Block 9 Viral Replication MCQ's

1. The common cold, polio and hepatitis A can all be caused by a virus of the same family. Which family is this?

Picornaviridae

Poxviridae

Filoviridae

Coronaviridae

The common cold, polio, and hepatitis A are all caused by viruses belonging to the Picornaviridae family. This family of viruses is known for causing a wide range of illnesses in humans, including respiratory and gastrointestinal infections. The viruses in this family are characterized by their small size and single-stranded RNA genome. They are transmitted through respiratory droplets or fecal-oral route and can cause symptoms such as fever, cough, sore throat, and diarrhea.

Explanation

The common cold, polio, and hepatitis A are all caused by viruses belonging to the Picornaviridae family. This family of viruses is known for causing a wide range of illnesses in humans, including respiratory and gastrointestinal infections. The viruses in this family are characterized by their small size and single-stranded RNA genome. They are transmitted through respiratory droplets or fecal-oral route and can cause symptoms such as fever, cough, sore throat, and diarrhea.

2. For swine flu to replicate in the host cell it must carry an enzyme for nucleic acid replication. Which enzyme is this?

RNA-dependent DNA polymerase

DNA dependent DNA polymerase

RNA-dependent RNA polymerase

DNA dependent RNA polymerase

Swine flu is caused by a type of virus known as an RNA virus. RNA viruses replicate their genetic material using an enzyme called RNA-dependent RNA polymerase. This enzyme is responsible for synthesizing new RNA strands using the viral RNA as a template. Therefore, for swine flu to replicate in the host cell, it must carry RNA-dependent RNA polymerase.

Explanation

Swine flu is caused by a type of virus known as an RNA virus. RNA viruses replicate their genetic material using an enzyme called RNA-dependent RNA polymerase. This enzyme is responsible for synthesizing new RNA strands using the viral RNA as a template. Therefore, for swine flu to replicate in the host cell, it must carry RNA-dependent RNA polymerase.

3. A virology research lab (Dead End Empirical Technologies Inc.) engineers a composite virus with the following characteristics: The virion possesses a capsid derived from simian virus 40 (SV40; Polyornaviridae) containing HBV (hepatitis B virus; Hepadnaviridae) gapped dsDNA, HAV (hepatitis A virus; Picornaviridae) RNA-dependent RNA po)ymerase, and human immunodeficiency virus type 1 (HIV-1; Retroviridae) reverse transcriptase. The nucleocapsid is surrounded by an envelope derived from HEK 293 cells (human embryonic kidney 293 cells) containing murine VSV (rnurine vesicular stomatitis virus; Rhabdoviridae) G proteins. If this virion were to infect permissive cells, which kind of virus would be generated?

Simian virus 40 (SV40)

Hepatitis B virus (HBV)

Hepatitis A virus (HAV)

Human immunodeficiency virus type 1 (HIV-1)

Murine vesicular stomatitis virus (V5V)

The correct answer is Hepatitis B virus (HBV) because the composite virus engineered by the virology research lab contains HBV gapped dsDNA. When this virus infects permissive cells, it would generate HBV as the infecting virus carries the genetic material of HBV.

Explanation

The correct answer is Hepatitis B virus (HBV) because the composite virus engineered by the virology research lab contains HBV gapped dsDNA. When this virus infects permissive cells, it would generate HBV as the infecting virus carries the genetic material of HBV.

4. Swine flu is caused by a member of which family of viruses?

Orthomyxoviridae

Filoviridae

Paramyxoviridae

Arenaviridae

Swine flu, also known as H1N1 influenza, is caused by a member of the Orthomyxoviridae family of viruses. This family includes various types of influenza viruses that can infect both humans and animals. The H1N1 virus specifically affects pigs and can occasionally be transmitted to humans, causing flu-like symptoms. Understanding the family of viruses that causes swine flu is important in developing effective prevention and treatment strategies.

Explanation

Swine flu, also known as H1N1 influenza, is caused by a member of the Orthomyxoviridae family of viruses. This family includes various types of influenza viruses that can infect both humans and animals. The H1N1 virus specifically affects pigs and can occasionally be transmitted to humans, causing flu-like symptoms. Understanding the family of viruses that causes swine flu is important in developing effective prevention and treatment strategies.

5. One of the three main shapes for the viral capsid is the icosahedron. How many faces does an icosahedron have?

21

24

20

18

16

An icosahedron is a three-dimensional shape with 20 identical triangular faces. Each face is an equilateral triangle, and there are a total of 20 faces in an icosahedron.

