Micbiology chapter 6

A prophage is a stage in the development of a/ an... A. Bacterial virus B. Poxvirus C. Lytic virus D. Envloped virus

A. Bacterial virus

Clear patches and so cultures that indicate sites of virus infections are called.... A. Plaques B. Pocks C. Colonies D. Prions

A. Plaques

The envelope of an animal virus is derived from the Peptolikein of its host cell. True or false

False

In lysogeny, viral DNA is inserted into the hosts chromosome. True or false

True

Viruses that persist in the (host) cell and cause recurrent diseases are called latent.

True

Most scientists do not consider viruses to be "alive" because: (a)They have no genes. (b)Their metabolic machinery is borrowed from the host cell. (c)They are unable to reproduce. (d)No definite structural features are seen under the microscope. (e)They are unable to evolve

b

Viruses cannot be cultivated in/ on.... A. Tissue culture B. Bird embryos C. Live mammals D. Blood agar

D. Blood agar

The nucleic acid of a virus is... A. DNA only B. RNA only C. Both DNA and RNA D. Either DNA or RNA

D. Either DNA or RNA

The nucleic acid of animal viruses enters the cell through a process called translocation. True or false

False

Bacterial viruses were first named _________ by _________ . a) bacteriophages, D'Herelle b) bacteriophages, Beijerinck c) microbes, D'Herelle d) microbes, Beijerinck

a) bacteriophages, D'Herelle

Nucleic acid genomes are isolated from Poliovirus, Influenza virus, and HIV. Each one is injected into mouse cells in separate experiments. Only the Poliovirus genome results in new virus particles being released from the cells. No new virions are released after injecting the Influenza or retrovirus genome. Why do you think this is the case? (a)Only Poliovirus can replicate in a human host cell. (b)The first event in the replication cycle of Influenza and retrovirus requires a viral protein. (c)Influenza and retrovirus are both (-) stranded RNA viruses. (d)The retrovirus and Influenza genomes were missing primers needed for replication. (e)Only Poliovirus uses host cell ribosomes for translation.

b

Intracellular structures formed during many viral infections, called __________, which can directly disrupt cell structure. a) Procaryotes b) Chromosomal disruptions c) Inclusion bodies d) Cytocidal bodies e) All of the above

c) Inclusion bodies

The size of viruses is usually measured in: a) Micrometers b) Decimeters c) Nanometers d) Millimeters

c) Nanometers

All the following are useful in the treatment of viruses except: a) Acyclovir b) Interferon c) Penicillin d) Antibodies

c) Penicillin

A _________ protein keeps the prophage dormant and prevents virus reproduction. a) Operator b) Promotor c) Repressor d) Inducer e) Enhancer

c) Repressor

The procapsid is assembled with the aid of _______ proteins. a) Ladder b) Framing c) Scaffolding d) Form e) None of the above

c) Scaffolding

In order for a virus to replicate: a) The capsid must enter the host cell cytoplasm b) The host cell must be undergoing mitosis c) The genome must be released in the cytoplasm d) The host cell must lack a cell membrane

c) The genome must be released in the cytoplasm

The filamentous bacteriopohage infect male E. coli cells by attaching to a) Lipopolysaccharide b) The cell wall c) The tip of the pilus d) The cell membrane e) The periplasmic space

c) The tip of the pilus

A structural property of HIV is _________ . a) it displays helical symmetry b) the genome is DNA c) it contains two molecules of reverse transcriptase d) it lacks a lipid - containing envelope e) it's diameter is around 50 nm

c) it contains two molecules of reverse transcriptase

Viroids are composed of a) single-stranded DNA b) double-stranded DNA c) single-stranded RNA d) double-stranded RNA e) DNA and RNA

c) single-stranded RNA

The general steps in a viral multiplication cycle are. A. Absorption, penetration, synthesis, assembly, and release B. Endocytosis, uncoding, replication, assembly, and budding C. Absorption, uncoding, duplication, assembly, and lysis D. Endocytosis, penetration, replication, mutation, and exocytosis

A. absorption, penetration, synthesis, assembly, and release

In general RNA viruses multiply in the cell _______, and DNA viruses multiply in the cell _______. A. Nucleus, cytoplasm B. Cytoplasm, nucleus C. Vesicles, ribosomes D. Endoplasmic reticulum, nucleolus

