Block 9 Micro Viral Replication Prt 1
.JPG "Block 9 Micro Viral Replication Prt 1 - Quiz")
- 1.
Which viral element from previous question would determine cell susceptibility?
- A.
Capsid
- B.
(+) ssRNA
- C.
RNA-dependent RNA polymerase
- D.
Matrix
- E.
G protein
Correct Answer
A. CapsidExplanation
The capsid is the outer protein shell of a virus that protects its genetic material. It plays a crucial role in determining cell susceptibility because it is responsible for attaching to specific receptors on the surface of host cells. The capsid allows the virus to enter the host cell and deliver its genetic material, initiating the infection process. Therefore, the presence and structure of the capsid are essential factors in determining whether a cell is susceptible to a particular virus.Rate this question:
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- 2.
Which enzyme is required for the replication of dsDNA viruses?
- A.
DNA-dependent RNA polymerase
- B.
RNA-dependent DNA polymerase
- C.
RNA-dependent RNA polymerase
- D.
DNA-dependent DNA polymerase
- E.
Reverse transcriptase
Correct Answer
D. DNA-dependent DNA polymeraseExplanation
DNA-dependent DNA polymerase is the enzyme required for the replication of dsDNA viruses. This enzyme is responsible for synthesizing new strands of DNA using a template strand of DNA. It catalyzes the addition of nucleotides to the growing DNA chain, creating a complementary copy of the viral DNA. This process is essential for the replication and propagation of dsDNA viruses.Rate this question:
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- 3.
What is the virion structure indicated by the arrow?
- A.
Envelope
- B.
Nucleus
- C.
Tegument
- D.
Capsid
- E.
Matrix
Correct Answer
D. CapsidExplanation
The virion structure indicated by the arrow is the capsid. The capsid is the protein coat that surrounds the genetic material of a virus. It provides protection for the genetic material and helps in the attachment of the virus to host cells. The capsid is made up of repeating protein subunits called capsomeres, which come together to form the overall structure of the capsid.Rate this question:
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- 4.
What is the function of the structure identified in question 2?
- A.
Transcription of genomic cargo
- B.
Binding of virion to cell
- C.
Membrane fusion and entry
- D.
Translation of genomic cargo
- E.
Protection of genomic cargo
Correct Answer
E. Protection of genomic cargoExplanation
The function of the structure identified in question 2 is to protect the genomic cargo.Rate this question:
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- 5.
What would have been the function(s) of the structure identified in question 2 if the virus had been naked?
- A.
Protection of genomic cargo
- B.
Binding of virion to cell
- C.
Membrane fusion and entry
- D.
Protection of genomic cargo and cell binding
Correct Answer
D. Protection of genomic cargo and cell bindingExplanation
If the virus had been naked, the structure identified in question 2 would have served the function of protecting the genomic cargo and binding to the cell. This means that the structure would have acted as a shield for the genetic material of the virus and also facilitated the attachment of the virus to the host cell.Rate this question:
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- 6.
What enzyme is required for the replication of (-) ssRNA viruses?
- A.
DNA-dependent RNA polymerase
- B.
RNA-dependent DNA polymerase
- C.
RNA-dependent RNA polymerase
- D.
DNA-dependent DNA polymerase
- E.
Reverse transcriptase
Correct Answer
C. RNA-dependent RNA polymeraseExplanation
RNA-dependent RNA polymerase is the correct answer because (-) ssRNA viruses have a single-stranded RNA genome that cannot be directly used as a template for replication. RNA-dependent RNA polymerase is the enzyme that is responsible for synthesizing a complementary RNA strand based on the viral RNA template. This enzyme is essential for the replication of (-) ssRNA viruses. DNA-dependent RNA polymerase is not involved in the replication of RNA viruses, and RNA-dependent DNA polymerase is not relevant to (-) ssRNA viruses. DNA-dependent DNA polymerase is involved in DNA replication, not RNA replication. Reverse transcriptase is an enzyme that is specific to retroviruses and is not required for the replication of (-) ssRNA viruses.Rate this question:
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- 7.
Hepatitis B virus (HBV; Hepadnaviridae), the only known gapped DNA virus to infect humans, requires which polymerases to complete its replicative cycle?
- A.
