Deck 23: Microbial Interactions With Humans

Question 1

Following antibiotic therapy,patients are often administered ________ to facilitate recolonizaton of normal flora.

A)fluoride
B)iron
C)probiotics
D)antivirals

Answer 1

C

Question 2

Which of these microorganisms is MOST likely to be found in the human gut?

A)Helicobacter pylori
B)Streptococcus sobrinus
C)Streptococcus mutans
D)Roseobacter denitrificans

Answer 2

A

Question 3

The following bacterial species are all implicated in dental caries EXCEPT

A)Fusobacterium.
B)Borrelia.
C)Streptococcus.
D)Lactobacillus.

Answer 3

D

Question 4

One microenvironment of the skin is an area where glands produce an oily substance called

A)mucus.
B)sebum.
C)fimbrae.
D)lipid A.

Question 5

Influenza virus targets

A)respiratory epithelium.
B)gastrointestinal cells.
C)oral cavity cells.
D)throat epithelium.

Question 6

Staphylococcus aureus produces ________,leading to fibrin clots that protect them from attack by host cells.

A)collagenase
B)coagulase
C)lipase
D)amylase

Question 7

Decalcification of the tooth enamel due to the production of high concentrations of organic acids in the mouth is known as

A)degenerative plaque.
B)dental caries.
C)dental plaque.
D)microbial enamel decalcification.

Question 8

Normal flora in the duodenum are

A)similar to the microflora in the stomach.
B)dominated by aerobic organisms.
C)tolerant to alkaline environments.
D)tolerant to high salinity.

Question 9

The vagina of adult female is

A)highly acidic.
B)highly alkaline.
C)weakly acidic.
D)weakly alkaline.

Question 10

Attenuation occurs in a laboratory,because

A)nonvirulent or weakly virulent mutants grow faster in vitro in laboratory media.
B)pathogens lose virulence with age.
C)patients are generally treated with drugs that induce attenuation.
D)None of the answers are correct.

Question 11

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.

Question 12

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.

Question 13

Streptocoocus pyogens utilizes M protein and ________ to form microfibrils that facilitate attachment to host cells.

A)lipoteichoic acid
B)mucus
C)plaque
D)None of the answers are correct.

Question 14

Only particles smaller than ________ µm in diameter reach the lungs.

A)10
B)20
C)30
D)40

Question 15

Which of the following are NOT found in the gastrointestinal tract of healthy humans?

A)Bacteroides
B)Clostridium
C)Escherichia coli
D)protists

Question 16

A polymer coat consisting of a dense,well-defined polymer layer surrounding a cell is called a

A)capsule.
B)glycocalyx.
C)lipopolysaccharide.
D)slime mold.

Question 17

The following compounds are all produced by intestinal microflora EXCEPT

A)flatus.
B)vitamin C.
C)vitamin B₁₂.
D)vitamin K.

Question 18

Which of the following hemolysins is a phospholipase?

A)lecithinase
B)Streptolysin-O
C)Staphylococcal -toxin
D)leukocidin

Question 19

The decrease or loss of virulence of a pathogen is referred to as

A)aging.
B)attenuation.
C)disinfectivity.
D)lethal dose.

Question 20

Which of the following is NOT a subunit of lipopolysaccharide (LPS)?

A)O-specific polysaccharide
B)lipid A
C)core polysaccharide
D)M protein

Question 21

Which of the following environmental and host factors influence the composition of resident microflora on the skin?

A)age
B)personal hygiene
C)weather
D)age,personal hygiene,and weather

Question 22

Pathogenic strains of Escherichia coli usually express

A)capsules.
B)colonization factor antigens (CFA).
C)plaques.
D)slime layers.

Question 23

Which genus produces hyaluronidase?

A)Mycobacteria
B)Streptococcus
C)Shigella
D)Procholorococcus

Question 24

Virulence is the relative ability of a ________ to cause disease.

A)pathogen
B)commensal
C)virus
D)bacterium

Question 25

Which of the following is NOT important for the adherence of bacteria to other bacteria as well as to host tissue?

A)adherence polymers
B)capsule
C)glycocalyx
D)slime layer

Question 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.

Question 27

Which of the following is the dominate genera of skin microflora?

A)Bacteriodes
B)Firmicutes
C)Actinobacteria
D)Proteobacteria

Question 28

Which of the following does NOT affect pathogen growth?

A)availability of microbial nutrients
B)pH
C)temperature
D)doubling time

Question 29

A(n)________ is a damage or injury to a host organism that impairs its function.

A)trauma
B)infection
C)disease
D)transmission

Question 30

Extensive growth of the streptococci in a thick bacterial layer on acidic glycoproteins on the teeth is called

A)dental plaque.
B)dental caries.
C)dental biofilm.
D)periodontitis.

Question 31

________ in saliva cleaves glycosidic linkages in peptidoglycan present in bacterial cell walls,weakening the wall and causing cell lysis.

A)Mucus
B)Lysozyme
C)Fibrin
D)Lipid A

Question 32

Which disease CANNOT be prevented via the use of a vaccine generated from an attenuated pathogen?

