Deck 8: Viral Replication Strategies

Question 1

A drug is designed which blocks the attachment of the Epstein Barr virus to its receptor.Which physiological effect might be observed in patients receiving this medication?

A)Increased antibody production
B)Decreased antibody production
C)Less cellular adhesion in some tissues
D)Transport of the drug into cells by facilitated carrier proteins
E)Decreased cell signaling between lymphocytes

Answer 1

A

Question 2

Most non-enveloped animal viruses enter the host cell by

A)membrane fusion.
B)pinocytosis.
C)injection of nucleic acid into host cell.
D)lysis of host cell membrane.
E)receptor mediated endocytosis.

Answer 2

E

Question 3

The influenza virus gains entry into a host cell by

A)direct injection of its nucleic acid.
B)receptor-independent endocytosis.
C)lysis of the cell membrane.
D)receptor-mediated endocytosis.
E)pinocytosis.

Answer 3

D

Question 4

Which of the following techniques would most efficiently identify a virus causing an emerging disease?

A)SDS electrophoresis
B)Electrophoresis and modified Western blotting
C)PCR and DNA sequencing
D)DNA microarray technology
E)Culture of virally-infected cells

Question 5

Which of the following cellular functions is unlikely for a host cell receptor recognized by a virus?

A)Hormone receptor
B)Gated sodium channel protein
C)Active transport protein
D)Cell-cell signaling
E)Glycolytic enzyme

Question 6

E)coli strain K12 is susceptible to infection by phage T2.T2 binds to K12 via two attachment proteins.These two proteins specifically bind to the following two host cell receptor proteins found on the surface of strain K12.

A)lipopolysaccharide and cytochrome c
B)flagellin and cytochrome c
C)OmpF and lipopolysaccharide
D)OmpF and flagellin
E)flagellin and lipopolysaccharide

Question 7

A non-enveloped virus will have its attachment proteins present in its:

A)Envelope spikes
B)Capsid spikes
C)Cell wall spikes
D)Cytoplasm
E)Plasma membrane

Question 8

The second step in viral replication is entry.For bacteriophage,entry usually involves

A)phagocytosis.
B)receptor-mediated endocytosis.
C)direct entry of the nucleic acid into the cell.
D)membrane fusion mechanism of entry.
E)digestion of the peptidoglycan.

Question 9

Plant viruses often gain entry into host cells by

A)receptor mediated endocytosis.
B)injury caused by insects to host cell.
C)membrane fusion mechanism.
D)pinocytosis.
E)direct injection of nucleic acid into the host cell.

Question 10

The influenza virus is most likely to bind to a host cell receptor with amino acid sequence similarity to:

A)Sialic acid
B)CR2
C)OmpF
D)CD4
E)ICAM-1

Question 11

Antibody produced in response to a viral infection is able to neutralize viral attachment by

A)binding nucleic acid polymerases and preventing viral nucleic acid replication.
B)binding ribosomes and preventing viral protein translation.
C)activating macrophages to phagocytize the virus.
D)binding to the viral attachment proteins to prevent attachment to the host cell receptor.
E)binding to the host cell receptor molecule to prevent the attachment of the virus.

Question 12

Most non-enveloped viruses enter the host cell by receptor-mediated endocytosis.The virus or its nucleic acid is able to leave the endosome and enter the cytoplasm

A)through the production of a lipase to lyse the endosome membrane.
B)as a result of digestive enzymes found in the endosome.
C)through the fusion of the capsid proteins with endosome proteins by digesting the endosomal membrane.
D)through pores formed from viral capsid proteins.

Question 13

Structurally,the drug Fuzeon is similar to:

A)the HIV fusion peptide
B)HIV gp120
C)Unfolded HIV gp41
D)Folded HIV gp41
E)CD4 receptor

Question 14

The influenza virus gains entry into a host cell by an endocytotic process.The viral nucleocapsid leaves the endosome and enters the cytoplasm through a membrane fusion mechanism.Fusion of the viral envelope with the endosomal membrane is facilitated by

A)a conformation change in the hemagglutinin to expose a fusion protein.
B)the production of a lipase by the influenza virus.
C)sialic acid residues of the receptor proteins.
D)specific viral protein recognition of pores in the endosome vesicle.
E)the production of proteases by the influenza virus.