B Cytoplasm, nucleus

Viruses are known to infect.. A. Plants B. Bacteria C. Fungi D. All organisms

D. All organisms

A viral capsid is composed of subunits called virions. True or false

False

The _____ of the influenza-enveloped virus appear to be involved in attachment to the host cell receptor site. a) Pili b) Fimbriae c) Flagellae d) Hemagluttinin e) Neuraminidase

Hemagluttinin

Which of the following are viral infections: chlorea, rabies, plaques, cold sores, whooping cough, tetanus, genital warts, gonorrhea, mumps, Rocky Mountain spotted fever, syphilis, rubella

Rabies, cold sores, genital warts, mumps, rubella

Pick as many answers as necessary to correctly answer the question. The reservoir for Poliovirus is believed to be: (a)humans (b)pigs (c)rodents (d)birds (e)non-human primates

a

Reverse transcriptase is a useful enzyme to have when: a) An RNA virus converts its RNA to DNA b) There are no host cells present c) Nutrients are scarce d) Spikes are forming in the new virus

a) An RNA virus converts its RNA to DNA

Holes produced in bacterial "lawns" by viruses are called a) Colonies b) Plaques c) Patches d) Lysis e) Clearance

b) Plaques

Which two of the following statements with regards to the reproduction of animal viruses is TRUE? (a)When a virus attaches to a host cell, the viral genome is "injected" through the cell membrane into the cytoplasm. (b) The specificity of viruses for certain types of cells is usually explained by the virus receptors that it displays on its surface. (c)Negative strand ssRNA employ host RNA polymerase to synthesize mRNA. (d) Viruses often "trick" host cells by attaching to surface molecules that are normally taken in by endocytosis. (e)The replication of the genome of the virus only occurs in the intracellular state.

d e

In the Baltimore viral classification scheme, which two of the following criteria to categorize viruses? (a)The kind of nucleic acid (DNA or RNA) in the capsid. (b)The shape of the virus' capsid. (c)The size of the virus particle. (d)The presence or absence of an envelope. (e)The steps involved in the formation of viral mRNA after the virus has infected the cell.

a e

Which two of the following statements BEST describes all types of viruses that have an RNA genome? (a)They always contain a gene encoding an RNA-dependent RNA or DNA polymerase. (b)The viral genomes can always act as mRNA. (c)The virions of RNA viruses always contain an RNA-dependent RNA or DNA polymerase protein. (d)They are always single stranded. (e)They have higher mutation frequencies relative to viruses containing DNA genomes.

a e

A virus is a tiny infectious.... A. Cell B. Living thing C. Particle D. Nucleic acid

C. Particle

Viruses require ______ for growth. a) Plants b) Animals c) Bacteria d) Living cells e) Fungi

d) Living cells

A _______ is specifically able to have a long-term relationship with the host known as lysogeny. a) Temperate virus b) Adsorbed virus c) Viriond d) RNA phage e) DNA phage

a) Temperate virus

The most efficient way to enclose a space is within a a) Sphere b) Cube c) Icosahedron d) Helix e) None of the above

c) Icosahedron

Which of the following statements about viral capsids is FALSE? (a)Damage to one of the protein subunits of a virus capsid may destroy the infectivity of the virus particle. (b)One function of the outer shell (capsid) of a virus particle is to protect the virus genome from chemical damage. (c)The outer surface of the virus is responsible for recognition of the host cell. (d)One function of the outer shell (capsid) of a virus particle is to protect the virus genome from enzymatic damage. (e)One function of the outer shell (capsid) of a virus particle is to protect the virus genome from physical damage.

a

Which of the following statements regarding the adsorption of viruses is TRUE? (a)The process involves random collisions between the virus particle and the cell and is reversible. (b)The process requires energy from the hydrolysis of ATP. (c)Naked viruses could bind to the lipid bilayer of the host cells via exposed capsid regions. (d)There is a specific binding of a structure on the virus and a complementary structure on the host cell. (e)It describes the fusion of the cell membrane with the envelope of a virus.

