Deck 10: Cucumber Mosaic Virus

Question 1

Which of the following describes the first step in the replication cycle of the cucumber mosaic virus?

A)Synthesis of minus-strand copies of the genome.
B)Synthesis of plus-strand copies of the genome.
C)Copying of viral genome into dsDNA.
D)Copying of the viral genome into mRNA.
E)Translation of the genome into protein.

Answer 1

E

Question 2

The coat protein of cucumber mosaic virus contains a negatively charged domain localized on the internal side of the capsid.Which of the following describes the purpose of this domain?

A)It maintains the structure of the capsid.
B)It associates with the positive charge of the viral RNA.
C)It is involved in release of the viral genome into the host cell.
D)It interacts with the host cell receptor.
E)It is involved in movement of the capsid across the plant cell wall.

Answer 2

B

Question 3

Which of the following has been used as a system to study brome mosaic virus replication?

A)Bacterial cells
B)Yeast cells
C)Insect cells
D)Animal cells
E)Human cells

Answer 3

B

Question 4

Which of the following describes the structures of the genomic RNA segments from cucumber mosaic virus?

A)They have a 5' cap and a 3' poly A tail.
B)They have a 5' IRES and a 3' poly A tail.
C)They have a 5' cap and a 3' terminal tRNA-like structure.
D)They have a 5' phosphate and a 3' terminal tRNA-like structure.
E)They have a protein covalently bound to the 5' end and a 3' poly A tail.

Question 5

All of the following describe a method of introducing Cucumber Mosaic Virus into a healthy plant EXCEPT….

A)Grafting an infected branch
B)Insect feeding
C)Watering with a virus containing solution
D)Mechanical inoculation
E)Infection of seeds

Question 6

Which of the following proteins from cucumber mosaic virus acts at the RNA-dependent RNA polymerase?

A)Protein 1a
B)Protein 2a
C)Protein 2b
D)Movement Protein
E)Coat Protein

Question 7

The 5'-terminal 200nts on the cucumber mosaic virus genome function as a promoter for the synthesis of the minus-strand RNA.

Question 8

Which of the following statements about cucumber mosaic virus is FALSE?

A)It has an enveloped helical nucleocapsid.
B)It has a wide range of host species that it can infect.
C)Its genome is composed of positive-strand RNA.
D)It is transmitted by aphids.
E)It can cause asymptomatic infections in some plants.

Question 9

All of the following describe a function of the movement protein from cucumber mosaic virus EXCEPT:

A)It allows the viral RNA to move between host cells.
B)It interacts with the host cytoskeleton.
C)It dilates the plasmodesmata.
D)It binds to viral genomic RNAs.
E)It causes the viral RNA to be taken up by aphids.

Question 10

How has reassortment played a role in the evolution of cucumber mosaic virus?

A)It has allowed swapping of RNA segments between strains.
B)It has allowed swapping of regions of the genome between strains
C)It has increased mutations in the RNA genomes.
D)It has maintained stability of the viral genome.
E)It has increased genetic bottlenecks.

Question 11

What is the role of the plasmodesmata in the replication of cucumber mosaic virus?

A)They allow release of progeny virions from host cells.
B)They are the sites of entry of capsids into the host cell.
C)They are the sites of viral replication inside of plant cells.
D)They allow movement of virus genomes between neighboring cells.
E)They are involved in assembly of progeny virions.

Question 12

In cucumber mosaic virus,productive infection requires simultaneous entry of all three major RNA segments,each packaged into a separate virion.

Question 13

Plant defenses against RNA viruses involved which of the following?

A)siRNAs
B)RISC
C)Dicer
D)Host RNA-dependent RNA polymerase
E)All of the above are correct.

Question 14

Which of the following statements about satellite RNAs found in cucumber mosaic virus infections is FALSE?

A)They require a cucumber mosaic virus for replication.
B)They are packaged into cucumber mosaic virus capsids.
C)They are small linear RNA molecules.
D)They encode several functional proteins.
E)They can increase the symptoms produced by cucumber mosaic virus.

Question 15

Which of the following enzymes can transfer an amino acid to the 3' end of the genome of cucumber mosaic virus?

A)Elongation factor Tu
B)Aminoacyl tRNA synthetase
C)Nucleotidyltransferase.
D)Ribosomal protein S1.
E)Methyltransferase

Question 16

The methyltransferase domain of the polymerase subunit 1a in the cucumber mosaic virus is responsible for doing with of the following?

A)Separating strands of the viral RNA during replication.
B)Replicating the viral genome.
C)Adding the 5' cap to the viral RNA genome segments.
D)Movement of the viral genome through the plasmodesmata.
E)Inhibiting host ribonucleases.

Question 17

Which of the following characteristics of the cucumber mosaic virus influences the aphid species that can transmit the virus?

A)Amino acid sequence of the coat protein.
B)The replication efficiency of the RNA-dependent RNA polymerase.
C)The specificity of binding to the host cell receptor.
D)The sequence of the 3' end of the viral genomic RNA.
E)The sequence of the IRES at the 5' end of the genomic RNA.

Question 18

In an infected plants,the cucumber mosaic virus replicase complex is associated with the membrane surrounding which of the following cellular organelles?

A)Golgi apparatus
B)Nucleus
C)Mitochondria
D)Central Vacuole
E)Chloroplast

Question 19

Which of the following describes a feature of plant viruses,like cucumber mosaic virus,that is rare or absent in animal viruses?

A)Segmented genomes are each packaged into a single virion.
B)Viral particles are transmitted to new hosts via an insect vector.
C)Viral genomes are composed of ssRNA with a negative sense.
D)Viral genomic RNA has a 5' cap.
E)Segmented genomes are each packaged into separate virions.

Question 20

Which of the following describes the hypersensitive response in plants infected with the cucumber mosaic virus?

A)The virus moves into the vascular tissue and causes a systemic infection.
B)The virus causes an asymptomatic infection.
C)Virus replication is limited to a local region of infection.
D)The plant is completely resistant to the virus.
E)Virus replication only occurs in the newest tissues on the plant.

Question 21

Most cultivars of cucumber are resistant to the cucumber mosaic virus,which means they can be infected but do not show any symptoms of the infection.

Question 22

In lieu of an immune response,plants use RNA silencing to defend against virus infection.

Question 23

Viruses that infect plants must contend with the thick cell wall,which is impedes movement of macromolecules between cells.Describe the mechanisms that cucumber mosaic virus uses to transverse this cell wall to both initiate an infection as well as spread through the plant.

Question 24

Plants infected with cucumber mosaic virus are more tolerant to drought and cold than uninfected plants.

Question 25

Describe how satellite RNAs of the cucumber mosaic virus are act as parasites of the virus.

Question 26

Plant viruses,like cucumber mosaic virus,often package separate RNA genome segments into separate virions.What are the evolutionary advantages and disadvantages of this strategy? What ensures that the plants are infected with all of the necessary genome segments to begin an infection?