Question 15

The SARS virus is most likely to bind a receptor similar in amino acid sequence to:

A)CD4
B)ICAM-1
C)Bgp1a
D)CR2
E)Sialic acid

Question 16

The ability of a virus or bacteriophage to specifically attach to a host cell occurs through the interactions of the viral attachment protein with the host cell receptor.This binding determines

A)the rate of viral DNA replication.
B)the host range.
C)the mechanism of viral entry.
D)whether or not the virus will contain an envelope.
E)the rate of viral RNA replication.

Question 17

The viral attachment protein specifically binds to a host cell receptor.All of the following are examples of known host cell receptors except

A)DNA.
B)proteins.
C)glycoproteins.
D)lipopolysaccharides.
E)sialic acids.

Question 18

Fuzeon is an antiviral drug that prevents membrane fusion for entry into the cell by HIV.The mode of action for this drug is

A)to prevent formation of a viral lipase that lyses the cell membrane.
B)to prevent attachment of the virus to the host cell receptor.
C)to interrupt receptor mediated endocytosis.
D)to bind to gp41 membrane fusion protein of HIV.
E)to digest the envelope of HIV,thereby preventing membrane fusion.

Question 19

Most likely,"host specificity" of a virus is determined by

A)the type of nucleic acid it contains.
B)the presence or absence of an envelope.
C)viral enzymes.
D)interactions between viral attachment proteins and host cell receptors.
E)viral nucleic acid replication strategies.

Question 20

Antiviral drugs such as Maraviroc that act at the level of host recognition are designed to

A)prevent endocytotic vesicle formation.
B)prevent virus binding to the host cell receptor.
C)enhance antibody production.
D)inactivate viral nucleic acid polymerases.
E)bind to viral metabolic enzymes.

Question 21

Which of these viruses presents the best experimental model for site-directed mutagenesis research on viral replication?

A)Poxvirus
B)Poliovirus
C)HIV
D)SV40
E)HPV

Question 22

The Baltimore classification scheme for viruses divides all viruses into seven groups based on

A)their shape and host.
B)host and presence or absence of an envelope.
C)how they produce mRNA and replicate their genome.
D)their shape and presence or absence of an envelope.
E)their shape,host,and presence or absence of an envelope.

Question 23

Protease inhibitors are routinely used in the treatment of an HIV infection to slow down the progression of the disease.How do these inhibitors work?

A)They inhibit the process of translation for the production of viral proteins.
B)They inhibit the process of entry by interacting with the fusion peptide.
C)They block the attachment process by interacting with the viral attachment protein.
D)They inhibit the proteolytic modification of the viral capsid to form an infectious virion.
E)They inhibit the activity of the viral enzyme reverse transcriptase.

Question 24

Bacteriophage T4 uses which of its component molecules to assist in genome entry into a bacterial cell:

A)Phage head proteins
B)Tail core protein
C)Tail fiber protein
D)Nucleic acids
E)None is a correct choice

Question 25

Class V viruses,negative sense single-stranded RNA viruses,utilize the following polymerase for mRNA synthesis

A)viral DNA-dependent RNA polymerase.
B)host cell RNA-dependent RNA polymerase.
C)host cell DNA-dependent RNA polymerase.
D)viral RNA-dependent RNA polymerase.
E)don't need polymerase,nucleic acid can act directly as mRNA.

Question 26

Class I viruses,double-stranded DNA viruses,usually utilize the following polymerases for (i)mRNA synthesis and (ii)DNA replication

A)(i)host cell DNA-dependent RNA polymerase and (ii)host cell DNA-dependent DNA polymerase.
B)(i)viral DNA-dependent RNA polymerase and viral (ii)DNA-dependent DNA polymerase.
C)(i)viral RNA-dependent RNA polymerase and (ii)host cell DNA-dependent DNA polymerase.
D)(i)host cell RNA-dependent RNA polymerase and (ii)host cell DNA-dependent DNA polymerase.
E)(i)viral RNA-dependent RNA polymerase and (ii)viral DNA-dependent DNA polymerase.

