Acheson Chap 11

Which of the following diseases is NOT caused by a member of the picornavirus family?

a) Common cold

b) Polio

c) Hepatitis A

d) Influenza

e) Foot-and-mouth disease

d) Influenza

Why is it unlikely that there will ever be an effective vaccine against the rhinovirus, the major cause of the common cold?

a) The immune system is not very effective at attacking rhinoviruses.

b) There are over 100 different serotypes of rhinovirus.

c) The immune system does not protect the nose.

d) The common cold is too fast for the immune system to fight off.

e) Antibodies can not bind to the rhinovirus virion very well.

b) There are over 100 different serotypes of rhinovirus.

The killed Salk and live Sabin vaccines have been used successfully to nearly eliminate which of the following viruses from the human population?

a) Polio

b) Smallpox

c) Measles

d) Hepatitis A

e) Foot-and-mouth disease

a) Polio

Many of the picornaviruses use host cell receptors that have which of the following characteristics?

a) They are phospholipids.

b) They are carbohydrates.

c) They belong to the immunoglobulin superfamily.

d) They are integrins.

e) They are ion channels.

c) They belong to the immunoglobulin superfamily.

Some picornaviruses have depressions, called “canyons”, on the surface of the virions. Which of the following describes the role that these depressions play?

a) They release the viral genome into the host cell.

b) They bind to the host cell receptor.

c) They maintain the stability of the capsid.

d) They bind to antibodies.

e) They adhere to the envelope.

b) They bind to the host cell receptor.

Entry of the poliovirus genome into the host cell involves all of the following EXCEPT:

a) Binding to a host cell receptor

b) Extrusion of the hydrophobic N-terminus of VP1

c) Conformational change of the virion

d) Loss of the internal VP4 protein

e) Acidification of the endosome

e) Acidification of the endosome

The 5’ end of the poliovirus genomic RNA contains all of the following EXCEPT:

a) A 5’ cap

b) An unusually long noncoding region

c) A pyrimidine-rich tract

d) A high degree of RNA secondary structure

e) Multiple AUG start codons

a) A 5’ cap

The poliovirus protease cleaves the cellular eIF-4G protein. Why doesn’t this affect the virus?

a) The virus doesn’t use this protein as its host cell receptor.

b) The virus encodes the poly A tail as part of the genome.

c) The virus encodes its own version of this cellular protein.

d) The virus does not use cap-dependent translation.

e) The virus encodes its own RNA-dependent RNA polymerase.

d) The virus does not use cap-dependent translation.

How does cleavage of the host cell protein eIF-4G give the virus a competitive advantage?

a) It releases translation factors that the virus needs.

b) It inhibits a cellular nuclease that would degrade the viral genome.

c) It prevents translation of host cell mRNAs but not viral genomes.

d) It inhibits host cell defense mechanisms.

e) It releases nucleotides to be used in viral genome replication.

c) It prevents translation of host cell mRNAs but not viral genomes.

Translation initiation of the genomes of picornaviruses require all of the following EXCEPT:

a) IRES at the 5’ end of the genome

b) VPg protein attached to 5’ end of genome

c) Pyrimidine-rich sequence upstream of an AUG

d) Small subunit of ribosome

e) Host cell translation initiation factors

b) VPg protein attached to 5’ end of genome

Since translation of mRNAs in eukaryotic cells produces only a single polypeptide, how do picornaviruses produce multiple proteins from their RNA genome?

a) They produce multiple subgenomic mRNAs.

b) Their genome consists of a multicistronic mRNA.

c) They use multiple IRES regions to translate multiple open reading frames.

d) They have internal translation start sites in their genome.

e) They cleave a single polypeptide into individual proteins.

e) They cleave a single polypeptide into individual proteins.

Which of the following describes the source of the protease that cleaves the picornavirus polyprotein into individual functional proteins?

a) It is a cellular protease.

b) It is brought into the host cell with the virion.

c) It is part of the polyprotein.

d) It is one of the capsid proteins.

e) It is a complex of a viral and a cellular protein.

c) It is part of the polyprotein.

Why do many positive-strand RNA viruses form their genome replication complexes on the surface of cytoplasmic membranes?

a) Genome replication requires cellular membrane bound proteins.

b) This allows the RNA to be replicated close to the site of virion assembly.

c) The membrane acts as a nucleation site to bring all of the proteins together.

d) The membrane protects the viral genome during replication.

e) Fatty acids are required co-factors of the viral polymerase.

c) The membrane acts as a nucleation site to bring all of the proteins together.

The VPg protein from picornaviruses has which of the following function?

a) It acts as a primer for RNA synthesis.

b) It is the RNA-dependent RNA polymerase.

c) It is the protease that cleaves the viral polyprotein.

d) It induces the formation of cellular membranes.

e) It packages the viral genome into capsids.

a) It acts as a primer for RNA synthesis.

Which of the following describes the last step in the maturation of the picornavirus capsid?

a) Assembly of the 5S protomer

b) Packaging of the viral genome

c) Cleavage of P1 polyprotein into VP0, VP1 and VP3

d) Cleavage of VP0 into VP2 and VP4

e) Assembly of the 14S pentamer

d) Cleavage of VP0 into VP2 and VP4

Picornaviruses cause cytopathic effects in infected host cells by doing all of the following EXCEPT:

a) Inhibiting cap-dependent translation of mRNAs

b) Degrading cellular DNA

c) Inhibiting intracellular transport from the ER to the Golgi

d) Cleaving histone H3 protein

e) Inhibiting host cell mRNA synthesis

b) Degrading cellular DNA

In the picornavirus genome, there are several A nucleotides found at the 3’ end of both the positive and negative sense strands. How are these A nucleotides used in replication of the RNA genome?

a) They function as the poly A tail for translation of both strands.

b) They provide energy for the RNA-dependent RNA polymerase.

c) They allow the genome strands to be easily separated.

d) They basepair with the U nucleotide bound to the VPg protein.

e) All of the above are correct.

d) They basepair with the U nucleotide bound to the VPg protein.

The ability of picornaviruses to cause pathogenesis in specific tissues can be localized to which of the following regions of the viral genomic RNA?

a) The RNA-dependent RNA polymerase coding region

b) The 3’ noncoding region

c) The non-structural protein coding region

d) The capsid protein coding region

e) The 5’ noncoding sequence

e) The 5’ noncoding sequence

True or False? Once the viral genome has entered the host cell, poliovirus does not require any of the virion proteins to carry out its infectious cycle.

True

True or False? The poly A tail found at the end of the picornavirus genome is created using the same mechanism as the poly A tails on host cell mRNAs.

False

True or False? The 3C proteinase from picornaviruses can cleave itself out of the intact polyprotein.

True

True or False? The RNA-dependent RNA polymerase from picornaviruses does not require a primer.

False

True or False? Hepatitis A produces less cytopathic effects in infected cells than other picornaviruses.

True