Basic Virology
182. Each of the following statements concerning lysogeny is correct EXCEPT: (A) Viral genes replicate independently of bacterial genes. (B) Viral genes responsible for lysis are repressed. (C) Viral DNA is integrated into bacterial DNA. (D) Some lysogenic bacteriophages encode toxins that cause human disease.
A
185. Each of the following viruses possesses an RNA polymerase in the virion EXCEPT: (A) Hepatitis A virus (B) Smallpox virus (C) Mumps virus (D) Rotavirus
A
187. Each of the following viruses possesses double-stranded nucleic acid as its genome EXCEPT: (A) Coxsackie virus (B) Herpes simplex virus (C) Rotavirus (D) Adenovirus
A
198. Main site of action of amantadine (A) Attachment and penetration of virion (B) Viral mRNA synthesis (C) Viral protein synthesis (D) Viral genome DNA synthesis (E) Assembly and release of progeny virus
A
200. Main site of action of antiviral antibody(A) Attachment and penetration of virion (B) Viral mRNA synthesis (C) Viral protein synthesis (D) Viral genome DNA synthesis (E) Assembly and release of progeny virus
A
203. The translation product of viral mRNA is a polyprotein that is cleaved to form virion structural proteins. (A) Poliovirus (B) Epstein-Barr virus (C) Prions (D) Hepatitis B virus (E) Respiratory syncytial virus
A
210. Nonenveloped RNA virus that is transmitted by the fecal-oral route (A) Hepatitis A virus (B) Hepatitis B virus (C) Hepatitis C virus (D) Hepatitis D virus
A
DIRECTIONS (Questions 193-211): Select the one lettered option that is MOST CLOSELY associated with the numbered items. Each lettered option may be selected once, more than once, or not at all. Questions 193-196 193. Herpes simplex virus (A) DNA enveloped virus (B) DNA nonenveloped virus (C) RNA enveloped virus (D) RNA nonenveloped virus
A
168. A temperate bacteriophage has been induced from a new pathogenic strain of Escherichia coli that produces a toxin. Which one of the following is the MOST convincing way to show that the phage encodes the toxin? (A) Carry out conjugation of the pathogenic strain with a nonpathogenic strain. (B) Infect an experimental animal with the phage. (C) Lysogenize a nonpathogenic strain with the phage. (D) Look for transposable elements in the phage DNA.
C
172. Each of the following statements concerning viral surface proteins is correct EXCEPT: (A) They elicit antibody that neutralizes infectivity of the virus. (B) They determine the species specificity of the virus-cell interaction. (C) They participate in active transport of nutrients across the viral envelope membrane. (D) They protect the genetic material against nucleases.
C
173. Each of the following statements concerning viral vaccines is correct EXCEPT: (A) In live, attenuated vaccines, the virus has lost its ability to cause disease but has retained its ability to induce neutralizing antibody. (B) In live, attenuated vaccines, the possibility of reversion to virulence is of concern. (C) With inactivated vaccines, IgA mucosal immunity is usually induced. (D) With inactivated vaccines, protective immunity is due mainly to the production of IgG.
C
175. The feature of the influenza virus genome that contributes MOST to the antigenic variation of the virus is: (A) A high G + C content, which augments binding to nucleoproteins (B) Inverted repeat regions, which create "sticky ends" (C) Segmented nucleic acid (D) Unique methylated bases
C
181. Viruses are obligate intracellular parasites. Each of the following statements concerning this fact is correct EXCEPT: (A) Viruses cannot generate energy outside of cells. (B) Viruses cannot synthesize proteins outside of cells. (C) Viruses must degrade host cell DNA in order to obtain nucleotides. (D) Enveloped viruses require host cell membranes to obtain their envelopes.
C
186. Each of the following viruses possesses a DNA polymerase in the virion EXCEPT: (A) Human immunodeficiency virus (B) Human T-cell lymphotropic virus (C) Epstein-Barr virus (D) Hepatitis B virus
C
191. Each of the following statements about both poliovirus and rhinoviruses is correct EXCEPT: (A) They are nonenveloped RNA viruses. (B) They have multiple antigenic types. (C) Their virions contain an RNA polymerase. (D) They do not integrate their genome into host cell DNA.
C
194. Human T-cell lymphotropic virus (A) DNA enveloped virus (B) DNA nonenveloped virus (C) RNA enveloped virus (D) RNA nonenveloped virus
C
204. It is remarkably resistant to ultraviolet light.(A) Poliovirus (B) Epstein-Barr virus (C) Prions (D) Hepatitis B virus (E) Respiratory syncytial virus
C
209. Enveloped RNA virus that is the most common cause of non-A, non-B hepatitis (A) Hepatitis A virus (B) Hepatitis B virus (C) Hepatitis C virus (D) Hepatitis D virus
C
180. Each of the following statements concerning viruses is correct EXCEPT: (A) Viruses can reproduce only within cells. (B) The proteins on the surface of the virus mediate the entry of the virus into host cells. (C) Neutralizing antibody is directed against proteins on the surface of the virus. (D) Viruses replicate by binary fission.