Question 27

Bacteriophage lambda enters the lytic phase of its life cycle when

A)high levels of cI and high levels of cro proteins are present in bacterial cells
B)low levels of cI and high levels of cro proteins are present in bacterial cells
C)high levels of cI and low levels of cro proteins are present in bacterial cells
D)low levels of cI and low levels of cro proteins are present in bacterial cells
E)none of these conditions lead to lysis

Question 28

Most RNA viruses utilize

A)an RNA-dependent RNA polymerase.
B)a DNA-dependent RNA polymerase.
C)an RNA-dependent DNA polymerase.
D)a DNA-dependent DNA polymerase.
E)reverse transcriptase.

Question 29

Which of these viruses is most likely to possess a T-antigen equivalent?

A)Bacteriophage T4
B)Poxvirus
C)Poliovirus
D)HPV
E)HIV

Question 30

Phage lambda (λ)is referred to as a temperate phage.What is a temperate phage?

A)A phage that always causes a lytic infection.
B)The same thing as a lysogen.
C)A phage that only lyses a cell at a specific temperature.
D)A phage that can undergo either a lytic or lysogenic phase of replication.
E)A bacteriophage that contains single-stranded RNA for its genome.

Question 31

Which of the following terms is not an appropriate descriptor for the genome of the poliovirus?

A)infectious RNA
B)mRNA
C)positive sense RNA
D)ss RNA (+)
E)negative sense RNA

Question 32

Exposing viral genetic material to host replicative enzymes is the least challenging for:

A)Bacteriophages
B)Non-enveloped plant viruses
C)Enveloped plant viruses
D)Non-enveloped animal viruses
E)Enveloped animal viruses

Question 33

RNAse H activity permits

A)degradation of RNA in a heteroduplex and synthesis of dsDNA
B)degradation of DNA in a heteroduplex and synthesis of dsRNA
C)degradation of RNA in a heteroduplex and synthesis of ssDNA
D)degradation of DNA in a heteroduplex and synthesis of ssRNA
E)none of these activiies occur

Question 34

Select the answer choice in which HIV replication enzymes are listed in the order in which they act.

A)DNA-dependent RNA polymerase,RNAse H,integrase,RNA-dependent RNA polymerase
B)RNA-dependent DNA polymerase,RNAse H,integrase,DNA-dependent RNA polymerase
C)RNA-dependent RNA polymerase,RNAse H,integrase,DNA-dependent RNA polymerase
D)RNAse H,RNA-dependent RNA polymerase,integrase,DNA-dependent RNA polymerase
E)integrase,RNA-dependent DNA polymerase,RNAse H,DNA-dependent RNA polymerase

Question 35

The Baltimore classification scheme classifies viruses based on their mechanism of mRNA and genome synthesis.Using this classification scheme,all viruses are placed into one of ______ classes.

A)seven
B)five
C)four
D)ten
E)twenty five

Question 36

For most double-stranded DNA eukaryal viruses,DNA replication occurs in the _________ and translation occurs in the __________.

A)cytoplasm,cytoplasm
B)cytoplasm,nucleus
C)nucleus,nucleus
D)nucleus,cytoplasm
E)mitochondria,cytoplasm

Question 37

Bacteriophage lambda maintains the lysogenic phase of its life cycle when

A)high levels of cI and high levels of cro proteins are present in bacterial cells
B)low levels of cI and high levels of cro proteins are present in bacterial cells
C)high levels of cI and low levels of cro proteins are present in bacterial cells
D)low levels of cI and low levels of cro proteins are present in bacterial cells
E)none of these conditions maintains lysogeny

Question 38

Which choice includes all viruses using host cell DNA-dependent RNA polymerase?

