Bacterial Classification and Structure Flashcards

1
Q

which bugs have capsule as major virulence factor?

A

SOME KILLERS HAVE PRETTY NICE CAPSULES

  1. strep pneumoniae
  2. kliebsiella pneumoniae
  3. haemophilus influenzae
  4. pseudomonas aeruginosa
  5. neisseria meningitidis
  6. cryptococcus neoformans
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2
Q

where are pili found

A

gram negative only

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3
Q

what component is responsible for cell shape and structural rigidity

A

peptidoglycan

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4
Q

what makes up peptidoglycan

A

NAG and NAM that are crosslinked by tetrapeptide bridge

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5
Q

describe gram positive cell wall

A

thick peptidoglycan, highly crosslinked, has lipoteichoic acid and teichoic acids

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6
Q

what do lipoteichoic acids do

A

anchor cell wall to cell membrane and mediate attachment

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7
Q

what do teichoic acids do

A

taxonomic markers , antigenic determinant

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8
Q

gram negative cell structure

A

2 membranes inner and outer, with periplasmic space, has less peptidoglycan with less crosslinkage

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9
Q

describe outer membrane of gram negative cell

A

gram negative has LPS, there is no active transport or enzymatic activity, there are porins and receptor proteins

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10
Q

what is a main part of LPS?

A

Lipid A

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11
Q

what is Lipid A?

A

heat stable endotoxin with a core region and polysaccharide side chain (o antigen) – a pyrogen

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12
Q

what does Lipid A do?

A

activates macrophages and complement and B cells
induces IFN production
causes tissue necrosis
pyrogen

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13
Q

what does O antigen do

A

is a major serologic determinant and a virulence factor (if smooth making O antigen, if rough not making O antigen)

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14
Q

what is in the periplasmic space?

A
  1. binding proteins
  2. degradative enzymes
  3. detoxifying enzymes
  4. super thin peptidoglycan cell wall
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15
Q

what detoxifying enzymes are in the periplasmic space?

A

beta lactamases (inhibit penicillin and cephalosporins, carbapenems, monobactams)

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16
Q

describe the inner membrane of (both gram positive and negative)

A

similar in both, NO STEROLS, osmotically fragile

HAS ENZYMATIC ACTIVITY, acts like osmotic barrier

17
Q

what type of activity does the cytoplasmic/inner membrane have?

A
  1. electron transport
  2. ox phosphorylation
  3. synthesis of peptidoglycan
  4. active transport
  5. bounds ribosomes
  6. simple and facilitated diffusion
18
Q

where do endospores come from

A

gram positive

19
Q

what is the purpose of becoming a spore

A

to survive and be stable not reproduce

20
Q

what triggers spore formation?

A

exhaustion of carbon or nitrogen source

21
Q

what is a big clue that someone has spore infection?

A

accumulation of large amounts of calcium and dipicolinic acid

22
Q

structure of endospore

A
  1. core with genome, DNA and ribosomes
  2. spore wall with peptidoglycan
  3. cortex with new peptidoglycan
  4. coat
  5. exosporium loose covering
23
Q

is there RNA or free AA in endospore core>

24
Q

thickest layer in endospore

A

cortex - concentric layers give strength

25
what is the benefit of a spore coat?
disulfide bonds and keratin like protein makes it resistant to chemicals and radiation
26
what triggers activation of spore germination?
either spontaneous or heat, aging, low pH, or chemical treatments
27
what occurs when spore germinates?
produces Ca and dipicolinic acid, hydrolysis begins and brings in water, but loses heat resistance
28
what is crucial for spore germination?
water
29
which bacteria are spore formers
1. clostridium tetani 2. clostridium botulinum 3. bacillus anthracis 3. bacillus cereus