Cellular RNA-dependent RNA polymerase and reverse transcriptase
- B.
Cellular DNA-dependent RNA polymerase and reverse transcriptase
- C.
Viral RNA-dependent RNA polymerase and reverse transcriptase
- D.
Viral DNA-dependent RNA polymerase and reverse transcriptase
- E.
Viral RNA-dependent DNA polymerase and reverse transcriptase
Correct Answer
B. Cellular DNA-dependent RNA polymerase and reverse transcriptaseExplanation
The correct answer is "Cellular DNA-dependent RNA polymerase and reverse transcriptase." Hepatitis B virus (HBV) is a gapped DNA virus that infects humans. In order to complete its replicative cycle, HBV requires the use of cellular DNA-dependent RNA polymerase and reverse transcriptase enzymes. These enzymes are responsible for transcribing the viral DNA into RNA and then reverse transcribing the RNA back into DNA, allowing for the replication of the virus.Rate this question:
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- 8.
Retroviruses such as the Human immunodeficiency virus type 1 (HIV-1) require which polymerases to complete their replication cycle?
- A.
Viral RNA-dependent DNA polymerase and cellular RNA-dependent RNA polymerase
- B.
Viral RNA-dependent DNA polymerase and viral RNA-dependent RNA polymerase
- C.
Viral RNA-dependent DNA polymerase and cellular DNA-dependent RNA polymerase
- D.
Cellular RNA-dependent DNA polymerase and viral DNA-dependent RNA polymerase
- E.
Cellular RNA-dependent DNA polymerase and viral RNA-dependent DNA polymerase
Correct Answer
C. Viral RNA-dependent DNA polymerase and cellular DNA-dependent RNA polymeraseExplanation
Retroviruses such as HIV-1 require viral RNA-dependent DNA polymerase to convert their RNA genome into DNA, which is an essential step in their replication cycle. Additionally, they also require cellular DNA-dependent RNA polymerase to transcribe the newly formed DNA into RNA, which can then be used for protein synthesis. Therefore, the correct answer is "Viral RNA-dependent DNA polymerase and cellular DNA-dependent RNA polymerase."Rate this question:
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- 9.
A virology research lab (Dead End Empirical Technologies Inc.) engineers a composite virus with the following characteristics: The virion possesses a capsid derived from Human papillomavirus type 16 (HPV-16; Papillomaviridae) containing Rhinovirus type 99 (Picornaviridae) (+) ssRNA and Hepatitis A virus (HAV; Picornaviridae) RNA-dependent RNA polymerase. The nucleocapsid is confined into a Human immunodeficiency virus type 1 (HIV-1; Retroviridae) matrix, which is in turn surrounded by an envelope derived from HEK 293 cells (human embryonic kidney 293 cells) pseudotyped with murine vesicular stomatitis virus (VSV; Rhabdoviridae) G proteins (i. e. the viral envelope contains VSV G proteins). If this virion were to infect permissive cells, which kind of virus would be generated?
- A.
HPV-16
- B.
Rhinovirus type 99
- C.
HAV
- D.
HIV-1
- E.
VSV
Correct Answer
B. Rhinovirus type 99Explanation
The composite virus engineered by the virology research lab contains Rhinovirus type 99 RNA. Therefore, if this virion were to infect permissive cells, it would generate Rhinovirus type 99.Rate this question:
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- 10.
Which viral element from question 8 would determine cell susceptibility?
- A.
Capsid
- B.
(+) ssRNA
- C.
RNA-dependent RNA polymerase
- D.
Matrix
- E.
G protein
Correct Answer
E. G proteinExplanation
The G protein is the viral element that would determine cell susceptibility. The G protein is responsible for binding to specific receptors on the surface of host cells, allowing the virus to enter and infect the cell. The presence or absence of the G protein on the virus determines which cells it can attach to and infect, making it a crucial factor in determining cell susceptibility.Rate this question:
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- 11.
What would be the composition of the progeny virus?
- A.
(+) ssRNA & capsid
- B.
(+) ssRNA, capsid & envelope
- C.
(+) ssRNA, capsid, matrix & envelope
- D.
(+) ssRNA, polymerase, capsid, matrix & envelope
- E.
(+) ssRNA, polymerase & capsid
- F.