A)I,II,IV,V
B)III,IV,V,VI
C)I,II,VI,VII
D)1,III,IV,V
E)II,III,VI,VII

Question 39

Class III viruses,double-stranded RNA viruses,utilize the following polymerase for genome synthesis

A)host cell RNA-dependent RNA polymerase.
B)host cell DNA-dependent RNA polymerase.
C)viral RNA-dependent RNA polymerase.
D)viral DNA-dependent RNA polymerase.
E)viral DNA-dependent DNA polymerase.

Question 40

During infection of a cell,a poliovirus virion undergoes all of the events listed except:

A)loss of VP4
B)loss of VP1
C)reduction in virion particle size
D)PVR binding
E)135S virion size after binding host cell receptor

Question 41

A hypothetical anti-influenza drug might have all of the following effects on susceptible respiratory cells except

A)stimulation of sialic acid receptor synthesis on plasma membranes
B)inhibition of sialic acid receptor synthesis on plasma membranes
C)mutation of sialic acid receptor sequence on plasma membranes
D)cleavage of sialic acid receptor proteins on plasma membranes
E)post-translational modification of sialic acid receptors

Question 42

Figure 8.11 provides evidence that this/these protein(s)possess hydrophobic regions: (Select all that apply)

A)VP4
B)VP1
C)PVR
D)All choices are correct
E)No choices are correct

Question 43

Baltimore's experiments to verify the existence of an RNA-dependent DNA polymerase required which of the following results in a viral replication assay? (Select all that apply)

A)Early addition of ribonuclease inhibited viral replication
B)Early addition of deoxyribonucease inhibited viral replication
C)Pre-incubation of virus and ribonuclease stimulated viral replication
D)Preincubation of virus and deoxyribonuclease inhibited viral replication
E)Late incubation of virus and deoxyribonuclease inhibited viral replication

Question 44

If an antiretroviral drug is designed to inhibit an enzyme required for the growth of the virus in an infected cell,which enzyme's inhibition is likely to be both effective and least toxic to the host cell?

A)RNA-dependent DNA polymerase
B)RNA-dependent RNA polymerase
C)DNA-dependent DNA polymerase
D)DNA dependent RNA polymerase
E)All would be equally effective and toxic

Question 45

Which of the following proteins would be found at the base of the tail fibers of a genetically modified PP01 bacteriophage which is now capable of infecting E.coli K12 cells? (Select all that apply. )

A)Gp37
B)Gp38
C)ompF
D)lipopolysaccharide
E)none of the choices is correct

Question 46

The detection of fluorescently labeled DNA fragments from infected and non-infected cells can result in fluorescent color patches which are: (Select all that apply. )

A)Red
B)Green
C)Yellow
D)Colorless
E)None is a correct choice

Question 47

The host specificity of a hepatitis virus may be determined by: (Select all that apply)

A)Liver detoxification enzymes found in the endoplasmic reticulum
B)The surface glycoproteins expressed on the hepatocyte surface
C)Proteins found in plasma membrane-associated transmembrane channels
D)Cytochromes within the liver mitochondria
E)Adhesion molecules maintaining liver tissue integrity

Question 48

Most non-enveloped viruses exit the cell by the following process

A)exocytosis.
B)budding.
C)Golgi transport.
D)cell lysis.
E)cytokinesis.

Question 49

An anti-influenza drug interacting with hemaglutinin (HA)could potentially act by (Select all that apply)

A)block viral binding to host cellreceptors
B)chemically modifying the viral binding protein
C)making antibody production unlikely to occur
D)reducing virion release from an infected cell
E)all choices are correct

Question 50

Which of the following observations provides evidence that a virus uses reverse transcriptase? (Select all that apply)

A)positive sense RNA is found within the host cell
B)actinomycin D prevents viral replication
C)heteroduplexes form when viral mRNA is added to infected host cell extracts
D)dsDNA strands form when cDNA is added to infected host cell extracts
E)inhibition of cellular DNA-dependent RNA polymerase has no effect on viral replication

