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NBDE Part 1 > Microbiology > Flashcards

Microbiology Flashcards

1
Q

What is commensalism?

A

A type of symbiosis where one organism benefits, but the other is neither helped nor harmed

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2
Q

What is the difference between an abscess and a granuloma?

A

Abscess: acute inflammatory lesion of pus
Granuloma: chronic inflammatory lesion full of fibrosis, angiogenesis, and inflammatory cells

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3
Q

Which microorginisms most commonly cause sepsis?

A

Bacteria only!

Staph. aureus, Klebsiella sp., and E. coli

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4
Q

Cysts are filled with _______.

A

fluid or air

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5
Q

All bacteria except _________ contain a plasma membrane surrounded by a __________ cell wall.

A

Mycoplasma; peptidoglycan

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6
Q

What surrounds the cell wall in bacteria?

A

polysaccharide capsule

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7
Q

Which bacteria has a protein containing D-glutamate capsule instead of a polysaccharide capsule?

A

Bacillus anthracis

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8
Q

What are the three ways bacteria exchange genetic information?

A

Transformation: uptake from environment
Conjugation: sex with plasmid
Transduction: viral

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9
Q

What enzymes allow for evasion of host defenses?

A

Coagulase: promotes clot
IgA protease: Strep. pneumoniae, H. influenzae, Neisseria sp.
Leukocidins: destroy PMNs and macrophages

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10
Q

What virulence factor destroys plasma membranes and causes gangrene?

A

Lecithinase

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11
Q

What three virulence factors cause Beta-hemolysis?

A

Streptolysin O
Streptolysin S
Pneumolysin

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12
Q

__________ are found within the cell wall and are only associated with gram - bacteria and listeria.

A

Endotoxins

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13
Q

T/F: LPS is an example of an endotoxin.

A

True

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14
Q

Enterotoxins are an example of ________ that affect intestinal endothelial cells.

A

exotoxins

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15
Q

List the exotoxins which are classified as ADP-ribosylation and increase adenylate cyclase activity.

A

Cholera (V. cholerae)
Pertussis (B. pertussis)
Anthrax - edema factor (B. anthracis)
Heat-labile toxin (E. coli)

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16
Q

T/F: The Diphtheria toxin increases adenylate cyclase activity.

A

False

Inhibits protein synthesis

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17
Q

Which bacteria utilize superantigens?

A

Staph. aureus - TSST

Strep. pyogenes - erythrogenic toxin

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18
Q

Clostridium tetani and clostridium botulinum both utilize protease exotoxins which function as _________.

A

neurotoxins

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19
Q

What type of exotoxin is the anthrax lethal factor?

A

Protease - cleaves phosphokinase

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20
Q

What are the three modes of action for endotoxins?

A
  1. Activate macrophages
  2. Activates compliment
  3. Activates hageman factor
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21
Q

Bacilla are _____ shaped bacteria.

A

rod

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22
Q

Cocci are ______ shaped bacteria.

A

round

23
Q

Which bacteria have a flexible thin cell wall?

A

Spirochetes

24
Q

Which two bacteria are known to be obligate intracellular bacteria?

A

Rickettsia and Chlamydia

25
Q

T/F: Mycobacteria have no cell wall.

A

FALSE

Mycoplasma: no cell wall

Mycobacteria: acid-fast extracellular bacteria

26
Q

What are the cocci shaped gram - and gram + bacteria?

A

Gram - : Neisseria

Gram + : Strep, Staph

27
Q

What do Bacillus and Clostridium species have in common?

A

Spore forming, gram + bacilli

28
Q

What do Actinomyces, Listeria, and Corynebacterium have in common?

A

Non-spore forming, gram + bacilli

29
Q

_________ is an aerobic, gram - bacilli.

A

Pseudomonas

30
Q

What is an anaerobic gram - bacilli?

A

Bacteroides

31
Q

What do Escherichia, Salmonella, and Helicobacter species all have in common?

A

Facultative gram - bacilli

32
Q

What are the cell wall characteristics of a gram + bacteria?

A

Stains purple
Thick (+ size)
Lipoteichoic acid (LTA)
No endotoxin

33
Q

What do obligate anaerobic bacteria lack that does not allow them to grow in oxygenated environments?

A

Superoxide dismutase and/or catalase

34
Q

Streptococci grow in _______, while staphylococci grow in _______.

A

pairs/chain; grapelike clusters

35
Q

Which streptococci are part of the normal flora of the mouth?

A

Viridans group: S. mutans and S. sanguis

36
Q

Which strep can cause meningitis, otitis media, pneumonia, and sinusitis?

A

S. pneumoniae

37
Q

T/F: S. pyogenes expresses alpha hemolysis.

A

False

Beta

38
Q

T/F: Enterococci express gamma hemolysis.

A

True

39
Q

What are the major virulence factors of Staph. aureus?

A

Protein A, beta-lactamase, enterotoxin

Causes abscess, pneumonia, toxic shock syndrome, food poisoning, MRSA, endocarditis, osteomyelitis

40
Q

Which staph causes UTIs?

A

S. saprophyticus

41
Q

What do Bacillus anthracis, Bacillus cereus, and Clostridium species all have in common?

A

Gram + spore-forming bacteria

42
Q

T/F: Actinomyces israelii is a gram + spore forming bacteria.

A

False

Gram + non-spore-forming

Has sulfur granules and is part of normal oral flora

43
Q

What do E. coli, Salmonella sp., Shigella sp., Vibrio cholerae, and H. pylori all have in common?

A

Gram - enteric bacilli

44
Q

Which bacteria causes pink eye?

A

Haemophilus aegyptius

45
Q

T/F: Mycoplasma pneumoniae causes true pneumoniae.

A

False

Walking pneumonia

46
Q

What are the three stages of the disease caused by Borrelia burgdorferi?

A

Lyme disease

  1. Erythema migrains (bulls eye)
  2. Neuropathies (Bell’s palsy)
  3. Arthritis and CNS disease
47
Q

Which organism is found most commonly on the surface of the tongue?

A

Strep. salivarius

48
Q

What is the dominant bacterial species of supragingival plaque?

A

Gram + facultative cocci

Subgingival = gram - anaerobic bacilli and spirochetes

49
Q

What is the epitactic concept?

A

Seeding agents (protein-carb complexes or bacteria) induce mineralization of calculus

50
Q

Caraiogenic bacteria synthesize ________ and _______ from their metabolism of dietary ________.

A

glucans (dextrans) and fructans (levans); sucrose

51
Q

Critical pH for for enamel is ____.

A

5.5

52
Q

Gingivitis associated with sex steroid fluctuations is associated with elevated levels of which bacteria?

A

Prevotella intermedia

53
Q

Which bacteria is often seen to be elevated in aggressive periodontitis?

A

A. a. and P. gingivalis

54
Q

Elevated proportions of spirochetes in the mouth is associated with _____.

A

NUG/NUP

NBDE Part 1 (31 decks)

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