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108 Cards in this Set
- Front
- Back
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Positive-strand RNA viruses differ from negative-strand RNA viruses in that the positive-strand viruses:
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contain infectious RNA
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Which of the following distinctive features of ciruses is incorrectly stated?
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Viruses provide their own ribosomes for protein synthesis and energy producing systems for replication
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Orthomyxoviruses and paramyxoviruses are correctly described as?
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enveloped helical viruses
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All of the following viral families have icosahedral (cubic) symmetry except
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Rhabdoviridae
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Which statement most closely applies to genetic reassortment as it occurs in viruses?
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A genetic interaction of principal importance to viral families with segmented genomes
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Which statement is not true for herpes simplex?
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replicates only in human cells
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Infection by varicella zoster virus
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may result in more than one clinical syndrome (disease)
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Which virus commonly infects B lymphocytes?
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EBV
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Which virus remains latent in tissue other than nervous tissue?
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EBV
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Which virus is a common cause of a sexually transmitted disease?
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herpes simplex type 2
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Which one of the following viruses is most commonly associated with serious birth defects?
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Cytomegalovirus
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Which DNA virus listed below possesses fibers or spikes projecting out from each of the 12 pentons?
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Adenoviruses
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Which syndrome is not associated with adenovirus infection?
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Heterophile-negative mononucleosis
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Which virus-disease relationship is incorrectly stated?
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Measles - birth-defects
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Laryngotracheitis (croup) in infants and young children is associated with which virus?
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Parainfluenza 1
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Subacute sclerosing panencephalitis is a progressive neurologic disease that occurs in individuals previously infected with
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Measles (rubeola) virus
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Which of the following viruses are the most frequent etiologic agents of common colds
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rhinoviruses
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All of the following are typical manifestations of type A, rather than type B, coxsackieviruses except
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pleurodynia (Bornholm disease)
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The immune response elicited by the Salk inactivated polio vaccine is deficient in specific
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Duodenal secretory IgA
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The presence of IgG but not IgM antibodies to rubella virus in the newborn suggests
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presence of maternal antibodies
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which agent is a major cause of nonbacterial infantile diarhea?
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rotavirus
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Which of the following is not true of the agent causing CJD?
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susceptible to formaldehyde
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Which organism is considered to be sexually transmitted?
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ureaplasma urealyticum
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All of the following viruses have capsids that are stable in acid EXCEPT
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Rhinoviruses
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All of the following statements about poliovirus infections are true except
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The Salk vaccine protects individuals against infection, alimentary tract replication of virus, and paralysis
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Which of the following viruses exists in nature in multiple antigenic forms or serotypes?
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parainfluenza virus
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Hemagglutinin is associated with which one of the following viruses
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influenza virus
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The presence of glycogen-containing inclusions is characteristic of infections with
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Chlamydia tradhomatis
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Viripexis is a term used by virologists to describe
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Cell entry of a virus by receptor-mediated endocytosis
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Which of the following require that a virus preparation be infectious to obtain a positive reaction?
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plaque assay
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Concerning DNA vs RNA viruses, in which group do most of the viruses use host cell polymerase to produce viral mRNA?
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DNA
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A unique feature of retroviruses that distinguish them from other RNA viruses is
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double-stranded genome
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With respect to the classification of RNA viruses, the following viruses are matched with a virion structure (cubic or helical, enveloped or naked), which is mismatched?
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paramyxoviruses - helical, naked
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An infectious virus particle must contain
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Capsid proteins
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Viral growth in susceptible tissue cell cultures can be detected in all of the following ways except
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the infected cells can absorb RBCs
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Which of the following specimens would not be useful for the isolation of enteroviruses?
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urine
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Subacute spongiform encephalopathies (e.g., Kuru, Scrapie, etc.) are a group of progressive degenerative neurological diseases that are caused by unconventional viruses. These viruses have a number of common proporties which include all of the following except
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small virion-like structures have been visualized by electron microscopy
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Which HIVE gene codes for a glycoprotein that is responsible for the host range of the virus and its antigenicity?
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env
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Which of the following retroviruses causes adult lymphocytic leukemia?
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HTLV-1
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Which of the following enveloped, single-stranded RNA viruses is not responsible for hemorrhagic fever?
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Bunyavirus
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Which of the following has not been associated with acute viral gastroenteritis?
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Enterovirus
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Which of the following is not a characteristic of acute viral gastroenteritis?
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primarily diseases of infants and children under 2 years of age
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Which of the following syndromes is not known to be associated with CMV infections in normal adults?
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pancreatitis
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In which of the following members of herpes viruses are leukocytes the site of latent infection?
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CMV
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Cold sores caused by
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herpes type 1
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Which of the following is not a member of the human herpesvirus group?