Question 51

Fluorescent markers used in DNA microarray technology to label DNA fragments are which of the following colors? (Select all that apply. )

A)Red
B)Green
C)Yellow
D)Colorless
E)None is a correct choice

Question 52

Tamiflu resistance is a result of:

A)mutation in the hemaglutinin (Ha)encoding gene of the influenza virus
B)mutation of the neuraminidase (NA)encoding gene of the influenza virus
C)mutation in the hemaglutinin (NA)encoding gene of the influenza virus
D)mutation in the neuraminidase (HA)encoding gene of the influenza virus
E)none of these options is correct

Question 53

Bacteriophage T4 lyses the bacterial host cell for release of newly formed virions.The cell wall of the bacterium is broken down by this virally encoded enzyme

A)lysozyme.
B)protease.
C)β-lactamase.
D)nuclease.
E)peptidase.

Question 54

Proteins which must undergo a conformational change to allow HIV envelope fusion to occur include: (Select all that apply)

A)CD4 receptor
B)HIV gp 120
C)HIV gp41
D)Fusion peptide
E)Coreceptor

Question 55

Baltimore's experiments to verify the existence of an RNA-dependent DNA polymerase required which of the following results? (Select all that apply)

A)radiolabeled precipitate after a trichloroacetic acid treatment of viruses incubated with the reagents of a standard DNA polymerase assay
B)no radioactive precipitate after a trichloroacetic acid treatment of viruses incubated with the reagents of a standard DNA polymerase assay
C)ribonuclease sensitivity in precipitate created in the standard DNA polymerase assay
D)deoxyribonuclease sensitivity in precipitate created in the standard DNA polymerase assay
E)none of the coices is relevant

Question 56

The intact virion of the tobacco mosaic virus is assembled by this method

A)the capsid is first assembled and the nucleic acid is packaged into the capsid.
B)part of the capsid is assembled and the nucleic acid is packaged into the capsid.
C)the capsid proteins assemble around the viral nucleic acid.
D)the nucleic acid is inserted into the cell membrane and the capsid acquires the nucleic acid as it buds through the membrane,
E)the capsid is assembled in the cytoplasm and the nucleic acid is packaged in the nucleus.

Question 57

Translation of mRNA for the production of viral proteins always takes place in the cytoplasm of eukaryotic cells.

Question 58

Class VII viruses,double-stranded DNA viruses that utilize reverse transcriptase,replicate their genome using the following polymerase(s)(Select all that apply)

A)host cell DNA-dependent DNA polymerase.
B)viral DNA-dependent DNA polymerase.
C)viral DNA-dependent RNA polymerase.
D)viral RNA-dependent DNA polymerase.
E)host cell DNA-dependent RNA polymerase.

Question 59

Members of the poxviridae family replicate their genome through use of (Select all that apply)

A)host RNA-dependent RNA polymerase.
B)host DNA-dependent DNA polymerase.
C)virus-encoded RNA-dependent RNA polymerase.
D)virus-encoded DNA-dependent DNA polymerase.

Question 60

Most enveloped viruses exit the cell by the following process

A)exocytosis.
B)budding.
C)Golgi transport.
D)cell lysis.
E)cytokinesis.

Question 61

HIV enters the cell through a/an _________ mechanism.

A)phagocytic
B)receptor-mediated endocytotic
C)membrane fusion
D)acid-dependent endosomal
E)receptor-independent endocytotic

Question 62

Most enveloped viruses exit their host cell through a process called __________.

Question 63

Most enveloped viruses exit the host cell through cell lysis.

Question 64

A viral fusion peptide contains a short hydrophobic amino acid sequence that helps facilitate membrane fusion of the viral envelope to the cell membrane for entry into the host cell.The protein _____________ functions as a fusion peptide for HIV entry into the host cell.

Question 65

The information presented in section 8.4 suuports the theory that retroviruses produce RNA-dependent DNA polymerase after infection of a host cell.