Virology Quiz
Virology –Midterm vA, 22 April 2013:
1. Which of the following genomic nucleic acids are only found in viruses? a. dsDNA b. dsRNA c. ssDNA d. ssRNA e. B, C and D 2. About what percent of the human genome is indisputably viral? a. 1 b. 2 c. 5 d. 10 e. 50 3. Viruses were first discovered (and named as such) because they : a. could not be grown b. were very small c. were alive d. ate bacteria e. C and D 4. Phage therapy is to : a. Use a virus to kill a virus b. Use viruses to kill cancer cells c. Use viruses to kill bacteria d. Perform gene therapy e. Eat probiotics 5. What is probably the main reason to NOT use animals for determining virus counts: a. Mice are cute b. High Cost c. Reproducibility d. Study pathogenesis e. Fast 6. Incubation is …show more content…
critical in a plaque assay because: a. Viruses must bind to host cells b. Viruses must release their genome c. Viruses must undergo one round of replication d. Viruses must undergo many rounds of replication e. The host cells must be able to move 7. If you have 10 plaques on a plate after plating 1ml of a 10-7 dilution in a plaque assay your original virus titer is : a. 10-6 PFU/ml b. 106 PFU/ml c. 10-7 PFU/ml d. 107 PFU/ml e. 108 PFU/ml 8. Which of the following is a major drawback of the hemagglutination assay? a. It is slow b. It is expensive c. It is not quantitative 9.
Key VERSION (A)
d. It says nothing about virus infectivity e. It is very hard to perform In order to determine what percentage of cells in a population are infected by 1 and only 1 virus, you need to know a. The PFU b. How many viruses you have c. How many cells you have d. The gaussian distribution e. B and C The host range of viruses is also known as : a. Hemagglutination b. Tropism c. Virion binding d. Decapsidation e. Virion uncoating How many different classes of viruses are there according to Baltimore? a. 1 b. 2 c. 4 d. 6 e. 8 Which kinds of viruses need genome replication before translation can take place? a. Plus strand RNA viruses b. Negative strand RNA viruses c. Double stranded DNA viruses d. Double stranded RNA viruses e. All but B Which of the following techniques for virus structure determination has the highest resolution: a. Negative stain b. Thin section c. Cryo-electron microscopy d. X-ray crystallography e. A and B The simplest of icosahedrally symmetric viruses have capsid proteins with __ different amino acid sequence(s) in the virion. a. 1 b. 3 c. 20 d. 60 e. 180 A virus with icosahedral quasisymmetry with an “h” of 2 and “k” of 0 has how many coat proteins in its capsid? a. 60 b. 120 c. 180 d. 240 e. 300
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16. Polio said to have pT3 symmetry because a. it has 60 subunits in the structure b. the coat protein has a beta barrel fold c. It has 3 different major coat proteins d. It encapsidates positive strand RNA e. It is not icosahedrally symmetric 17. The capsids of the largest known viruses seem to have : a. Helical symmetry b. Iscosahedral symmetry c. Appears to be derived from icosahedral symmetry d. Appears to be derived from heilcal symmetry e. Apparently no symmetry 18. The majority of the amino acids of most virus envelope proteins in mature enveloped virions is : a. Outside the envelope b. In the envelope membrane c. Inside the envelope d. Composed of lysines and arginines e. Composed of glutamates and aspartates 19. Which of the following amino acids are likely to be present in fusion peptides? a. Lysine and arginine b. Glutamate and Aspartate c. Glutamine and Asparagine d. Cysteine and Methionine e. Leucine, isoleucine and valine 20. What happens to influenza hemagglutinin HA0 to become HA1 and HA2? a. It binds to sialic acid b. It becomes trimeric c. It is proteolyzed d. It has a large conformational change e. It is translated 21. RNA viruses mostly replicate in the nucleus because a. Precursors are available b. The replicases are there c. Translation takes place in the nucleus d. The RNA is transported through the nuclear pore e. The pH is lower in the nucleus 22. Virus “receptors” are generally : a. Only used by viruses b. Used by viruses and cellular processes c. Sialic-acid containing d. Trimeric e. Composed of multiple proteins