a

Which one of the following statements about Poliovirus infections in humans is FALSE (a)The virus can remain latent for long periods of time. (b)Large amounts of virus are excreted from the body during infection. (c)The virus replicates in the gut. (d)The virus can infect cells of the central nervous system. (e)The virus enters the body through the mouth

a

For this question, pick as many answers as necessary to correctly answer the question. Which of the following statement(s) would correctly finish the statement. "Viruses _______________ " (a)are carriers of genetic information. (b)are obligate intracellular parasites. (c)all have lipid bilayer envelopes. (d)can replicate on their own. (e)can reproduce within a host cell. (f)utilize double-stranded DNA genomes at some point in their replication cycle.

a b e

Viral RNA is replicated in the host cell a) Cytoplasmic matrix b) Nucleus c) Wall d) Mitochondria e) Lysozomes

a) Cytoplasmic matrix

T-even phage binding to E. coli probably involves a) Electrostatic interaction b) Hydrophobic interaction c) Covalent bonds d) All of the above e) None of the above

a) Electrostatic interaction

Viruses can be purified based on their size and density by use of a) Gradient centrifugation b) Differential centrifugation c) Precipitation d) Filtration e) All of the above

a) Gradient centrifugation

With which of the following is virus always detectable after infections? a) Hepatitis B virus b) Herpes simplex virus c) Varicella-zoster virus d) Cytomegalovirus e) Epstein-Barr virus

a) Hepatitis B virus

When a virus enters a cell but does not replicate immediately, the situation is called: a) Lysogeny b) Fermentation c) Symbiosis d) Synergism

a) Lysogeny

Usually viruses are separated into several large groups based primarily on a) Nature of the host b) Nucleic acid characteristics c) Capsid symmetry d) Presence of an envelope and ether sensitivity e) Diameter of the viroin or nucleocapsid

a) Nature of the host

One of the first enzymes synthesized by many bacteriophage is __________ , an RNA-dependent RNA polymerase called a) RNA replicase b RNA transcriptase c) Reversetranscriptase d) RNA polymerase e) RNA ligase

a) RNA replicase

Which of the following is NOT a factor contributing to the occurrence of major pandemics of Influenza A virus? (a)Antibodies that bind to a specific hemagglutinin subtype (e.g., H1) do not bind to other hemagglutinin subtypes (e.g., H5). (b)Small changes in amino acid sequence within a given Influenza hemagglutinin subtype can alter the ability of antibodies to neutralize the virus. (c)The major reservoir for Influenza viruses is birds. (d)Influenza has a segmented genome. (e)Reassortment of influenza genome segments can take place in intermediate species, for example, pigs

b

Which of the following statements about Poliovirus replication cycle is CORRECT (a)The viral genome is replicated by the cellular RNA polymerase enzymes. (b)As the virus' polyprotein is synthesized, it folds and parts of the polyprotein become a functional protease and cleaves the polyprotein during and after its synthesis. (c)To compete with the cellular mRNA, the virus produces a protease which cleaves part of the cap binding complex of the cellular mRNA, and then uses it as a primer to make its own RNA. (d)As the virus' polyprotein is synthesized, it uses the host cell proteases to cleave it into the individual polypeptides. (e)The virus shuts off cellular protein synthesis by having the internal ribosome entry site (IRES) bind to the 5' methylated caps of the cellular mRNA.

b

Which one of the following hypothetical viruses cannot replicate successfully in a host cell? Assume the capsid proteins are encoded in all viruses' genomes, and if the virus can produce mRNA, it will be translated and the polyprotein will be cleaved properly. (a)The virus has a single stranded (-) DNA genome and replicates in the cytoplasm. It has a DNA and RNA polymerases packaged inside the capsid. (b)The virus has a single stranded (-) DNA genome and replicates in the cytoplasm. It has a DNA polymerase packaged inside the capsid, and its genome encodes an RNA polymerase enzyme. (c) The virus has a double stranded DNA genome and replicates in the host nucleus. (d)The virus has a single stranded (+) RNA genome and replicates in the cytoplasm of the cell. (e)The virus has a single stranded (-) RNA genome and replicates in the cytoplasm. It has an RNA dependent RNA polymerase enzyme packaged in its capsid.

