Chapter 25

1) Pathogenicity is the ability A) of the host to inflict damage on the pathogen. B) of the host to resist damage by the pathogen. C) of the pathogen to inflict damage on the host. D) None of these are correct.

C) of the pathogen to inflict damage on the host.

29) Siderophores are A) molecules that aid directly in attachment to host cells. B) inorganic molecules that help in active transport. C) organic molecules that help pathogens take up iron. D) toxins that affect the gastrointestinal tract.

C) organic molecules that help pathogens take up iron.

46) The process by which white blood cells ingest and kill bacteria is called A) exocytosis. B) transcription. C) phagocytosis. D) translation.

C) phagocytosis.

18) Capsules are particularly important for A) making bacteria more vulnerable to host defense mechanisms. B) making bacteria less pathogenic. C) protecting bacteria from host defense mechanisms. D) allowing bacteria to become more phagocytic.

C) protecting bacteria from host defense mechanisms.

24) The spread of pathogens through the blood and lymph systems that results in a bloodborne systemic infection is called A) bacteremia. B) cancer. C) pathogenesis. D) septicemia.

D) septicemia.

26) Which of the following is more likely to cause urinary tract infections? A) fimbriated strains of Escherichia coli B) non-fimbriated strains of Escherichia coli C) both fimbriated and non-fimbriated strains of Escherichia coli D) None of the answers are correct.

A) fimbriated strains of Escherichia coli

36) ________ is a damage or injury to a host organism that impairs its function. A) Trauma B) Infection C) Disease D) Transmission

C) Disease

42) The dose of an antigen that kills 50% of animals in a test group and is used to estimate the virulence of a pathogen is known as A) Antigen dose50. B) Virulence-50. C) LD50 (lethal dose50). D) Death rate-50.

C) LD50 (lethal dose50).

13) The α-toxin of Clostridium perfringens is A) an endotoxin. B) an enterotoxin. C) a lecithinase. D) a superantigen toxin.

C) a lecithinase.

28) Which of the following does NOT affect pathogen growth? A) availability of microbial nutrients B) pH C) temperature D) All of these answer choices affect growth.

D) All of these answer choices affect growth.

48) ________ are toxic proteins released from the pathogen during normal growth. A) Endotoxins B) Exotoxins C) Macrotoxins D) Microtoxins

B) Exotoxins

33) ________ in saliva cleaves glycosidic linkages in the peptidoglycan that is present in bacterial cell walls, weakening the wall and potentially causing cell lysis. A) Mucus B) Lysozyme C) Fibrin D) Lipid A

B) Lysozyme

25) Which genus produces hyaluronidase? A) Mycobacterium B) Streptococcus C) Shigella D) Procholorococcus

B) Streptococcus

50) ________ are microbial infections acquired by hospital patients with noninfectious diseases because they are compromised hosts. A) Healthcare-associated infections B) Immunocompromised infections C) Pathogenic infections D) Virulent infections

A) Healthcare-associated infections

8) Shiga toxin is an enterotoxin that is produced by A) Shigella dysenteriae. B) Clostridium tetani. C) Escherichia coli O157:H7. D) Vibrio cholerae.

A) Shigella dysenteriae.

40) Which of the following pathogens does NOT use capsules or a slime layer for attachment? A) Vibrio cholera B) Streptococcus pneumonia C) Bacillus anthracis D) All of these pathogens use capsules or slime layers for attachment.

A) Vibrio cholera

17) An outer coat consisting of a dense, well-defined polymer layer surrounding a cell and used in attachment is called a A) capsule. B) cytoplasmic membrane. C) lipopolysaccharide layer. D) pilus.

A) capsule.