(+) ssRNA, polymerase, capsid & envelope
Correct Answer
A. (+) ssRNA & capsidExplanation
The correct answer is (+) ssRNA & capsid. This is because the progeny virus is a positive single-stranded RNA virus, which means it has a single-stranded RNA genome. The capsid is the protein coat that surrounds and protects the viral genome. Therefore, the composition of the progeny virus would include the positive single-stranded RNA genome and the capsid.Rate this question:
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- 12.
7.1) In theory, what would be the outcome of a non-vaccinated, laboratory technician accidentally infecting him(her)self with a liquid suspension of Measles virus (+) ssRNA contained in a syringe?
- A.
Viral replication/Disease
- B.
Viral replication/No disease
- C.
No viral replication/Disease
- D.
No viral replication/No disease
- E.
A & B
Correct Answer
E. A & BExplanation
If a non-vaccinated laboratory technician accidentally infects themselves with a liquid suspension of Measles virus, the outcome would be both viral replication and disease. This is because the Measles virus is capable of replicating in the body and causing an infection, leading to the development of symptoms and disease. The technician's lack of vaccination would leave them susceptible to the virus, allowing it to replicate and cause illness. Therefore, options A and B are both correct.Rate this question:
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- 13.
7.2) In theory, what would be the outcome of a non-vaccinated, laboratory technician accidentally infecting him(her)self with a liquid suspension of Ebola virus (-) ssRNA contained in a syringe?
- A.
Viral replication/Disease
- B.
Viral replication/No disease
- C.
No viral replication/Disease
- D.
No viral replication/No disease
Correct Answer
D. No viral replication/No diseaseExplanation
If a non-vaccinated laboratory technician accidentally infects themselves with a liquid suspension of Ebola virus, the outcome would be no viral replication and no disease. This is because the technician's immune system would recognize the virus as foreign and mount an immune response to eliminate it before it can replicate and cause disease. Without viral replication, the individual would not develop any symptoms or illness associated with Ebola virus infection.Rate this question:
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- 14.
7.3) Under natural conditions (i. e. not in laboratory or immunization settings), which of the following viruses would be the simplest virus capable of completing its infectious cycle?
- A.
A virus that would consist of its nucleic acid and its capsid
- B.
A virus that would consist of its nucleic acid, its corresponding polymerase and its capsid
- C.
A virus that would consist of its nucleic acid, its corresponding polymerase, its capsid and its envelope
- D.
A virus that would consist of its nucleic acid, its corresponding polymerase, its capsid, its matrix and its envelope
- E.
A virus that would consist of its nucleic acid, its corresponding polymerase, its capsid, its matrix, its tegument and its envelope
Correct Answer
A. A virus that would consist of its nucleic acid and its capsidExplanation
That would have to be a naked, (+) ssRNA virus, such as the Picornaviridae, Caliciviridae, Astroviridae and Hepeviridae, as well as some naked, DNA viruses such as papillomaviruses and polyomaviruses.Rate this question:
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- 15.
Which statement best applies to virions?
- A.
Virions are the vessels that protect and deliver viral self-replicating proteins from susceptible host cells to other susceptible host cells.
- B.
Virions are the vessels that protect and deliver viral self-replicating proteins from permissive host cells to other permissive host cells
- C.
Virions are vessels that protect and deliver viral genomes from susceptible host cells to other susceptible host cells.
- D.
Virions are vessels that protect and deliver viral genomes from permissive host cells to other permissive host cells.
- E.
Virions are vessels that need to be processed by viral proteases in order to become fully infectious viruses.
Correct Answer
D. Virions are vessels that protect and deliver viral genomes from permissive host cells to other permissive host cells.Explanation
One could argue that “C” is also a right answer, and this would be right; but “D” is a better answer because it is more inclusive. For those wondering why “E” is wrong, virions are infectious viruses by definition hence the maturation process has already occurred (maturation often being dependent on viral proteolytic activity such as HIV’s protease or influenza’s neuraminidase).Rate this question:
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- 16.
Which of the following accurately describe(s) the actual order(s) of (a) viral replication cycle(s)? (More than one answer is possible)
- A.
Attachment---Entry---Uncoating---Genome replication---Assembly---Release---Maturation
- B.