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papilloma virus
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Concerning hepatitis viruses, which of the following contains a dsDNA genome?
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HepB Virus
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Which of the following is not a member of the human enteroviruses?
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Coxsackievirus
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Which of the following statements about rubella is true?
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Deafness in a 4-y/o child may be the consequence of in-utero rubella infection
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Which of the following is not a clinical symptom caused by the mumps virus?
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Keratoconjunctivitis
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After F+ bacteria (F- factor not integrated into the chromosome) mate with F-- bacteria, the F-- bacteria usually become
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F+
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Which type of genetic transfer in bacteria require direct union?
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conjugation
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The following list refers to mechanisms of genetic transfer in bacteria. In which is transfer inhibited by deoxyribonuclease in the media?
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A. Transformation
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The following list refers to mechanisms of genetic transfer in bacteria.Which requires the presence of a plasmid in one of the participants?
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Transduction
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In addition to genetic transfer mechanisms, bacterial variation can occur by DNA rearrangements. These are controlled by recombination events such as the «cassette» model in which new genes are inserted into an expression site; or by the «flip-flop» model which involves revertible DNA elements. All except one of the following bacterial variations are known to occur by these mechanisms. Which is the
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Variation in M proteins in S. pyogenes
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A strain of enterotoxigenic E. coli was isolated from the stool of a patient suffering from «Travelerʼs Diarrhea». This strain was found to be resistant to four different antibiotics (tetracycline, chloramphenicol, ampicillin, and streptomycin). Such multiple resistance is often due to:
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Acquisition of extra chromosomal elements carrying different genes, each conferring resistance to a
different drug |
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Transposons differ from plasmids in that transposons
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Are not capable of self replication
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Which of the following is not a bacterial adhesin that allows attachment to epithelial cells?
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Glycoprotein
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Which of the following is not involved in the killing of bacteria by phagocytes?
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flavoproteins
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Facultative intracellular pathogens (FIP) are able to survive and multiply in phagocytes. Which one of the following is not a mechanism by which this is accomplished?
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Acquisition of a host derived protective coating
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Facultative intracellular pathogens (FIP) are able to survive and multiply in phagocytes. Which one of the following organisms are not members of this class?
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Haemophilus influenzae
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A purified protein derivative (PPD) of the tubercle bacillus has a marked toxic effect when injected into an animal that had been infected with the living organisms. Injection into a normal animal auses no reaction. This marked difference in reactivity is due to:
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Delayed-type hypersensitivity
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Loss of virulence in a bacterial pathogen is often due to
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loss of an antiphagocytic surface component
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S. aureus produces a substance, protein A, which has antiphagocytic properties. This substance prevents opsonization of Klebsellia by specific antibodies directed against the klebsiella capsule. This can be explained by the fact that protein A
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binds with the Fc portion of the opsonins, thus preventing its attachment to the phagocytes
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The toxicity of bacterial exotoxins...
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can be manifested in tissues that do not harbor the bacteria
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Bacterial exotoxins have been found that owe their activity to the ability to facilitate ADP-ribosylation of proteins. Which one of the following toxins does not fall into this class?
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botulin toxin
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Bacterial exotoxins have been found that owe their activity to the overproduction of cAMP. Which one of the following does not fall into this class?
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Diphteria toxin
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Which of the following extracellular products of pathogenic bacteria is a true toxin in that it has cytolytic activity?
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Lecithinase
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Endotoxin produced by Gram-negative bacteria can cause all of the following except
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delayed-hypersensitivity
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The pyrogenic activity of endotoxins is due to
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release of pyrogenic interleukins from macrophages
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Which of the following acts by directly blocking DNA replication?
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quinolone
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Which of the following inhibits protein synthesis by binding with bacterial ribosomal proteins?
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an aminoglycoside
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Which of the following prevents murein synthesis by inhibiting transpeptidase activity?
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beta-lactam antibiotic
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Many of the commonly used antibiotics directly inhibit cell wall syntehsus or protein synthesis. Which of the following does not?
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Rifampicin (inhibits nucleic acid synthesis)
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Which doesn't belowing in the following list?
a. Penicillins b. Carbapenams c. Aminoglycosides d. Monobactams e. Cephalosporins |
C. Aminoglycosides
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S. pyogenes is notorious for its production of a number and variety of biologically active extracellular metabolites. With respect to this, which of the following does not belong in the list?
a. Exfoliatin b. Fibrinolysin c. Hyaluronidase d. Erythrogenic toxin e. Deoxyribonuclease |
a. Exfoliatin
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Lipoteichoic acid is a surface structural component of S. pyogenes which contribute to the cirulence of streptococci. In which of the following ways does it do this?