D
184. Which one of the following viruses possesses a genome of single-stranded RNA that is infectious when purified? (A) Influenza virus (B) Rotavirus (C) Measles virus (D) Poliovirus
D
190. Each of the following statements about both influenza virus and rabies virus is correct EXCEPT: (A) They are enveloped RNA viruses. (B) Their virions contain an RNA polymerase. (C) A killed vaccine is available for both viruses. (D) They each have a single antigenic type.
D
192. Each of the following statements about human immunodeficiency virus (HIV) is correct EXCEPT: (A) HIV is an enveloped RNA virus. (B) The virion contains an RNA-dependent DNA polymerase. (C) A DNA copy of the HIV genome integrates into host cell DNA. (D) Acyclovir inhibits HIV replication.
D
196. Rotavirus (A) DNA enveloped virus (B) DNA nonenveloped virus (C) RNA enveloped virus (D) RNA nonenveloped virus
D
197. Main site of action of acyclovir (A) Attachment and penetration of virion (B) Viral mRNA synthesis (C) Viral protein synthesis (D) Viral genome DNA synthesis (E) Assembly and release of progeny virus
D
202. Part of the genome DNA is synthesized by the virion polymerase. (A) Poliovirus (B) Epstein-Barr virus (C) Prions (D) Hepatitis B virus (E) Respiratory syncytial virus
D
208. Enveloped RNA virus that has the surface antigen of another virus (A) Hepatitis A virus (B) Hepatitis B virus (C) Hepatitis C virus (D) Hepatitis D virus
D
178. Each of the following statements concerning the viruses that infect humans is correct EXCEPT: (A) Only viruses with a negative polarity RNA genome have a polymerase in the virion. (B) The purified nucleic acid of some viruses is infectious, but at a lower efficiency than the intact virions. (C) Some viruses contain lipoprotein envelopes derived from the plasma membrane of the host cell. (D) The nucleic acid of some viruses is single-stranded DNA and that of others is double-stranded RNA.
A
165. Which one of the following forms of immunity to viruses would be LEAST likely to be lifelong? (A) Passive immunity (B) Passive-active immunity (C) Active immunity (D) Cell-mediated immunity
A
170. A stock of virus particles has been found by electron microscopy to contain 108 particles/mL, but a plaque assay reveals only 105 plaque-forming units/mL. The BEST interpretation of these results is that: (A) Only one particle in 1000 is infectious. (B) A nonpermissive cell line was used for the plaque assay. (C) Several kinds of viruses were present in the stock. (D) The virus is a temperature-sensitive mutant.
A
162. Latency is an outcome particularly characteristic of which one of the following virus groups? (A) Polioviruses (B) Herpesviruses (C) Rhinoviruses (D) Influenza viruses
B
166. Which one of the following statements concerning alpha, beta, and gamma interferons is LEAST accurate? (A) Interferons inhibit a broad range of viruses, not just the virus that induced the interferon. (B) Interferons are synthesized only by virus-infected cells. (C) Interferons induce the synthesis of a protein kinase that phosphorylates an elongation factor, thereby inactivating protein synthesis. (D) Interferons induce the synthesis of a ribonuclease that degrades viral mRNA.
B
169. Each of the following statements concerning retroviruses is correct EXCEPT: (A) The virion carries an RNA-directed DNA polymerase encoded by the viral genome. (B) The viral genome consists of three segments of double-stranded RNA. (C) The virion is enveloped and enters cells via an interaction with specific receptors on the host cell. (D) During infection, the virus synthesizes a DNA copy of its RNA, and this DNA becomes covalently integrated into host cell DNA.
B
171. Reasonable mechanisms for viral persistence in infected individuals include all of the following EXCEPT: (A) Generation of defective-interfering particles (B) Virus-mediated inhibition of host DNA synthesis (C) Integration of a provirus into the genome of the host (D) Host tolerance to viral antigens
B
174. The major barrier to the control of rhinovirus upper respiratory infections by immunization is: (A) The poor local and systemic immune response to these viruses (B) The large number of serotypes of the rhinoviruses (C) The side effects of the vaccine (D) The inability to grow the viruses in cell culture
B
176. Which one of the following is the BEST explanation for the selective action of acyclovir (acycloguanosine) in herpes simplex virus (HSV)-infected cells? (A) Acyclovir binds specifically to viral receptors only on the surface of the HSV-infected cell. (B) Acyclovir is phosphorylated by a virus-encoded phosphokinase only within HSVinfected cells. (C) Acyclovir selectively inhibits the RNA polymerase in the HSV virion. (D) Acyclovir specifically blocks the matrix protein of HSV, thereby preventing release of progeny HSV.
B
183. Each of the following viruses possesses an outer envelope of lipoprotein EXCEPT: (A) Varicella-zoster virus (B) Papillomavirus (C) Influenza virus (D) Human immunodeficiency virus
B
188. Regarding viroids, which one of the following statements is the MOST accurate? (A) They are defective viruses that are missing the DNA coding for the matrix protein. (B) They consist of RNA without a protein or lipoprotein outer coat. (C) They cause tumors in experimental animals. (D) They require an RNA polymerase in the particle for replication to occur.