Attachment---Entry---Genome replication---Uncoating---Assembly---Release---Maturation
- C.
Attachment---Entry---Uncoating---Genome replication---Release---Assembly---Maturation
- D.
Attachment---Uncoating---Entry---Genome replication---Assembly---Release---Maturation
- E.
Attachment---Entry---Uncoating---Assembly---Genome replication---Release
Correct Answer(s)
A. Attachment---Entry---Uncoating---Genome replication---Assembly---Release---Maturation
C. Attachment---Entry---Uncoating---Genome replication---Release---Assembly---Maturation
E. Attachment---Entry---Uncoating---Assembly---Genome replication---ReleaseExplanation
“C” and “E” could also be correct under some circumstances; “C” could represent the case of HIV whereas “E” could represent the case of HBV. This being said, I would expect most of you to answer “A” because it is the one presented in your material as the default one and we haven’t gone through specific viruses at this pointRate this question:
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- 17.
Which of the following accurately describes cell susceptibility to viral infection?
- A.
Host cell possesses all the components required for viral replication
- B.
Host cell possesses the proper receptor(s) required for viral binding
- C.
Host cell possesses the appropriate polymerase(s) required for viral replication
- D.
Host cell possesses the elements required for initiating viral uncoating
- E.
Host cell possesses the appropriate cellular transport machinery required for trafficking viral subunits to sites of virion assembly
Correct Answer
B. Host cell possesses the proper receptor(s) required for viral bindingExplanation
The correct answer is "Host cell possesses the proper receptor(s) required for viral binding." This means that the host cell has the specific receptors on its surface that can bind to the viral particles and allow them to enter the cell. Without these receptors, the virus would not be able to infect the cell.Rate this question:
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- 18.
IN GENERAL, what is the order of the events occurring during sequential viral assembly?
- A.
Capsid protein synthesis first---Genome replication second---Packaging of genome into preformed capsid third
- B.
Genome replication first---Capsid protein synthesis second---Packaging of genome into preformed capsid third
- C.
Capsid protein synthesis first---Packaging of genome into preformed capsid second---Genome replication third
- D.
Capsid proteins are synthesized while the genome is being replicated, and assembly progresses as the capsid subunits are formed and the genome elongated.
- E.
Viral assembly is a series of random events taking place invariably in the cytosol, i. e. there is no order.
Correct Answer
B. Genome replication first---Capsid protein synthesis second---Packaging of genome into preformed capsid thirdExplanation
“A” could be exceptionally, borderline, right, but “B” is by far more common. “D” corresponds to coordinated assembly.Rate this question:
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- 19.
Which of the following assertions is false?
- A.
Viral packaging requires packaging signals
- B.
Viral packaging relates to the incorporation of the genomic nucleic acid into the capsid.
- C.
Viral packaging can be done prior to capsid formation
- D.
Viral assembly relates to the incorporation of virally encoded enzymes into the capsid.
- E.
Viral assembly relates to the incorporation of tRNAs.
Correct Answer
C. Viral packaging can be done prior to capsid formationExplanation
Viral packaging refers to the process of incorporating the genomic nucleic acid into the capsid. This process typically occurs after capsid formation. Therefore, the assertion that viral packaging can be done prior to capsid formation is false.Rate this question:
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- 20.
Maraviroc is an FDA (Food and Drug Administration) approved chemokine receptor antagonist that binds to human chemokine receptor CCR5. Given the function of CCR5 in the replication cycle of Human immunodeficiency virus type 1 (HIV-1), which event is affected by this drug?
- A.
Entry
- B.
Uncoating
- C.
Assembly
- D.
Release
- E.
Maturation
Correct Answer
A. EntryExplanation
Maraviroc, as a chemokine receptor antagonist, binds to the human chemokine receptor CCR5. This receptor plays a crucial role in the entry of Human immunodeficiency virus type 1 (HIV-1) into host cells. By binding to CCR5, Maraviroc prevents the virus from attaching to and entering the host cells, thereby inhibiting the initial step of the viral replication cycle, which is the entry of HIV-1 into the host cells.Rate this question:
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Current Version
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Mar 16, 2023Quiz Edited by
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Jun 07, 2012Quiz Created by
Chachelly
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