23. Most eukaryotic viruses use which one of the following processes to cross the plasma membrane? a. Receptor mediated endocytosis b. pinocytosis c. phagocytosis d. Injection of genome across the membrane e. Integrin-mediated membrane fusion 24. What is the mechanism that causes membrane fusion? a. Proteolysis b. Insertion of fusion peptide into host membrane c. Conformational change of fusion protein before fusion peptide insertion d. Conformational change of fusion protein after fusion peptide insertion e. Endocytosis 25. What aspect of attachment and entry by bacteriophage T4 is fundamentally different than those of animal viruses whose attachment and entry videos we watched? a. Receptor interaction b. Conformational change of receptor-binding proteins c. Genome entry d. A and B e. A, B and C 26. What aspect of viral replication is blocked by the effects of vaccination? a. Receptor binding b. Virion uncoating c. Transport to nucleus d. Genome release e. Genome replication 27. Virus exit from the cell by enveloped viruses a. Must be very carefully timed b. Does not have to be carefully timed c. Often causes cell lysis d. A and C e. B and C 28. The role of PKR in defense against RNA virus infection is a. Blocking the cell cycle b. Stimulating apoptosis c. Stimulating interferon production d. Blocking translation e. C and D 29. CRISPRs were first thought to be a. A restriction system b. Similar to RNA interference c. Involved in blocking the cell cycle d. Blocking translation e. C and D
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RNA phage are used for determination of sewage contamination because : a. they infect E.coli b. there are a lot of them in sewage c. they are simple d. they have T=3 symmetry e. they replicate rapidly 31. How many proteins are encoded by a “typical” ssRNA bacteriophage (e.g. MS2)? a. 2 b. 4 c. 6 d. 8 e. >8 32. What is the receptor binding protein for MS2? a. The capsid protein b. The lysis protein c. The maturation protein d. The replicase e. A and B 33. What determines the relative amounts of proteins produced by MS2? a. How many copies of the genome are available b. The secondary structure of the RNA c. Speed of translation d. Speed of replication e. Amounts of cellular translation factors 34. Which protein is made first in (ssRNA phage) MS2? a. Maturation protein b. Lysis protein c. Readthrough protein d. Coat protein e. Replicase protein 35. Translation of the lysis protein in MS2 is due to lack of a. Replicase protein binding the genome b. Coat protein binding the genome c. Ribosome dissociation d. Ribosome assembly e. Secondary structure in the RNA 36. Formation of the negative strand of the MS2 genome depends on : a. Host transcription proteins b. Host replication proteins c. Host translation proteins d. Virus translation proteins e. Virus transcription proteins 37. The PhiX174 genome thought to be a message from outer space because : a. it had overlapping open reading frames b. it was single stranded c. transcription was tightly regulated d. it contained unusual …show more content…
codons e. it contained unique nucleotides
38. Why is it thought that the F,G, and H genes in PhiX174 do not overlap with other genes? a. Non-structural proteins cannot tolerate mutation b. Non-structural proteins can tolerate mutation c. Structural proteins cannot tolerate mutation d. Structural proteins can tolerate mutation e. Because they are the message from extraterrestrials 39. PhiX174 has T=1 icosahedral symmetry but has 180 structural protein subunits in the virion. Why? a. It is a pseudo T=1 structure b. This is true for all T=1 structures c. Only 1 protein is arranged with icosahedral symmetry d. Proteolysis takes place e. It is made as a provirus 40. What is most important for initiation of ds DNA (RF) replication in PhiX174? a. Secondary structure in the ssDNA b. The activity of the A protein c. That the genome is single stranded d. Helicase activity e. Host DNA polymerase III 41. In the absence of the B protein in PhiX174 you would expect many: a. empty procapsids b. monomeric proteins c. full procapsids but no virions d. pentameric subunits assemblies e. Free (unbound) copies of the genome 42. The microvirus genomes found in Boiling Springs Lake are most similar to a. PhiX174 b. Gokushoviruses c. Other microviruses from environmental samples d. Qbeta e. T7 43. Gene regulation in bacteriophage T7 is determined by : a. Translational initiation b. Transcriptional initiation c. Translational frameshifting d. Transcriptional termination e. Secondary structures 44. The T7 RNA polymerase is unique relative to other DNA-dependent RNA polymerases in : a. The promoter sequences that it recognizes b. The number of subunits in the enzyme c. The speed that it transcribes d. All of the above e. None of the above
45.