B
189. Each of the following statements about both measles virus and rubella virus is correct EXCEPT: (A) They are RNA enveloped viruses. (B) Their virions contain an RNA polymerase. (C) They have a single antigenic type. (D) They are transmitted by respiratory aerosol.
B
195. Human papillomavirus (A) DNA enveloped virus (B) DNA nonenveloped virus (C) RNA enveloped virus (D) RNA nonenveloped virus
B
199. Function of virion polymerase of influenza virus(A) Attachment and penetration of virion (B) Viral mRNA synthesis (C) Viral protein synthesis (D) Viral genome DNA synthesis (E) Assembly and release of progeny virus
B
205. It causes latent infection of B cells.(A) Poliovirus (B) Epstein-Barr virus (C) Prions (D) Hepatitis B virus (E) Respiratory syncytial virus
B
207. Enveloped DNA virus that is transmitted by blood (A) Hepatitis A virus (B) Hepatitis B virus (C) Hepatitis C virus (D) Hepatitis D virus
B
211. Purified surface protein of this virus is the immunogen in a vaccine. (A) Hepatitis A virus (B) Hepatitis B virus (C) Hepatitis C virus (D) Hepatitis D virus
B
DIRECTIONS (Questions 159-192): Select the ONE lettered answer that is BEST in each question. 159. Viruses enter cells by adsorbing to specific sites on the outer membrane of cells. Each of the following statements regarding this event is correct EXCEPT: (A) The interaction determines the specific target organs for infection. (B) The interaction determines whether the purified genome of a virus is infectious. (C) The interaction can be prevented by neutralizing antibody. (D) If the sites are occupied, interference with virus infection occurs.
B
161. Biochemical analysis of a virus reveals the genome to be composed of eight unequally sized pieces of single-stranded RNA, each of which is complementary to viral mRNA in infected cells. Which one of the following statements is UNLIKELY to be correct? (A) Different proteins are encoded by each segment of the viral genome. (B) The virus particle contains a virus-encoded enzyme that can copy the genome into its complement. (C) Purified RNA extracted from the virus particle is infectious. (D) The virus can acquire new antigens via reassortment of its RNA segments.
C
160. Many viruses mature by budding through the outer membrane of the host cell. Each of the following statements regarding these viruses is correct EXCEPT: (A) Some of these viruses cause multinucleated giant cell formation. (B) Some new viral antigens appear on the surface of the host cell. (C) Some of these viruses contain host cell lipids. (D) Some of these viruses do not have an envelope.
D
163. Each of the following statements concerning viral serotypes is correct EXCEPT: (A) In naked nucleocapsid viruses, the serotype is usually determined by the outer capsid proteins. (B) In enveloped viruses, the serotype is usually determined by the outer envelope proteins, especially the spike proteins. (C) Some viruses have multiple serotypes. (D) Some viruses have an RNA polymerase that determines the serotype.
D
164. The ability of a virus to produce disease can result from a variety of mechanisms. Which one of the following mechanisms is LEAST likely? (A) Cytopathic effect in infected cells (B) Malignant transformation of infected cells (C) Immune response to virus-induced antigens on the surface of infected cells (D) Production of an exotoxin that activates adenylate cyclase
D
167. You have isolated a virus from the stool of a patient with diarrhea and shown that its genome is composed of multiple pieces of double-stranded RNA. Which one of the following is LEAST LIKELY to be true? (A) Each piece of RNA encodes a different protein. (B) The virus encodes an RNA-directed RNA polymerase. (C) The virion contains an RNA polymerase. (D) The genome integrates into the host chromosome.
D
177. Each of the following statements concerning interferon is correct EXCEPT: (A) Interferon inhibits the growth of both DNA and RNA viruses. (B) Interferon is induced by double-stranded RNA. (C) Interferon made by cells of one species acts more effectively in the cells of that species than in the cells of other species. (D) Interferon acts by preventing viruses from entering the cell.
D
179. Which one of the following statements about virion structure and assembly is CORRECT? (A) Most viruses acquire surface glycoproteins by budding through the nuclear membrane. (B) Helical nucleocapsids are found primarily in DNA viruses. (C) The symmetry of virus particles prevents inclusion of any nonstructural proteins, such as enzymes. (D) Enveloped viruses use a matrix protein to mediate interactions between viral glycoproteins in the plasma membrane and structural proteins in the nucleocapsid.
D
201. Step at which budding occurs(A) Attachment and penetration of virion (B) Viral mRNA synthesis (C) Viral protein synthesis (D) Viral genome DNA synthesis (E) Assembly and release of progeny virus
E
206. An envelope protein induces the formation of giant cells. (A) Poliovirus (B) Epstein-Barr virus (C) Prions (D) Hepatitis B virus (E) Respiratory syncytial virus
E