b

Which one of the following statements about Poliovirus infections in humans is FALSE (a)A person that has vaccinated with IPV can be infected with Poliovirus if they ingest water contaminated with Poliovirus. (b)A person vaccinated with IPV will neutralize the Poliovirus in their gut. (c)Repeated vaccinations with either IPV and OPV may result in the presence of IgG antibodies in the blood. (d)A person vaccinated with OPV will shed the virus in their feces for a couple of weeks. (e)OPV mimics a natural infection with Poliovirus

b

In cancer, the reversion of cells to a more primitive or less differnetiated state is called a) Neoplasia b) Anaplasia c) Metastasis d) Oncogenic e) All of the above

b) Anaplasia

Which family has received most interest in their development as a biological control agent against insects? a) Reoviridae b) Baculoviridae c) Iridoviridae d) Poxviridae e) Rhabdoviridae

b) Baculoviridae

The most popular indirect method of counting virus particles is a) Microscopically b) By hemagglutination assay c) By plaque-assay d) By counting plaque-forming units e) By colony counting

b) By hemagglutination assay

The viruses in an attenuated vaccine: a) Have no genome b) Continue to replicate c) Are usually larger than bacteria d) Have been altered with chemicals

b) Continue to replicate

The researcher Stanley Prusiner is associated with work on: a) Kuru b) Prions c) Viroids d) Bacteriophages

b) Prions

A bacterial defense mechanism against bacteriophage is called a) Concatamerization b) Restriction c) Polymerization d) Lysogeny e) Lysis

b) Restriction

The hepadnaviruses such as hepatitis B virus are quite different from other DNA viruses with respect to genome replication. They replicate their DNA using a) DNA-dependent DNA polymerase b) Reverse transcriptase c) Rnase H d) RNA-dependent DNA polymerase e) DNA ligase

b) Reverse transcriptase

The conquest of the Aztec Empire in Mexico was made possible by a _____ epidemic that ravaged Mexico City. a) Measles b) Smallpox c) Rabies d) Influenza e) Chickenpox

b) Smallpox

The envelope of an enveloped virus is derived from: a) The mitochondrion of the cell b) The cell membrane c) The spikes of the cell d) The endoplasmic reticulum of the cell

b) The cell membrane

What is the best example of microevolution that we have? a) potato spindle tuber viroid b) colds and flu c) bacteria d) Epstein-Barr virus e) HIV causing cancer

b) colds and flu

Which features do viruses have in common with living cells? a) the ability to crystallized b) the ability to adapt and change c) the ability to reproduce by themselves d) the ability to metabolize e) none of the above

b) the ability to adapt and change

Eating meat from cattle with bovine spongiform encephalitis can cause a variant of _______ in humans. a) Kuru b) Fatal familial insomnia c) Creutzfeldt-Jakob disease d) Geistmann-Straussler-Scheinker syndrome e) Alzheimer's disease

c) Creutzfeldt-Jakob disease

Immunity to some viral diseases can be conferred with the use of attenuated virus vaccines. However, for some viral diseases, an attenuated vaccine would be regarded as too dangerous. Which statement describes the MOST SIGNIFICANT concern regarding attenuate virus vaccines? (a)Attenuated vaccines would induce only humoral immunity in the patient receiving them. (b)Because the virus is attenuated, the patient's immune system would not generate an immune response against it. (c)The attenuated virus might mutate as it is replicating in the patient and revert back to its virulent form. (d)An attenuated vaccine may not generate protective immunity because only a portion of the viral genome is used. (e)The vaccine would only be effective in people that are immunodeficient or immunocompromised; therefore it would not be useful for a large proportion of the general population

c

Most enveloped viruses obtain their envelopes by: (a)"stealing" and then modifying vesicles that may be used in the exporting of cellular proteins. (b)breaking down the membrane of the cell they infect and incorporating the lipid into the capsids. (c)budding through the cell's membrane as they leave an infected cell. (d)encoding an enzyme which synthesize the necessary lipids for the envelope. (e)finding pieces of cell membrane released from dead cells and wrapping it around them.

c

Reverse transcriptase (RT) is an enzyme found in retrovirus particles like HIV. Which of the following statements regarding RT is true? (a)RT is active and transcribing the viral RNA into DNA after the virus particle matures, and before it infects a new host cell. (b)RT used the 5' methylated cap of cellular mRNAs as a primer to make a DNA copy of the viral genome. (c)RT functions as RNase H to remove the RNA strand in a DNA/RNA hybrid. (d)RT transcribes the viral DNA after it is integrated into the host cell chromosome. (e)RT can function as a RNA dependent RNA polymerase

c

The Influenza vaccine is administered each year because: (a)the vaccine is designed to require frequent booster shots to maintain immunity and a continual source of income for the vaccine producers. (b)the vaccine is sufficiently toxic to make it necessary to administer only a small amount at any one time. (c)mutations and gene rearrangements in viral envelope protein genes may allow the virus to evade the immune response elicited by the previous vaccine. (d)it is a polysaccharide vaccine that does not confer long-term protection. (e)there are so many different serotypes of the virus that a single injection is not sufficient to elicit a full immune response.

