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Block 3 Found Sci > 3-Bacteriology Intro > Flashcards

3-Bacteriology Intro Flashcards

1
Q

viruses

general

A

smallest infectious particles
require host cell for replication

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2
Q

bacteria

general

A

prokaryotic unicellular org
-no nuclei or mem bound organelles
-1 circular chromosome + small ribosomes
-cell wall of peptidoglycan
-respiration @ cytoplasmic mem

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3
Q

fungi

general

A

more complex eukaryotes
-uni or multi cellular
20 um

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4
Q

parasites

general

A

most complex microbe
eukaryote
uni or multi cellular

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5
Q

how to classify bacteria

A
  1. fundamental features- visible, nutrition, end products, surface molecules
  2. 16S rRNA gene seq bc highly conserved
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6
Q

bacteria shapes

A
  1. coccus (singular sphere), diplococci (2), cocci clusters, cocci chain
  2. coccobacillus (oval)
  3. bacillus (rod), rod chain, curved
  4. spirochete (squiggle)
  5. spirullum (spiral)
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7
Q

bacteria structure

A
  1. cytoplasm- chromo + ribos + mRNA + proteins
  2. cytoplasmic membrane-lipid bilayer, ETC
  3. cell wall- peptidoglycan
  4. appendages- pili, flagella
  5. capusle- polysac or amino acids, protect from immune system
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8
Q

cell envelope purpose

A

permeability
-keep things in/out
-passage for water, nutrients
-either gram pos or neg
-cell membrane + everything beyond

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9
Q

gram positive bacteria

cell envelope

A

thick external peptidoglycan layer only plasma membrane
-has teichoic acid + lipoteichoic acid transmembrane to promote attach to other bacteria/host cells (PAMPS)
-lipoteichoic links PG layer to cell membrane

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10
Q

gram negative bacteria

A
  1. plasma/inner membrane
  2. periplasmic space
  3. thin peptidoglycan layer
  4. outer membrane- inner leaflet of phospholipids + outer leaflet of LPS + porins
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11
Q

gram stain steps

A
  1. crystal violet- permeates exposed peptidoglycan
  2. gram iodine- binds CV = complexes
  3. decolorizer- alc or acetone, dehydrates PG layer, traps complex in pos or washes complex away in neg
  4. safranin red- stains both grams but CV darker so pos = purple, neg = red
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12
Q

peptidoglycan layer

function

A

exclusive to bacteria = drug target

for 1. cell shape
2. structural support- flagella attach, prevent osmotic lysis

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13
Q

peptidoglycan composition

A

-alternating beta-1,4 sugars (NAG and NAM)
-parallel strands crosslinked by peptide sidechains on NAM but vary by species

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14
Q

immune effects peptidoglycan

A
  1. activate complement = his release > hypotension/edema, neutrophil chemotaxis
  2. macrophage activation (TLR4/CD14) = IL1/IL6 > fever, TNF-a > fever hypotension, NO > hypotension, tissue factor activation>coagulation (DIC)
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15
Q

LPS structure

lipolpolysaccharide

A

endotoxin with 3 subunits
1. lipid A- endotoxin activity so massive immune resp, anchored to outer mem by FAs
2. core polysaccharide- branched polysac 9-12 sugars
3. O antigen- long linear polysac of repeating saccharide units, species variation

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16
Q

LPS function

A
  1. protect from complement bc tight packed and neg charge for permeability, prevents MAC from getting past O antigen
  2. activates immune system binding CD14 and TLR4 on APCs > fever, inflamm, septic shock
17
Q

mycoplasma

A

1 membrane
NO peptidoglycan or LPS

18
Q

chlamydia

A

2 membranes
sometimes peptidoglycan

19
Q

ehrilichia and anaplasma

cell envelope

A

2 membranes
NO peptidoglycan or LPS

20
Q

mycobacteria and nocardia

cell membrane

A

1 membrane + peptidoglycan + thick waxy layer

21
Q

acid fast staining steps

A
  1. staining red by carbol fuchsin
  2. decolorization
  3. counterstain with methylene blue

whatever is left red is the acid fast bacteria aka stain not removed by acid alcohol wash

22
Q

acid fast examples

A
  1. mycobacteria
  2. actinomycetes
23
Q

acid fast cell wall

A

lipid AND mycolic acid rich outer layers
-resist gram staining so require specific technique

-LAM to hold waxy layer to membrane

24
Q

pili/fimbriae

A

proteinaceous hair like surface structures on various bacteria

does conjugation, motility, attachment

25
Q

flagella

A

rotating helical structures anchored to plasma mem for motility
-can be on one pole, both poles, or everywhere

26
Q

endospores

function

A

produced by gram pos bacteria to convert normal growing cell to a dormant state
- very resilient to pH, temp extremes, raditation, enzymes/chemicals

can germinate > single vegetative (growing) bacterium, og cell dies

27
Q

endospore structure

A

dehydrated, multilayer structure
-has complete copy of chromosome + minimum proteins and ribos

28
Q

endospore implications

A
  1. bioterrorism
  2. wide variety of environments
  3. exist for centuries
  4. need to be considered in sterilization, disinfection

Block 3 Found Sci (60 decks)

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