Rf-C and PCNA C. Replication is continuous D. Rep78/68 proteins are required for RNA primer synthesis, initiation, and resolution
D
Which of the following is unique in Reovirus RNA dependent RNA synthesis? A. The mRNAs are produced inside the viral core particle and never synthesized in the cytoplasm B. One of each of the 10 segments of double-stranded genomic RNA is associated with a viral RNA dependent RNA polymerase and is located under each "turret proteins" in each fivefold axis which synthesizes the mRNA C. The RNA dependent RNA polymerase is located inside the viral core below the turret proteins which synthesize the mRNAs D. All of the above are unique in Reovirus RNA dependent RNA synthesis
D
Which of the following method is used by the Influenza virus to synthesize its mRNAs? A. 3′ co-priming and nested mRNA synthesis model B. Stop start model C. In-particle mRNA synthesis model D. Moving template model
D
Which of the following process is involved in the regulation of viral DNA synthesis? A. Virally encoded early gene products often induce quiescent cells to enter the cell cycle again into the synthesis (S) phase B. Host replication proteins are induced by early viral gene products C. Viruses must recruit host replication proteins to preferentially synthesize viral DNA D. All of the mentioned processes are involved in the regulation of viral DNA synthesis
D
Which of the following protein/protein-complex is NOT associated with priming of DNA synthesis? A. SV40: DNA pol α - primase complex B. Herpesvirus: UL5, 8 and 53-primase C. Adenovirus: pre-terminal protein (pTP) D. Parvovirus: Rep78/68 protein
D
Which of the following statement is true about Adenoviral transcriptional regulation? A. DNA replication exhibit anti-repression by relief of promoter occlusion B. E1A produced in the immediate-early phase enhance early phase gene transcription C. E2 produced in early phase enhance DNA replication D. All of the other choices are true true
D
Which of the following statement is NOT true about the regulation of retroviral DNA integration? A. Integrase bound to chromatinized retroviral RNA interacts with Capsid (CA) and LEDGF protein along with associated CPSF6 and RNA pol II and integrates in a region close to a transcriptionally active region B. Integrase function is regulated by host as well as the viral Capsid (CA) protein C. The BAF protein prevents auto-integration of the retroviral DNA D. Preferential integration towards DNA sequences that are wrapped around nucleosomes E. All of the above/other are true about retroviral DNA integration
E
Which of the following statements about retroelements is NOT correct? A. They are currently entering the Koala germline in south-eastern Australia B. None of the above/other C. They can be beneficial D. There are many retroelement copies in eukaryotic genomes E. Retroelements in the human genome sometimes may be fully transcribed to produce infectious viruses
E
Which of the following is the major difference between the Vesicular Stomatitis Virus (VSV) and Influenza Virus mRNA synthesis? a.VSV mRNA synthesis is carried out by viral RNA dependent RNA polymerase; in contrast, the Influenza virus steals/snatches the DNA dependent RNA polymerase from the nucleus of the host cell b.VSV mRNAs are synthesized in the cytoplasm whereas the Influenza virus mRNAs are synthesized in the nucleus. c.All of the other are major differences between Vesicular Stomatitis Virus (VSV) and Influenza Virus mRNA synthesis d. VSV produce one genome length mRNA whereas Influenza Virus always subgenomic mRNAs from all of its individual segments
b
Which of the following type of metal ion coordinate the incoming nucleotide in a polymerization reaction catalyzed by polynucleotide polymerase class of enzymes like RNA or DNA polymerases? a.Tetra-valent metal ion b.Di-valent metal ion c.Tri-valent metal ion d.Mono-valent metal ion
b
Which of the following attributes to the specificity of RNA polymerases towards NTPs over dNTPs? a. The UTP b. The 2` hydroxyl of the deoxy-ribose sugar c. The 2` hydroxyl of the ribose sugar d. The 2` hydrogen of the ribose sugar
c
Which of the following enzyme/s has/have conserved GDD (or significantly close) amino acid motifs at their catalytic site? a.DNA dependent RNA polymerase nwered b.RNA dependent RNA polymerase c.All of the above enzymes have conserved GDD (or significantly close) amino acid motifs d. DNA dependent DNA polymerase RNA dependent DNA polymerase
c
Which of the following is NOT true about viral mRNAs? a. Viral mRNAs could be genome length or shorter sub-genomic length b. All of the above are true about the viral mRNAs c. Uncapped viral mRNAs can't be translated into protein by the ribosomes d. Viral mRNAs may be attached with a protein at its 5` end; instead of a cap
c
Which of the following strategy is observed in the Coronavirus reproductive events? a. the genomic RNA is synthesized on a (-) sense template where the viral RdRp do not jump from any of the translational regulatory sequences (TRS) making a long (+) sense genomic RNA without any loss of nucleotides b. mRNAs are synthesized on (-) sense templates that use a 3' co priming followed by a variable-length nested RNA synthesis and addition of the 5' leader sequence c. Only the first open reading frame (ORF) is translated into the corresponding proteins in all subgenomic mRNAs of the coronavirus d. All of the other events are observed in the coronavirus reproductive cycle e. Two long polyproteins are translated by the ribosome by ribosomal frame shifting
d