c

The genome of rhabdoviruses consists of a single-stranded RNA molecule whose sequence is complementary to the RNA sequence which functions as a messenger RNA. How is the "+ sense" messenger RNA produced in cells infected by rhabdovirus? (a)the virus uses the host cell RNA polymerase to replicate its genome. (b)it uses reverse transcriptase to make DNA, then it uses the host cell RNA polymerase. (c)the infecting virus particle contains an RNA-dependent RNA polymerase. (d)the infecting RNA is directly translated by host cell ribosomes to produce the RNA dependent RNA polymerase (e)the RNA genome of the virus can be translated by the ribosomes if they read the RNA in a 3 ' to 5' direction

c

Which of the following most accurately describes a latent infection caused by a virus? (a)The virus replicates in the host and the host cell is usually killed by the release of the progeny viruses. (b)The virus genome has integrated into the host cell, and possibly transformed the cells into tumour cells. (c)The viral genome is inside the cell, but the genome is not replicating or the virus is not doing harm to the cell. (d)The virus replicates in the host cell, and slowly releases virus progeny with very few of the infected cells dying. (e)The viruses infects the host cells, produces a virus progeny, then completely stops and remains inactive

c

Which would be the first step in the biosynthesis of a virus that uses reverse transcriptase in its replication cycle? (a)Double-stranded RNA must be synthesized. (b)A complementary strand of RNA must be synthesized. (c)A complementary strand of DNA must be synthesized from an RNA template. (d)A complementary strand of DNA must be synthesized from a DNA template. (e)The RNA is first translated to produce the reverse transcriptase enzyme

c

Which two of the following statements about viruses are NOT TRUE (a)Viruses contain DNA or RNA. (b)The virus' nucleic acid is surrounded by a protein coat. (c)Viruses multiply inside living cells using viral mRNA, viral tRNA and viral ribosomes. (d)Viruses multiply inside dead cells. (e)Viruses can evolve to become more virulent

c d

Edward Jenner began inoculating humans with material from ______ lesions. a) Smallpox b) Avianpox c) Cowpox d) Chickenpox e) Dogpox

c) Cowpox

For an immature HIV particle to become an infectious particle, which of the following has to happen? (a)The virus has to reverse transcribe its RNA genome. (b)A viral encoded protease has to cleave the Env protein to form gp120 and gp41. (c)The gp120 has to undergo a conformational change, which then triggers a second conformational change in the gp120. (d)A viral encoded protease has to cleave specific sites in the Gag and Gag/Pol polyprotein. (e)Active reverse transcriptase and integrase in the mature virus has to cleave the Gag and Gag/Pol polyprotein.

d

For this question, pick as many answers as necessary to correctly answer the question. The ability of an animal virus to infect a cell depends primarily on: (a)whether or not the host cell has a nucleus. (b)the enzymatic activity of the host cell. (c)the type of viral nucleic acid. (d)presence of receptor sites on the cell membrane. (e)whether or not the cell is actively dividing.

d

Sialic acid (SA) is present on all cells of the human body, and can bind to the HA envelope protein of the Influenza virus. Why are most strains of Influenza typically a respiratory pathogen (in humans) and not a systemic (whole body) pathogen (a)The enzyme, Tryptase Clara, is found in the respiratory tract; this modifies HA to reveal the fusion peptide so that the virus envelope can fuse with the host cell plasma membrane. (b)The cilia in the respiratory tract "trap" the virus particles and facilitate its binding to the host cell. (c)The pH of the upper respiratory tract results in a conformational change in HA so that it can bind to the SA. (d)The enzyme, Tryptase Clara, is found in the respiratory tract; this modifies HA so that the fusion peptide can be revealed in an acidified endosome. (e)The Tryptase Clara actually modifies the SA on the respiratory cells so that the Influenza virus can bind to it