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serves as a ligand to mediate binding to host cells via a fibronectin receptor
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Diphteria toxin consists of two major polypeptide subunits, A and B. All of the following are true except
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polypeptide A activates adenylyl cyclase
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A statistical analysis of the incidence of tetanus by age groups in the US showed that more than 60% of the cases occurred in people over 50 years of age. Which of the following would be the most probably explanation for this apparent disparity?
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The older people have lower immunity to the toxin because of incomplete or neglectful immunization regimes
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All of the following statements concerning Bacteroides fragilis are correct except
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Like all anaerobes, it is a spore-former which allows it to survive in the soil
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A city of 60,000 population in the midwestern USA reported the following number of cases over a one year period:
Diphteria - 1 Salmonellosis - 34 Infant botulism - 5 Brucellosis - 17 The incidence of diphteria probably resulted from... |
Natural and artifically acquired active immunity in the population
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During the first week of typhoid infection, which of the following sources would it be most likely to obtain a positive culture?
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blood
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Which of the following is zoonotic in origin?
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Salmonella
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With respect to intestinal infections caused by E.coli, which of the following types of E-coli produces stools which contain blood and pus
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enteroinvasive (EIEC)
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Yersinia enterocolitica has been implicated in the etiology of which of the following diseases?
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Mesenteric adenitis
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Which of the following inhibits the release of acetylcholine?
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botulin toxin
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The clinical syndrome described below can be caused by a bacterial exotoxin. Match the clinical syndrome with the organism that produces the toxin.
Diplopia, urinary retention, ptosis, respiratory distress |
Clostridium botulinum
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The clinical syndrome described below can be caused by a bacterial exotoxin. Match the clinical syndrome with the organism that produces the toxin.
Rash, fever, diarrhea, myalgia, hypotension |
S. aureus
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A sputum specimen from a cystic fibrosis patient who is showing signs of pneumonia was plated onto blood agar and incubated aerobically. When examined 24hrs later, the plate had a greenish pigmentation and large, mucoid colonies predominated. Gram stain showed gram-negative rods. Lactose fermentation was negative, but an oxidase test was positive. Which of the following is the most likely cause of the pneumonia?
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Pseudomonas aeruginosa
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Haemophilus influenzae type B is a major cause of a variety of infections in young children. Which of the following infections is not one of them?
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Endocarditis
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Which of the following can cause nongonococceal, nonchlamydial urethritis in men and chorioamnionitis in women?
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Ureaplasma urealyticum
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Which of the following statements do not apply to legionella?
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Legionella infections can be readily transmitted by person-to-person contact
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With respect to Lyme disease, which of the following is mismatched?
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Diagnosis - Dark field examination of primary lesion
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A 45-y/o farmer from Illinois presents with a history of intermittent fever, weight loss, malaise, and productive cough. CXR show a right lobe infiltrate. The PPD test is weakly positive and acid-fast bacilli are found in the sputum. Sputum culture on Lowenstein-Jensen medium shows growth after 3 weeks. The colonies are bright yellow-orange when grown in the light, but creamy colored in the dark. These findings strongly suggest a cavitary pulmonary disease caused by
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Mycobacterium kansasii
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With respect to the family Actinomycetales, which of the following will not grow in ordinary aerobic growth cultures?
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Actinomyces
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A bacterium that produces a toxin that has exactly the same molecular mechanism as the diphteria toxin is
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Pseudomonas aeruginosa
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Anaerobic bacteria are not part of the resident normal flora of which region of the human body?
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Esophagus
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The DTP vaccine is composed of which of the following?
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Diphteria toxoid
Tetanus toxoid heat-killed Bordetella Pertussis |
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The capsule of Bacillus anthracis is composed of
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d-glutamatic acid
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Listeria monocytogenes has all of the following charateristics except
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It is a spore former
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The most important antiphagocytic structure of the group A streptococci0 (S. pyogenes) is the
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M protein
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The toxin produced by S. aureus that is responsible for the staphylococcal scalded skin
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Exfolatin
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The streptococcus most commonly associated with subacute bacterial endocarditis is
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Viridans streptococci
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Which characteristic is TRUE for Neisseria?
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Anaerobic
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A gram-negative, nonmotile rod producing a large mucoid colony on agar medium was isolated from a chronically ill patient who died of pneumonia. The organism most likely belongs to the genus
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Klebsiella
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Several family members complained of abdominal cramps and diarrhea shortly after a backpacking trip to the mountains in Alberta, Canada. The most probably etiologic agent is
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Giardia lamblia
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A young woman complained of vaginitis. She admitted to many sexual partners. motile flagellates were seen microscopically in a wet mount of vaginal discharge. The most probably organism is from which genus?
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Trichomonas
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Which of the following organisms is invasive and therefore the most dangerous?
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Entamoeba histolytica
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