49) Which of the following is a category of exotoxin? A) cytolytic toxin B) lipophilic toxin C) α-toxin D) β-toxin

A) cytolytic toxin

41) Which of the following is a major growth-limiting micronutrient that influences microbial growth? A) iron B) water C) vitamin K D) sugar

A) iron

14) Which of the following hemolysins is a phospholipase? A) lecithinase B) streptolysin-O C) Staphylococcal α-toxin D) leukocidin

A) lecithinase

22) Which of the following is NOT important for the adherence of bacteria to host tissues? A) lipopolysaccharides B) capsule C) adhesins D) slime layer

A) lipopolysaccharides

21) Which disease CANNOT be prevented via the use of a vaccine generated from an attenuated pathogen? A) malaria B) measles C) mumps D) rubella

A) malaria

7) Tetanus toxin causes A) muscles to be unable to relax. B) muscles to be unable to contract. C) severe diarrhea. D) hemolytic uremic syndrome.

A) muscles to be unable to relax.

20) It is thought that attenuation occurs especially in a laboratory setting because A) nonvirulent or weakly virulent mutants grow faster in laboratory media when there is no selective advantage to virulence. B) pathogens lose virulence with age and survive longer in laboratory cultures. C) patients can be treated with drugs that induce attenuation. D) there is selection for more virulent strains in the laboratory.

A) nonvirulent or weakly virulent mutants grow faster in laboratory media when there is no selective advantage to virulence.

43) The best term to describe the general process by which microorganisms cause diseases is known as A) pathogenesis. B) virulence. C) invasion. D) infection.

A) pathogenesis.

31) Which of the following is a reason that specific pathogens tend to infect specific tissues? A) Some tissues have receptors for microbes, but others do not. B) There are chemical and physical differences between tissues. C) Tissues with neutral pH are colonized but those with acidic or alkaline pH are not. D) Microbes preferentially target external tissues, such as skin, as the environment is more favorable for their growth than inside the body.

B) There are chemical and physical differences between tissues.

4) Diptheria toxin is a A) type of endotoxin. B) cytolytic toxin. C) AB toxin. D) superantigen toxin.

C) AB toxin.

6) The following bacterial genera are all implicated in dental caries EXCEPT A) Fusobacterium. B) Borrelia. C) Streptococcus. D) Corynebacterium.

B) Borrelia.

38) Epithelial cells lining the respiratory tract form a A) dry and rigid barrier with tight junctions between cells. B) impenetrable barrier to infection. C) mucous membrane. D) connective tissue layer.

C) mucous membrane.

37) Pathogenicity and virulence differ in that A) pathogenicity refers to the overall ability of a microbe to cause disease, whereas virulence refers to the ability of one microbe to cause disease relative to another. B) virulence refers to the overall ability of a microbe to cause disease, whereas pathogenicity refers to the ability of one microbe to cause disease relative to another. C) pathogenicity only refers to pathogens, whereas virulence refers to any microbe that can cause an infection. D) virulence only refers to pathogens, whereas pathogenicity refers to any microbe that can cause an infection.

A) pathogenicity refers to the overall ability of a microbe to cause disease, whereas virulence refers to the ability of one microbe to cause disease relative to another.

16) Influenza virus targets A) respiratory epithelium. B) gastrointestinal cells. C) oral cavity cells. D) throat epithelium.

A) respiratory epithelium.

45) Septicemia is an example of a A) systemic infection. B) transient infection. C) localized infection. D) autoimmune infection.

A) systemic infection.

32) The collective term for the organisms living on or in the human body, as opposed to a general term for organisms in an environmental habitat, is A) the human microbiome. B) the microbiota. C) transient microbial flora. D) pathogens.

A) the human microbiome.

15) Salmonella species use ________ to facilitate attachment to gastrointestinal tissue. A) type I fimbriae B) antiphagocytic proteins C) siderophores D) pili

A) type I fimbriae

10) An endogenous pyrogen is A) a chemical from the bacterial cell wall that causes fever. B) a chemical produced by a host's own immune system that causes fever. C) a chemical released by a bacterial cell that causes fever. D) a chemical produced within a bacterial cell that is released during cell division or at death of the bacterium, at which point it causes fever.

B) a chemical produced by a host's own immune system that causes fever.