d

The products of the env gene: (a)are derived by proteolysis of a Gag-Pol-Env precursor protein. (b)are phosphoproteins. (c)are inserted into the viral envelope after the virus has budded through the cell membrane, and matured outside of the host cell. (d)of HIV are gp120 and gp41, with gp120 being able to bind to cells containing a CD4 surface receptor. (e)are translated after the ribosome has undergone a frame-shifting event

d

Which of the following is NOT TRUE about the Influenza virus HA protein? (a)it mediates attachment to target cells and the agglutination of red blood cells. (b)it must be cleaved by a host protease for the virus to be fully infective. (c)it catalyzes the fusion of the viral envelope with the endosomal membrane. (d)it cleaves the host cell sialic acid so that it can bind to the host cell. (e)it is a glycoprotein

d

Which of the following are obligate intracellular parasites? a) Viruses b) Chlamydia c) Rickettsia d) All of the above e) None of the above

d) All of the above

Which of the following is/are synthesized from late mRNA? a) Phage structural proteins b) Proteins that help with phage assembly without becoming part of the virion structure c) Proteins involved in cell lysis and phage release d) All of the above e) None of the above

d) All of the above

The viral nucleocapsid is the combination of: a) Capsomere and genome b) Capsid and spikes c) Envelope and capsid d) Genome and capsid

d) Genome and capsid

The oncogene theory refers to: a) How chemicals inactivate viruses when applied b) How viruses replicate in host cells c) Where viruses come from d) How viruses transform normal cells into tumor cells

d) How viruses transform normal cells into tumor cells

Which of the following has been linked to cervical cancer? a) Epstein-Barr virus b) Human T-cell lymphotropic virus c) Human immunodefficiency virus d) Human papilloma virus e) Human herpes virus 8

d) Human papilloma virus

The process by which phage reproduction is initiatied in lysogenized culture is called a) Infection b) Integration c) Repression d) Induction e) Enhancement

d) Induction

How would you best describe the shape of a helical virus? a) It is a regular polyhedron with 20 triangular faces and 12 corners. b) The capsomeres of each face form an equilateral triangle. c) It is spherical in shape. d) It resembles long rods that may be rigid or flexible. e) The virus is enclosed by an envelope.

d) It resembles long rods that may be rigid or flexible.

Which of the following is the agent associated with development of neurodegenrative disease in livestock and humans? a) Viroids b) virions c) Virinos d) Prions e) Viruses

d) Prions

Which is NOT true of virions? a) Contain DNA b) Contain RNA c) Are extracellular d) Reproduce independently e) Induce host metabolism

d) Reproduce independently

Enveloped viruses have a ______ shape. a) Icosahedral b) Helical c) Hexagonal d) Roughly spherical e) Complex

d) Roughly spherical

When PhiX174 DNA enters the host, it is immediately copied by the bacterial DNA polymerase to form a double-stranded DNA, which directs the synthesis of all BUT the following? a) More replicative form copies b) mRNA c) The +DNA genome d) The -DNA genome e) None of the above

d) The -DNA genome

The size of the smallest viruses can be said to be _____________ . a) approximately the size of small bacteria b) larger than 300 nm in diameter c) highly visible with a light microscope d) not much larger than the diameter of a double-stranded DNA helix e) none of the above

d) not much larger than the diameter of a double-stranded DNA helix

Since viruses are non-living until they enter a host, they are considered to be _________ . a) virions b) renegade cell parts c) opportunistic d) parasitic e) and d

d) parasitic

More support for the "protein only" hypothesis for prions has been supplied by studies on a prion found in a) humans b) cattle c) sheep d) yeast e) bacteria

d) yeast

A Poliovirus is constructed such that its genome is artificially modified; it loses all of the nucleic acid prior to the P2 (i.e, the 5' UTR and P1 which encodes structural proteins). The capsid of this mutated virus is structurally normal. When this mutated virus strain is used to infected susceptible host cells, what happens? (a)The virus genome will be replicated by the host cell RNA polymerase, but it won't be translated by the host cell ribosomes. (b)The virus genome will be replicated normally using the RDRP encoded by the genome, however, no virus progeny will be produced. (c)The virus would not be able to infect a cell. (d)The virus will replicate normally using the RDRP encoded by the genome and virus progeny will be produced. (e)The virus can infect a cell, but it won't be able to replicate its genome. Therefore, no progeny will be produced