Early genes in most viruses are involved in : a. Regulating host functions b. Making RNA polymerases c. Replicating the virus genome d. Virus assembly e. Virus release 46. Genome entry for bacteriophage T7 is due to : a. Transcription by host enzymes b. Transcription by viral enzymes c. Injection d. Pilus retraction e. A and B 47. Why is the initial amount of DNA injected into a host cell on infection by bacteriophage T7 so short? a. So that the host RNA polymerase can bind its promoters b. So that the viral DNA is not degraded by host endonucleases c. So that the viral DNA is not degraded by viral endonucleases d. Because the DNA in the virion is not tightly packed e. So that the viral RNA polymerase can be made 48. Why is it thought that T7 lysozyme inhibits T7 RNA polymerase activity? a. Because T7 RNAP is too fast b. Because the genome is already in the cell c. Because T7 RNAP activity is not required late in infection d. To allow the holin protein to be made e. To serve as a scaffold for virion assembly 49. T7 DNA replication resembles host replication except : a. The requirement for a helicase b. That there is only one replication fork c. That it is “rolling circle” d. That single strands are made e. For the proteins involved 50. Most modern plasmid vectors contain : a. PhiX174 origins of replication b. Podovirus RNA polymerase promoters c. T7 DNA polymerase origins d. T7 holin genes e. All of the
above
1. Which of the following genomic nucleic acids are only found in viruses? a. dsDNA b. dsRNA c. ssDNA d. ssRNA e. B, C and D 2. About what percent of the human genome is indisputably viral? a. 1 b. 2 c. 5 d. 10 e. 50 3. Viruses were first discovered (and named as such) because they : a. could not be grown b. were very small c. were alive d. ate bacteria e. C and D 4. Phage therapy is to : a. Use a virus to kill a virus b. Use viruses to kill cancer cells c. Use viruses to kill bacteria d. Perform gene therapy e. Eat probiotics 5. What is probably the main reason to NOT use animals for determining virus counts: a. Mice are cute b. High Cost c. Reproducibility d. Study pathogenesis e. Fast 6. Incubation is …show more content…
critical in a plaque assay because: a. Viruses must bind to host cells b. Viruses must release their genome c. Viruses must undergo one round of replication d. Viruses must undergo many rounds of replication e. The host cells must be able to move 7. If you have 10 plaques on a plate after plating 1ml of a 10-7 dilution in a plaque assay your original virus titer is : a. 10-6 PFU/ml b. 106 PFU/ml c. 10-7 PFU/ml d. 107 PFU/ml e. 108 PFU/ml 8. Which of the following is a major drawback of the hemagglutination assay? a. It is slow b. It is expensive c. It is not quantitative 9.