19) The decrease or loss of virulence of a pathogen is referred to as A) aging. B) attenuation. C) disinfectivity. D) lethal dose.

B) attenuation.

47) The condition that results when some bacteria are shed in the bloodstream and distributed to distant parts of the body but do not reproduce in the blood is called A) septicemia. B) bacteremia. C) uremia. D) erythemia.

B) bacteremia.

11) Staphylococcus aureus produces ________, leading to fibrin clots that protect them from attack by host cells. A) collagenase B) coagulase C) lipase D) amylase

B) coagulase

27) Which of the following is NOT an example of an AB toxin? A) shiga-like toxin B) hemolysins C) botulinum toxin D) tetanus toxin

B) hemolysins

23) Which of the following is an important factor in the development of dental caries? A) high salt diet B) high sugar diet C) high acid diet D) low salt diet

B) high sugar diet

34) Which of the following is a way to prevent attenuation and maintain virulence in a bacterium? A) laboratory subculture B) inoculating an animal with the bacterium C) polymerase chain reaction (PCR) D) antibiotic therapy

B) inoculating an animal with the bacterium

3) Staphylococcus aureus and Streptococcus pyogenes strains can produce ________ that cause the severe and sometimes life-threatening symptoms of toxic shock syndrome. A) endotoxin B) superantigen toxins C) AB toxins

B) superantigen toxins

39) What is the difference between adherence and colonization? A) Colonization occurs when transient microbes are on a tissue, whereas adherence is a more permanent attachment to cells. B) Colonization occurs when microbes begin to spread in host tissues, whereas adherence occurs when microbes initially attach. C) Colonization occurs when microbes begin to spread in host tissues, whereas adherence occurs when microbes first begin to reproduce in the host tissues. D) Colonization occurs when a microbe begins to grow in host tissues whereas adherence occurs when the microbe initially attaches.

D) Colonization occurs when a microbe begins to grow in host tissues whereas adherence occurs when the microbe initially attaches.

2) Which of the following is NOT a subunit of lipopolysaccharide (LPS)? A) O-specific polysaccharide B) lipid A C) core polysaccharide D) M protein

D) M protein

12) Compared with an endotoxin, would a bacterial exotoxin generally be more likely to function after it had been significantly heated? A) Yes, because exotoxins are very heat stable compared to endotoxins. B) Yes, because exotoxins are proteins and non-living but endotoxins are part of the bacterial cell wall. C) No, because exotoxins are carbohydrates and endotoxins are proteins. D) No, because exotoxins are heat-labile and less resistant to heating than endotoxins.

D) No, because exotoxins are heat-labile and less resistant to heating than endotoxins.

35) Which of the following is TRUE about flagella? A) They are the most important structure in adherence. B) They are not involved in adherence and colonization at all. C) They are as important in adherence as pili and fimbriae. D) They may be involved in adherence to a lesser extent than pili and fimbriae.

D) They may be involved in adherence to a lesser extent than pili and fimbriae.

30) Cytolytic toxins A) are extracellular proteins. B) cause cell lysis and death. C) damage host cytoplasmic membrane. D) are extracellular proteins that cause cell lysis and death by damaging the host cytoplasmic membrane.

D) are extracellular proteins that cause cell lysis and death by damaging the host cytoplasmic membrane.

44) The macromolecules responsible for bacterial adherence that are NOT covalently attached to bacteria are collectively called A) lipid A. B) biofilms. C) capsules. D) glycocalyx.

D) glycocalyx.

5) Decalcification of the tooth enamel is caused by A) lipopolysaccharide. B) dextrans. C) formic acid. D) lactic acid.

D) lactic acid.

9) Exotoxins are ________, but endotoxins are ________. A) lipopolysaccharide-lipoprotein complexes / proteins B) carbohydrates / proteins C) lipids / proteins D) proteins / lipopolysaccharide-lipoprotein complexes

D) proteins / lipopolysaccharide-lipoprotein complexes