Question 1

Which of the following is used as the template for the production of more reovirus genome segments in the virus factories?

Accepted Answer

Reoviruses have a double-stranded RNA (dsRNA) genome. During infection, the dsRNA serves as a template to produce single-stranded positive sense RNA (mRNAs), which are then used both as templates for protein synthesis and as templates for the production of more genome segments in the virus factories.

Question 2

Which of the following describes the type of type of nucleic acids found in reovirus genomes?

Accepted Answer

Reovirus genomes consist of double-stranded RNA.

Question 3

Reoviruses cause cell-cycle arrest in infected cells.At what point in the cell cycle do these viruses halt the cell cycle?

Accepted Answer

D

Question 4

Reoviruses keep their genome sequestered inside the inner capsid throughout the entire infectious cycle.Which of the following is the best explanation for why do they not release the genome segments out into the cytoplasm?

Accepted Answer

Reoviruses keep their genome sequestered inside the inner capsid to avoid activation of the interferon response, which would alert the immune system to the presence of the virus. If the genome segments were released into the cytoplasm, they would be detected as foreign and trigger the interferon response.

Question 5

Which of the following factors affect the abundance of the viral proteins produced during infection with a reovirus?

Accepted Answer

All of the factors listed can affect the abundance of viral proteins produced during infection with a reovirus. The length of the mRNA can affect stability and translational efficiency, while the sequences surrounding the start codon can influence the efficiency of translation initiation. The length and secondary structure of the 5' noncoding sequences can also affect translation initiation and efficiency.

Question 6

How has the creation of reassortant viruses helped in the study of reoviruses?

Accepted Answer

The creation of reassortant viruses, which are viruses with mixed genome segments from different strains, has allowed scientists to associate specific viral proteins with their functions. By swapping out specific genome segments and studying the resulting reassortant viruses, researchers can identify which segments are responsible for certain aspects of the virus, such as host range or virulence. This approach has been particularly useful in the study of reoviruses, which have ten genome segments that can be easily manipulated to create reassortants.

Question 7

Which of the following describes the mechanism used by reoviruses to ensure that one of each of the 10 genome segments is package into the virion?

Accepted Answer

The answer of Which of the following describes the mechanism...

Question 8

The RNA-dependent RNA polymerase of reoviruses is released into the cytoplasm along with the double-strand RNA segments.

Accepted Answer

The RNA-dependent RNA polymerase of reoviruses is contained within the viral core particles, and transcription of the double-stranded RNA segments occurs within these core particles, not in the cytoplasm.

Question 9

Reoviruses can cause myocarditis in infected mice but it is through a different mechanism than used by most other viruses that cause this disease.Which of the following describes the reason reoviruses destroy heart muscle?

Accepted Answer

Reoviruses induce cytopathic effects, which means they cause structural changes in infected cells that can lead to cell death. This destruction of heart muscle could explain the myocarditis observed in infected mice.

Question 10

All of the following are enzymatic activities found within the virion core of reoviruses EXCEPT….

Accepted Answer

Reoviruses do not have peptidyl transferase activity within their virion core. The other enzymatic activities listed (RNA-dependent RNA polymerase, RNA helicase, phosphatase to remove 5' end of mRNAs, methyltransferase) are all found within the virion core of reoviruses.

Question 11

Some reoviruses are transmitted by insects and are therefore examples of arboviruses.

Accepted Answer

Arboviruses are viruses that are transmitted by arthropods, such as mosquitoes, ticks, and sandflies. Some reoviruses, such as Colorado tick fever virus, are examples of arboviruses.

Question 12

What is the source of the nucleotide triphosphates used to make reovirus mRNAs?

Accepted Answer

The answer of What is the source of the nucleotide...

Question 13

Reoviruses have been used to study viral pathogenesis in mice.Using virus reassortants,which of the following has been shown to be a major determinant for infection of the nervous system in a mouse?

Accepted Answer

By creating virus reassortants with different surface proteins, researchers have shown that the ability of a reovirus to infect the nervous system in mice depends on its ability to bind to specific receptors on host cells. Therefore, the binding of the virus to different host cell receptors is a major determinant for infection of the nervous system.

Question 14

Which of the following mechanisms explain how reovirus mRNAs acquire their poly(A)tail?

Accepted Answer

The answer of Which of the following mechanisms explain how...

Question 15

Infection of a cell with a reovirus can activate which of the following cellular proteins or processes?

Accepted Answer

Reovirus infection can activate multiple cellular responses, including the activation of NF-κB, IRF-3, apoptosis, and caspases, which are involved in the immune response and programmed cell death.

Question 16

Which of the following describes an interesting feature of the reovirus virion?

Accepted Answer

Reovirus virions are unique in that their capsid consists of two concentric shells, both exhibiting icosahedral symmetry, which is a key structural feature distinguishing them from many other viruses.

Question 17

Which of the following reovirus proteins is implicated in selective inhibition of PKR activation in infected cells?

Accepted Answer

F1F1F1S1F1F1F103 is implicated in selective inhibition of PKR activation in infected cells.

Question 18

Which of the following accounts for the majority of the viral mRNA synthesized in a reovirus infected cell?

Accepted Answer

Reoviruses have a double-stranded RNA genome. The majority of the viral mRNA in a reovirus-infected cell is synthesized from newly synthesized double-stranded RNA segments within the cytoplasm, not from the incoming viral RNA or RNA segments found in the nucleus or lysosomes.

Question 19

Which of the following is the first step in the expression of reovirus proteins during the infection?

Accepted Answer

The first step in the expression of reovirus proteins during infection is the copying of the negative strand of each genome segment into mRNA. This mRNA can then be translated into protein by the host cell machinery.

Question 20

Which of the following is NOT a host cell protein that can be used as a receptor by a reovirus?

Accepted Answer

While the remaining answer choices (B, C, D, and E) are all host cell proteins that can be used as a receptor by a reovirus, cathepsin is not.

Quiz 19: Reoviruses