e

For safety reasons, which of the following is the least likely vaccine against HIV? (a)Purified Gag/Pol polyprotein (b)Purified Gag polyprotein. (c)Viral glycoproteins (such as purified gp120 or gp41). (d)The virus' capsid proteins. (e)Attenuated virus

e

One strain of influenza virus that infects mammals undergoes mutation such that the HA glycoprotein no longer requires the modification by Tryptase Clara. Which is likely to be the result of this mutation? (a)The virus would still require Trypase Clara, since it is also needed to release the viral genome into the cytoplasm. (b)The virus would no longer need to have the pH-dependent of modification of HA since the envelope could fuse with the host cell plasma membrane. (c)The influenza vaccines would be ineffective, since they induce antibodies that bind to form of HA before it is modified by Tryptase Clara. (d)The virus would no longer need its NA enzyme to release from the host cells; thus, the NA inhibitor drugs would be ineffective in treating influenza infections. (e)The virus would have increased virulence since it is now able to infect cells of the body beyond the respiratory tract

e

Which of the following statements about Influenza virus is TRUE (a)Influenza virus must integrate into the host chromosome to replicate and produce new virus particles. (b)Influenza infection kills the host cell when it lyses to release the viral progeny. (c)Influenza virus mRNA is actually (-) stranded (negative sense). (d)Host cell RNA polymerase produces mRNA used for protein synthesis. (e)Antigenic drift is the term applied to minor antigen ic changes due to genetic variations such as point mutations

e

Which of the following statements concerning HIV therapy and/or vaccination is CORRECT (a)The combination of reverse transcriptase and protease inhibitors now in use will completely eliminate the HIV provirus from all parts of the body. (b)Vaccines against the reverse transcriptase and integrase proteins would be effective against HIV infection. (c)Immunizing an HIV-positive patient with purified gp120 will induce the production of antibodies that will prevent the virus from spreading to other cells. (d)Drugs used to inhibit the NA of the influenza virus would also prevent HIV from spreading from cell to cell. (e)Once HIV has integrated into the host chromosome, reverse transcriptase inhibitors such as AZT have no effect on virus replication within that cell

e

The word virus comes from the Latin meaning word meaning ________ ? a) "invisible" b) "tiny" c) "microscopic" d) "disease" e) "poison"

e) "poison"

Plant viruses may be cultivated in a) Tissue culture b) Cultures of separated cells c) Cultures of protoplants d) Whole plants e) All of the above

e) All of the above

Which of the following may affect proteins and nucleic acids, but NOT viruses? a) Denaturation b) Enzyme treatment c) Heat d) Drastic pH changes e) All of the above

e) All of the above

What kind of embryo is often used for viral assays? a) Mouse b) Rat c) Cat d) Dog e) Chicken

e) Chicken

Virulent and nonvirulent viruses may do any of the following but NOT a) Inhibit host cell DNA synthesis b) Inhibit host cell RNA synthesis c) Inhibit host cell protein synthesis d) Stimulate host cell macromolecule synthesis e) Degrade host cell DNA

e) Degrade host cell DNA

Which of the following has been linked to Kaposi's sarcoma? a) Epstein-Barr virus b) Human T-cell lymphotropic virus c) Human immunodefficiency virus d) Human papilloma virus e) Human herpes virus 8

e) Human herpes virus 8

A specific ______ factor helps RNA polymerase bind to late promoters and transcribe late genes. a) Alpha b) Beta c) Delta d) Gamma e) Sigma

e) Sigma

How would you best describe the shape of an icosahedral virus? a) It is a regular polyhedron with 20 triangular faces and 12 corners. b) The capsomeres of each face form an equilateral triangle. c) It is spherical in shape. d) It resembles long rods that may be rigid or flexible. e) a and b

e) a and b

Which of the following is NOT a characteristic of a virus? a) relies on a host-cell metabolism b) has a nucleic acid core surrounded by protein c) contains only one or a few enzymes d) relies on the hosts' reproductive capabilities to spread e) contains both DNA and RNA

e) contains both DNA and RNA

For this question, pick as many answers as necessary to correctly answer the question. A "permissive" viral infection always results in which of the following outcomes? (a)Inhibition of cellular protein synthesis. (b)Transformation of the host cell into a tumour cell. (c)Inhibition of cellular DNA replication. (d)Integration of the viral genome into the host cell genome. (e)Death of the host cell. (f)Production of progeny virus.

f