Key VERSION (A)
d. It says nothing about virus infectivity e. It is very hard to perform In order to determine what percentage of cells in a population are infected by 1 and only 1 virus, you need to know a. The PFU b. How many viruses you have c. How many cells you have d. The gaussian distribution e. B and C The host range of viruses is also known as : a. Hemagglutination b. Tropism c. Virion binding d. Decapsidation e. Virion uncoating How many different classes of viruses are there according to Baltimore? a. 1 b. 2 c. 4 d. 6 e. 8 Which kinds of viruses need genome replication before translation can take place? a. Plus strand RNA viruses b. Negative strand RNA viruses c. Double stranded DNA viruses d. Double stranded RNA viruses e. All but B Which of the following techniques for virus structure determination has the highest resolution: a. Negative stain b. Thin section c. Cryo-electron microscopy d. X-ray crystallography e. A and B The simplest of icosahedrally symmetric viruses have capsid proteins with __ different amino acid sequence(s) in the virion. a. 1 b. 3 c. 20 d. 60 e. 180 A virus with icosahedral quasisymmetry with an “h” of 2 and “k” of 0 has how many coat proteins in its capsid? a. 60 b. 120 c. 180 d. 240 e. 300
10.
11.
12.
13.
14.
15.
16. Polio said to have pT3 symmetry because a. it has 60 subunits in the structure b. the coat protein has a beta barrel fold c. It has 3 different major coat proteins d. It encapsidates positive strand RNA e. It is not icosahedrally symmetric 17. The capsids of the largest known viruses seem to have : a. Helical symmetry b. Iscosahedral symmetry c. Appears to be derived from icosahedral symmetry d. Appears to be derived from heilcal symmetry e. Apparently no symmetry 18. The majority of the amino acids of most virus envelope proteins in mature enveloped virions is : a. Outside the envelope b. In the envelope membrane c. Inside the envelope d. Composed of lysines and arginines e. Composed of glutamates and aspartates 19. Which of the following amino acids are likely to be present in fusion peptides? a. Lysine and arginine b. Glutamate and Aspartate c. Glutamine and Asparagine d. Cysteine and Methionine e. Leucine, isoleucine and valine 20. What happens to influenza hemagglutinin HA0 to become HA1 and HA2? a. It binds to sialic acid b. It becomes trimeric c. It is proteolyzed d. It has a large conformational change e. It is translated 21. RNA viruses mostly replicate in the nucleus because a. Precursors are available b. The replicases are there c. Translation takes place in the nucleus d. The RNA is transported through the nuclear pore e. The pH is lower in the nucleus 22. Virus “receptors” are generally : a. Only used by viruses b. Used by viruses and cellular processes c. Sialic-acid containing d. Trimeric e. Composed of multiple proteins
23. Most eukaryotic viruses use which one of the following processes to cross the plasma membrane? a. Receptor mediated endocytosis b. pinocytosis c. phagocytosis d. Injection of genome across the membrane e. Integrin-mediated membrane fusion 24. What is the mechanism that causes membrane fusion? a. Proteolysis b. Insertion of fusion peptide into host membrane c. Conformational change of fusion protein before fusion peptide insertion d. Conformational change of fusion protein after fusion peptide insertion e. Endocytosis 25. What aspect of attachment and entry by bacteriophage T4 is fundamentally different than those of animal viruses whose attachment and entry videos we watched? a. Receptor interaction b. Conformational change of receptor-binding proteins c. Genome entry d. A and B e. A, B and C 26. What aspect of viral replication is blocked by the effects of vaccination? a. Receptor binding b. Virion uncoating c. Transport to nucleus d. Genome release e. Genome replication 27. Virus exit from the cell by enveloped viruses a. Must be very carefully timed b. Does not have to be carefully timed c. Often causes cell lysis d. A and C e. B and C 28. The role of PKR in defense against RNA virus infection is a. Blocking the cell cycle b. Stimulating apoptosis c. Stimulating interferon production d. Blocking translation e. C and D 29. CRISPRs were first thought to be a. A restriction system b. Similar to RNA interference c. Involved in blocking the cell cycle d. Blocking translation e. C and D
30.