A)malaria
B)measles
C)mumps
D)rubella

Question 33

The collective term for the organisms living on or in the human body is

A)normal microbial flora.
B)fomite flora.
C)transient microbial flora.
D)pathogenic flora.

Question 34

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.

Question 35

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

Question 36

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.

Question 37

Normal flora ________ colonization of pathogenic organisms.

A)promote
B)prevent
C)maintain
D)accelerate

Question 38

Siderophores from some pathogens remove iron from the host protein(s)

A)lactoferrin.
B)transferrin.
C)both lactoferrin and transferrin.
D)cytochromes.

Question 39

Which of the following is a way to prevent attenuation and maintain virulence in a bacterium?

A)laboratory subculture
B)animal passage
C)polymerase chain reaction (PCR)
D)antibiotic therapy

Question 40

The human gastrointestinal tract includes all of the following EXCEPT the

A)small intestine.
B)stomach.
C)large intestine.
D)epiglottis.

Question 41

Which of the following is a category of exotoxin?

A)cytolytic toxin
B)lipophilic toxin
C)α-toxin
D)β-toxin

Question 42

Normal microflora are usually found in the blood,lymph,and nervous systems of the body.

Question 43

Which of the following pathogens does NOT require capsules or a slime layer for attachment?

A)Vibrio cholera
B)Streptococcus pneumonia
C)Bacillus anthracis
D)All of these pathogens require capsules or slime layers for attachment.

Question 44

Virulence refers to the ability of an organism to cause disease.

Question 45

Pathogen virulence NEVER changes throughout a host's life.

Question 46

________ are toxic proteins released from the pathogen as it grows.

A)Endotoxins
B)Exotoxins
C)Macrotoxins
D)Microtoxins

Question 47

Which of the following is a major growth-limiting micronutrient that influences microbial growth?

A)iron
B)transferrin
C)lactoferrin
D)sugar

Question 48

The condition that results when some organisms are shed in the bloodstream and distributed to distant parts of the body during bacterial growth in tissues is called

A)septicemia.
B)bacteremia.
C)uremia.
D)erythemia.

Question 49

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.

Question 50

Protists are NOT normally found in the gastrointestinal tract of healthy individuals.

Question 51

A loose network of polymers extending outward from a cell is called a(n)

A)slime layer.
B)lipid A.
C)capsule.
D)adhesion.

Question 52

Bacteria found in the mouth in the first years of life are well-adapted to biofilm formation.

Question 53

An opportunistic pathogen causes disease ONLY in the presence of normal host resistance.

Question 54

________ 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

Question 55

Streptococcus mutans can produce dextran when sucrose is present in the absence of the enzyme dextransucrase.

Question 56

The process by which microorganisms cause diseases is known as

A)pathogenesis.
B)virulence.
C)LD₅₀ (lethal dose₅₀).
D)infection.

Question 57

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.

Question 58

The process by which white blood cells ingest and kill bacteria is called

A)exocytosis.
B)transcription.
C)phagocytosis.
D)translation.

Question 59

Cholera begins following a bite from a mosquito.

Question 60

ALL microorganisms that live in the human body are harmful.

Question 61

Why are some microorganisms specialized to only certain parts of the body? Describe an example that supports your answer.

Question 62

Vaginal acidity in the adult female is due to acid production by Lactobacillus acidophilus.

Question 63

Design an experiment to determine whether a potential pathogen produces hemolysins.

Question 64

Endotoxins are released in large amounts only when cells lyse.

Question 65

Bacteria make up about one-third the weight of fecal matter.

Question 66

Invasion is the ability of a pathogen to enter into host cells or tissues,spread,and cause disease.

Question 67

The toxic lipopolysaccharides produced by MOST gram-negative bacteria are called exotoxins.

Question 68

Hormones that are produced under stress boost normal immune responses and play a role in stress-mediated disease resistance.

Question 69

When does an infection become a disease?

Question 70

The upper respiratory tract usually has a considerable amount of resident microflora in a healthy adult.

Question 71

Diphtheria toxin inactivates elongation factor 2 by catalyzing the attachment of adenosine diphosphate ribose from NAD⁺.

Question 72

Gram-positive bacteria produce endotoxins.

Question 73

Explain how diet plays a role in host susceptibility to infection.

Question 74

R plasmids help prevent the spread of virulence factors.

Question 75

Clostridium botulinum are endospore-forming bacteria normally found in the soil.

Question 76

Malassezia spp.are the MOST common fungi present on the skin of humans.

Question 77

Animals that lack CXCR4 and CCR5 proteins are immune to HIV infection.

Question 78

The Limulus amebocyte lysate assay is used to detect endotoxin in clinical samples such as serum or cerebrospinal fluid.

Question 79

The number of Vibrio cholera cells necessary to produce cholera in an exposed individual is drastically reduced if the individual is malnourished.

Question 80

Clostridium botulinum cannot produce toxins in improperly preserved foods.