Explanation

An icosahedron is a three-dimensional shape with 20 identical triangular faces. Each face is an equilateral triangle, and there are a total of 20 faces in an icosahedron.

6. What type of virus causes swine flu?

Ds RNA virus

Ds DNA virus

Ss negative sense RNA virus

Ss positive sense RNA virus

The correct answer is ss negative sense RNA virus. Swine flu, also known as H1N1 influenza, is caused by the influenza A virus, which belongs to the family Orthomyxoviridae. This virus has a single-stranded negative sense RNA genome, meaning that it carries its genetic information in the form of RNA and uses the enzyme RNA polymerase to transcribe its RNA into mRNA for protein synthesis. The negative sense RNA is complementary to the viral mRNA, and it must be converted into a positive sense RNA before it can be translated.

Explanation

The correct answer is ss negative sense RNA virus. Swine flu, also known as H1N1 influenza, is caused by the influenza A virus, which belongs to the family Orthomyxoviridae. This virus has a single-stranded negative sense RNA genome, meaning that it carries its genetic information in the form of RNA and uses the enzyme RNA polymerase to transcribe its RNA into mRNA for protein synthesis. The negative sense RNA is complementary to the viral mRNA, and it must be converted into a positive sense RNA before it can be translated.

7. During your fellowship in infectious diseases, you are studying a viral pathogen by manipulating its nucleic acid genorne using molecular biology methods. One morning following a late night at the lab, you accidentally stick yourself in a finger with a syringe containing a suspension of the wild-type nucleic acid genome of the virus you are studying. You therefore consult immediately with the infectious disease specialist on call that day who, after a careful examination of your case, prompts you to return should any signs of infection occur. Five days later you are febrile. Which of the following molecules was in the suspension you accidentally injected yourself with?

Positive-sense single-stranded DNA

Positive-sense single-stranded RNA

Negative-sense single-stranded DNA

Negative-sense single-stranded RNA

The correct answer is positive-sense single-stranded RNA. This is because positive-sense RNA can directly serve as mRNA and can be directly translated into proteins by the host cell's ribosomes. This means that if the injected RNA is positive-sense, it can immediately start replicating and producing viral proteins, leading to an infection.

Explanation

The correct answer is positive-sense single-stranded RNA. This is because positive-sense RNA can directly serve as mRNA and can be directly translated into proteins by the host cell's ribosomes. This means that if the injected RNA is positive-sense, it can immediately start replicating and producing viral proteins, leading to an infection.

8. In the previous example, which virus component would intervene in cell susceptibility?

The HPV-16 capsid protein

The Hantavirus RNA

The Papihantabolavirus matrix protein

The Ebola virus GP peplomer spikes

None of the above

The Ebola virus GP peplomer spikes would intervene in cell susceptibility. These spikes are responsible for attaching to and entering host cells, allowing the virus to infect and replicate within the cell. By interacting with specific receptors on the surface of host cells, the GP spikes enable the virus to gain entry and initiate infection. Therefore, the presence or absence of these spikes can greatly affect the susceptibility of cells to Ebola virus infection.

Explanation

The Ebola virus GP peplomer spikes would intervene in cell susceptibility. These spikes are responsible for attaching to and entering host cells, allowing the virus to infect and replicate within the cell. By interacting with specific receptors on the surface of host cells, the GP spikes enable the virus to gain entry and initiate infection. Therefore, the presence or absence of these spikes can greatly affect the susceptibility of cells to Ebola virus infection.

9. The replicative intermediate of a positive RNA virus is:

The mRNA

The same as the genornic RNA

Identical to the progeny RNA

Negative RNA

Positive RNA

The replicative intermediate of a positive RNA virus is negative RNA. Positive RNA viruses have a single-stranded positive-sense RNA genome, which serves as the mRNA for viral protein synthesis. However, during replication, the positive RNA genome is used as a template to produce a complementary negative RNA strand. This negative RNA strand then serves as a template for the synthesis of multiple positive RNA strands, which become the progeny RNA. Therefore, the replicative intermediate of a positive RNA virus is negative RNA, not the mRNA or the same as the genomic RNA.

Explanation

The replicative intermediate of a positive RNA virus is negative RNA. Positive RNA viruses have a single-stranded positive-sense RNA genome, which serves as the mRNA for viral protein synthesis. However, during replication, the positive RNA genome is used as a template to produce a complementary negative RNA strand. This negative RNA strand then serves as a template for the synthesis of multiple positive RNA strands, which become the progeny RNA. Therefore, the replicative intermediate of a positive RNA virus is negative RNA, not the mRNA or the same as the genomic RNA.