RNA phage are used for determination of sewage contamination because : a. they infect E.coli b. there are a lot of them in sewage c. they are simple d. they have T=3 symmetry e. they replicate rapidly 31. How many proteins are encoded by a “typical” ssRNA bacteriophage (e.g. MS2)? a. 2 b. 4 c. 6 d. 8 e. >8 32. What is the receptor binding protein for MS2? a. The capsid protein b. The lysis protein c. The maturation protein d. The replicase e. A and B 33. What determines the relative amounts of proteins produced by MS2? a. How many copies of the genome are available b. The secondary structure of the RNA c. Speed of translation d. Speed of replication e. Amounts of cellular translation factors 34. Which protein is made first in (ssRNA phage) MS2? a. Maturation protein b. Lysis protein c. Readthrough protein d. Coat protein e. Replicase protein 35. Translation of the lysis protein in MS2 is due to lack of a. Replicase protein binding the genome b. Coat protein binding the genome c. Ribosome dissociation d. Ribosome assembly e. Secondary structure in the RNA 36. Formation of the negative strand of the MS2 genome depends on : a. Host transcription proteins b. Host replication proteins c. Host translation proteins d. Virus translation proteins e. Virus transcription proteins 37. The PhiX174 genome thought to be a message from outer space because : a. it had overlapping open reading frames b. it was single stranded c. transcription was tightly regulated d. it contained unusual …show more content…
codons e. it contained unique nucleotides
38. Why is it thought that the F,G, and H genes in PhiX174 do not overlap with other genes? a. Non-structural proteins cannot tolerate mutation b. Non-structural proteins can tolerate mutation c. Structural proteins cannot tolerate mutation d. Structural proteins can tolerate mutation e. Because they are the message from extraterrestrials 39. PhiX174 has T=1 icosahedral symmetry but has 180 structural protein subunits in the virion. Why? a. It is a pseudo T=1 structure b. This is true for all T=1 structures c. Only 1 protein is arranged with icosahedral symmetry d. Proteolysis takes place e. It is made as a provirus 40. What is most important for initiation of ds DNA (RF) replication in PhiX174? a. Secondary structure in the ssDNA b. The activity of the A protein c. That the genome is single stranded d. Helicase activity e. Host DNA polymerase III 41. In the absence of the B protein in PhiX174 you would expect many: a. empty procapsids b. monomeric proteins c. full procapsids but no virions d. pentameric subunits assemblies e. Free (unbound) copies of the genome 42. The microvirus genomes found in Boiling Springs Lake are most similar to a. PhiX174 b. Gokushoviruses c. Other microviruses from environmental samples d. Qbeta e. T7 43. Gene regulation in bacteriophage T7 is determined by : a. Translational initiation b. Transcriptional initiation c. Translational frameshifting d. Transcriptional termination e. Secondary structures 44. The T7 RNA polymerase is unique relative to other DNA-dependent RNA polymerases in : a. The promoter sequences that it recognizes b. The number of subunits in the enzyme c. The speed that it transcribes d. All of the above e. None of the above
45.
Early genes in most viruses are involved in : a. Regulating host functions b. Making RNA polymerases c. Replicating the virus genome d. Virus assembly e. Virus release 46. Genome entry for bacteriophage T7 is due to : a. Transcription by host enzymes b. Transcription by viral enzymes c. Injection d. Pilus retraction e. A and B 47. Why is the initial amount of DNA injected into a host cell on infection by bacteriophage T7 so short? a. So that the host RNA polymerase can bind its promoters b. So that the viral DNA is not degraded by host endonucleases c. So that the viral DNA is not degraded by viral endonucleases d. Because the DNA in the virion is not tightly packed e. So that the viral RNA polymerase can be made 48. Why is it thought that T7 lysozyme inhibits T7 RNA polymerase activity? a. Because T7 RNAP is too fast b. Because the genome is already in the cell c. Because T7 RNAP activity is not required late in infection d. To allow the holin protein to be made e. To serve as a scaffold for virion assembly 49. T7 DNA replication resembles host replication except : a. The requirement for a helicase b. That there is only one replication fork c. That it is “rolling circle” d. That single strands are made e. For the proteins involved 50. Most modern plasmid vectors contain : a. PhiX174 origins of replication b. Podovirus RNA polymerase promoters c. T7 DNA polymerase origins d. T7 holin genes e. All of the
above