Deck 17: Bunyaviruses

Question 1

How many genome segments do bunyaviruses have?

A)1
B)2
C)3
D)5
E)8

Answer 1

C

Question 2

Bunyaviruses that have been reassorted for the M segment have lost their virulence.Which of the following describes the conclusion from this experiment?

A)The envelope proteins are responsible for virulence.
B)The RNA polymerase is responsible for virulence.
C)The non-structural protein is responsible for virulence.
D)The nucleocapsid protein is responsible for virulence.
E)Virulence is not controlled by any of the above.

Answer 2

A

Question 3

What do bunyaviruses use to prime the transcription of their viral mRNAs?

A)A cellular protein
B)A viral protein
C)Fragments of cytoplasmic capped mRNAs.
D)Fragments of nuclear capped mRNAs.
E)The do not use primers for mRNA transcription.

Answer 3

C

Question 4

A reverse genetics system for bunyaviruses has been established by doing which of the following?

A)Expressing negative-strand viral genomes in mosquito cells.
B)Expressing negative-strand viral genomes in mammalian cells.
C)Expressing positive-strand viral genomes in mosquito cells.
D)Expressing positive-strand viral genomes in mammalian cells.
E)By transfecting mammalian cells with naked negative-strand viral RNA.

Question 5

The S genome segment from bunyaviruses encodes which of the following proteins?

A)The RNA polymerase protein.
B)The envelope glycoproteins.
C)The nucleocapsid protein.
D)Both the nucleocapsid protein AND the non-structural protein.
E)Either b or d can be correct,depending on the virus.

Question 6

In the RNA viruses with segmented genomes,which of the following explains antigenic shift?

A)Lack of RNA editing by the RNA-dependent RNA polymerase.
B)Lack of proof-reading by the RNA-dependent RNA polymerase.
C)Exchange of the glycoproteins between two virions.
D)Exchange of genome segments between two virions.
E)All of the above are correct.

Question 7

What is the definition of ambisense coding?

A)One of the viral segments is positive-sense RNA and the other is negative sense.
B)One of the viral segments is DNA and the other is RNA.
C)One end of a viral segment is positive-sense RNA and the other is negative-sense.
D)One viral segment codes for structural proteins and the other codes for non-structural proteins.
E)Only one viral segment is packaged into each viral particle.

Question 8

In the bunyaviruses,which of the following viral proteins is proposed to regulate the transition from production of mRNAs to genome replication?

A)The N (nucleocapsid protein)
B)The M (matrix protein)
C)The G (glycoprotein)
D)The L (polymerase protein)
E)The NS (non-structural protein)

Question 9

The mechanism for how bunyaviruses package one of each of their genome segments is well understood.

Question 10

Which of the following describes a similarity between bunyaviruses and flaviviruses?

A)They both have positive-strand RNA virus genomes.
B)They both have negative-strand RNB virus genomes.
C)They both have members that are transmitted by insects.
D)The both have members that only replicate in insects.
E)The both similar virion structures.

Question 11

Which of the following bunyaviruses is NOT transmitted by an insect vector?

A)Tomato spotted wilt virus
B)Crimean-Congo hemorrhagic fever virus
C)Rift Valley Fever virus
D)Hantaan virus
E)La Crosse virus

Question 12

The bunyavirus Sin Nombre caused a severe respiratory infection in Asia in 2003.

Question 13

Which of the following could be the source of new pathogenic bunyavirus infections in humans?

A)Acquisition of new viruses from bats.
B)Evolution of viruses that over stimulate the immune system.
C)Reassortment between two viruses in mosquitoes.
D)Transovarial transmission of a bunyavirus.
E)Infection of domestic animals.

Question 14

Which of the following describes an interesting feature of the envelope glycoproteins from bunyaviruses?

A)They are exported out to the plasma membrane of the cell.
B)They are retained in the Golgi membrane.
C)They are not glycosylated.
D)They are cleaved into three segments.
E)80% of the proteins made are secreted out of the cell.

Question 15

Which of the following describe the differences between bunyaviruses and filoviruses?

A)Bunyaviruses have a monopartite genome and filoviruses are segmented.
B)Bunyaviruses have a segmented genome and filoviruses are monopartite.
C)Bunyaviruses have a naked virion and filoviruses are enveloped.
D)Bunyaviruses have an enveloped virions and filoviruses are naked.
E)Only filoviruses can be transmitted via an insect vector.

Question 16

How are bunyaviruses maintained in nature over time?

A)They can be maintained in mosquito eggs.
B)They can stay viable in the soil.
C)They are maintained in water samples.
D)They cause persistent infections in humans.
E)All of the above.

Question 17

Bunyavirus mRNAs can be translated while they are still being transcribed by the viral RNA polymerase.Why has this been shown to be important for this group of viruses?

A)Transcription prevents premature termination of translation.
B)Translation prevents premature termination of transcription.
C)It allows the virus to use attenuation as a regulatory mechanism.
D)The virus can translate the structural protein on the rough ER ribosomes.
E)It prevents cellular ribosomes from translating cellular mRNAs.

Question 18

Viruses,such as bunyaviruses,that use ambisense coding,do which of the following to produce their mRNAs?

A)They translate the positive end of the viral segment first.
B)They translated the negative end of the viral segment first.
C)They copy the positive end of the viral segment into mRNA first.
D)They copy the negative end of the viral segment into mRNA first.
E)They translate the entire ambisense viral segment into protein first.

Question 19

Which of the following is a type of human illness NOT caused by a member of the bunyavirus family?

A)fever
B)encephalitis
C)hemorrhagic fever
D)fatal respiratory syndrome
E)arthritis

Question 20

Which of the following are typically the largest proteins coded for by RNA viruses?

A)The nucleocapsid protein.
B)The RNA polymerase.
C)The matrix protein.
D)The envelope glycoproteins.
E)The regulatory protein.

Question 21

Bunyaviruses remove the 5' ends of cellular mRNAs.Describe the mechanism that these viruses use to do this and how the virus uses these RNA fragments.What advantage does this provide to the virus?

Question 22

Synthesis of the positive-strand antigenome of bunyaviruses uses the same capped primer as the synthesis of the mRNAs.

Question 23

Bunyaviruses appear to use a pH dependent mechanism for entry into host cells.

Question 24

Bunyavirus mRNAs are translated while they are still being transcribed.

Question 25

The genome segments of bunyaviruses can form panhandles and circularize due to complementary 3' and 5' ends.

Question 26

Explain how genetic drift and shift can lead to the emergence of new strains of bunyavirus that are pathogenic in humans.