10. Maraviroc is a recently FDA (Food and Drug Administration) approved chemokine receptor antagonist that binds to human chernokine 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?

HIV-1 attachment to the cell

HIV-1 entry into the cell

HIV-1 uncoating

HIV-1 release from the cell

HIV-1 maturation

Maraviroc is a chemokine receptor antagonist that specifically binds to the human chemokine receptor CCR5. Since CCR5 plays a crucial role in the replication cycle of HIV-1, the drug affects the event of HIV-1 entry into the cell. By blocking the interaction between HIV-1 and CCR5, Maraviroc prevents the virus from entering the host cell and inhibits its replication. This makes it an effective treatment option for HIV-1 infection.

Explanation

Maraviroc is a chemokine receptor antagonist that specifically binds to the human chemokine receptor CCR5. Since CCR5 plays a crucial role in the replication cycle of HIV-1, the drug affects the event of HIV-1 entry into the cell. By blocking the interaction between HIV-1 and CCR5, Maraviroc prevents the virus from entering the host cell and inhibits its replication. This makes it an effective treatment option for HIV-1 infection.

11. Researchers discover a new molecule they think could be used as an antiviral against picornaviruses. To test their hypothesis, they perform the following experiment using a cell line permissive to picornavirus infection: Condition 1: The cells are neither treated with the test compound nor exposed to the virus. Condition 2: The cells are not treated with the test molecule but are infected with the virus. Condition 3: The cells are treated with the test molecule but are not exposed to the virus. Condition 4: The cells are treated with the test compound and exposed to the virus. After a 5 minute incubation period, all cell cultures are thoroughly washed to eliminate the test molecule and virus. A fluorescent nucleic acid probe, complementary to the viral RNA, is then used to demonstrate the presence of viral RNA inside the cells by fluorescence microscopy. Results are as follow:

Which viral molecule is the most likely target of this potential antiviral?

RNA

RNA polymerase

Envelope glycoprotein

Envelope lipid

Capsid protein

The experiment involved testing the effect of the test molecule on viral RNA inside the cells. Since the test molecule was able to eliminate the presence of viral RNA, it suggests that the test molecule is targeting a component of the virus that is essential for viral RNA replication or stability. The most likely target in this case is the capsid protein, as it is responsible for protecting the viral RNA inside the virus particle. By targeting the capsid protein, the test molecule could prevent the virus from entering the cells or disrupt the assembly of new virus particles, ultimately inhibiting viral replication.

Explanation

The experiment involved testing the effect of the test molecule on viral RNA inside the cells. Since the test molecule was able to eliminate the presence of viral RNA, it suggests that the test molecule is targeting a component of the virus that is essential for viral RNA replication or stability. The most likely target in this case is the capsid protein, as it is responsible for protecting the viral RNA inside the virus particle. By targeting the capsid protein, the test molecule could prevent the virus from entering the cells or disrupt the assembly of new virus particles, ultimately inhibiting viral replication.

12. The national regulatory body overseeing the transport of biohazard material in your country has asked you to provide an expert opinion concerning the safety level of an engineered composite virus that needs to be shipped from one laboratory to another. The complete virion composition is the following: a capsid derived from Human Papilloma Virus- 16 (HPV) that contains Hantavirus (-) ssRNA. The nucleocapsid is surrounded with a Papihantabolavirus matrix, in turn surrounded by an envelope containing the Ebola virus GP peplomer spikes. If this virus were to infect permissive cells, which kind of virus would be generated?

A Human papillornavirus-16

A Hantavirus

An Ebola virus

A Papihantabolavirus

No virus would be generated

The given composition of the engineered composite virus includes components from multiple viruses such as Human Papilloma Virus-16 (HPV), Hantavirus, Papihantabolavirus, and Ebola virus. However, it is important to note that the composition does not include the necessary components for viral replication and infection of permissive cells. Without these necessary components, the engineered composite virus would not be able to generate any virus upon infecting permissive cells. Therefore, no virus would be generated.

Explanation

The given composition of the engineered composite virus includes components from multiple viruses such as Human Papilloma Virus-16 (HPV), Hantavirus, Papihantabolavirus, and Ebola virus. However, it is important to note that the composition does not include the necessary components for viral replication and infection of permissive cells. Without these necessary components, the engineered composite virus would not be able to generate any virus upon infecting permissive cells. Therefore, no virus would be generated.