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microbiology > L1. Classification by structure, replication, metabolism > Flashcards

L1. Classification by structure, replication, metabolism Flashcards

1
Q

What are bacterial fimbriae used for?

A

adhesion

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2
Q

what are mesosomes used for?

A

areas in the cell membrane of bacteria that fold inward - play an important role in cellular respiration

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3
Q

Which bacterial species does not have a cell wall as the outermost layer?

A

mycoplasma (b/w capsule and cytoplasmic membrane)

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4
Q

what are other names for peptidoglycan? (2)

A

murein or mucopeptide

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5
Q

what are the components of the bacterial peptidoglycan layer? (5)

A

diaminopimelic acid

muramic acid (ex NAM)

techoic acid

pentaglycine crossbridge

tetrapeptide sidechain

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6
Q

what is the function of diaminopimelic acid?

A

forms peptide linkages in bacterial peptidoglycan

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7
Q

what is the function of muramic acid?

A

structural component of peptidoglycan (NAM and NAG)

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8
Q

what is the function of techoic acid?

A

to provide rigidity to the cell-wall by attracting cations such as magnesium and sodium

go through PG (perpendicular to it)

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9
Q

what is the function of the pentaglycine crossbridge?

A

structural component that “cross” with muramic acid (NAM and NAG)

this is the component inhibited by beta lactam antibiotics!

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10
Q

what is the function of tetrapeptide sidechain?

A 
contains: 
L alanine
D glutamic acid
L lysine
D alanine
helps add layers within PG (how i see it)
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11
Q

where does lysozyme act on peptidoglycan?

A

beta 1 - 4 linkages b/w NAG and NAM

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12
Q

what are the stain colours for gram pos/neg

A

pos - purple

neg - pink

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13
Q

does the cytoplasmic membrane of bacteria contain cholesterol? :)

A

no :( relax

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14
Q

what are the major differences b/w gram pos and gram neg cell wall?

A

gram negative has unique outer cell membrane

peptidoglycan is thin and within “periplasmic space”

instead of techoic acid, has murein lipoprotein (extends from PG to outer cell membrane)

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15
Q

whats unique about the outermost cell layer of gram neg cell wall?

A

its existence

outermost portion contains LPS!

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16
Q

Whats the structure of LPS?

A

O polysacc: outer carbohydrate chain (vary 1 - 50)

core polysacc: centre part

Lipid A: phosphorylated glucosamine disacc

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17
Q

whats the most toxic part of LPS?

A

Lipid A aka the gram negative endotoxin

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18
Q

what is the function of LPS?

A

blocks passage of substances to peptidoglycan layer

in humans can cause septic shock

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19
Q

what does pleomorphic mean?

A

bacteria lacking a distinct shape

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20
Q

how do bacteria cells reproduce?

A

binary fission (literally divide into two)

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21
Q

what are endospores?

A

dormant, tough, non reproductive structure produced by a small number of bacteria

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22
Q

what is sporulation?

A

process of forming an endospore

occurs when environment is unfavourable

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23
Q

what are the two most important bacteria that form endospores? why?

A

bacillus and clostridium

why? because important PATHOGENS

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24
Q

what are the stages of endospore germination?

A
  1. activation: can only be activated a few days after being formed
  2. initiation: autolysin degrades cortex peptidoglycan; calcium dipicolinate is released
  3. outgrowth: emergence of new vegetative cell consisting of spore protoplast w/ surrounding wall
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25
what is calcium dipicolinate (2)?
protects DNA of spore from heat denaturation (inserts itself in b/w DNA bases) dehydrates the spore
26
What are the seven spore forming bacteria?
Bacillus anthracis and cereus Clostridium botulinum, perfringens, difficile and tetani
27
what does bacillus cereus cause?
food poisoning
28
How do you stain for an endospore to be visible (2)?
Schaeffer - Fulton method: - malachite green (primary stain - endospores) - safranin (counter stain - vegetative)
29
what is the only bacteria with a capsule made of protein?
bacillus anthracis
30
How do you stain for a capsule?
negative staining: stains the background
31
what is the quelling reaction?
antibody reaction w/ capsule - capsule swells
32
What are the nine encapsulated bacteria?
Yes Even Some Pretty Nasty Killers Have Shiny Bodies ``` yersinia pestis E coli strep pneumonia pseudomonas aeruginosa Neisseria meningitides Klebseilla pneumonia H. influenza Salmonella typhi Bacillus anthracic ```
33
What are the different types of flagella (4)?
Monotrichous: single polar flagellum lophotrichous: 2 or more flagella at one end amphitrichous: 1 or more flagella on both ends peritrichous: flagella all over
34
How is flagella stained (2)?
first apply a mordant (tannic acid or potassium alum) then stained w/ pararosaniline or basic fuschin
35
Which class of bacteria are mesosomes more prominent in?
gram positive bacteria
36
fimbriae vs pilli
pilli are usually longer and are also involved in transfer of dna during conjugation
37
endotoxins vs exotoxins
endotoxins - usually by gram negative bacteria; structural components exotoxins: usually by gram positive bacteria, proteins
38
What are the 7 classic gram positive bugs that cause disease in humans?
cocci: strep entero staph ``` bacilli: bacillus clostridum corynebacterium listeria ```
39
what are the 2 groups of gram negative cocci?
diplococci: | neisseria and moraxella
40
What is an oxidase test used for?
blue - positive yellow - negative detects the presence of cytochrome oxidase -> used in ETC!
41
which gram positive bacteria is identified with acid fast stain?
mycobacteria
42
what is the first line lab test used to identify bacteria?
gram stain
43
what are the 11 bacteria that are not stained well by gram stain?
These Little Microbes May Unfortunately Lack Real Colour But Are Everywhere Treponema, Leptospira (too thin to be seen) Mycobacteria (high lipid content in cell wall) Ureaplasma, Mycoplasma (no cell wall) Legionella, Rickettsia, Chlamydia, Bartonella, Anaplasma, Ehrlichia
44
why is chlamydia known to be lacking "classic peptidoglycan"?
when it is intracellular, muramic acid is reduced
45
what are some of the other stains available?
india ink fluorescent antibody silver stain albert stain
46
what is silver stain used for?
Fun legions are hyped Fungi, Legionella, and H. pylori
47
what is albert stain used for?
granules - red to violet rest of bacteria - blue/green stains "volutin" granules in C diphtheria
48
What is india ink used to identify?
cryptococcus neoformans
49
What is a common acid fast stain?
zeihl neelsen stain carbol fuschin - primary stain methylene blue - secondary stain (for non acid fast bacteria)
50
what are the four acid fast bacteria?
mycobacterium tuberculosis mycobacterium leprae nocardia asteroids actinomycetes
51
what are voluntin granules?
food stores found in bacteria
52
what is albert stain made of (2) ?
toluidine blue and malachite green
53
what is thayer martin agar used for?
selective growth of Neisseria (gonnorhoeae and meningitides)
54
what is colistin used for?
inhibits most gram neg bacteria other than Neisseria
55
What is vancomycin used for?
selective media tha inhibits most gram pos bacteria
56
what is nystatin used for?
inhibits yeast
57
what is modiefied thayer martin agar used for?
contains added trimethoprim to inhibit proteus!
58
What is McConkey agar used for?
to differentiate between lactose and non lactose fermenters lactose fermenter - turns pink
59
what is CHROMagar used for?
to identify enterococcus faecalis (turns green)
60
what is E coli grown on?
blood agar
61
what is serratia grown on?
chocolate agar
62
What is chocolate agar used for (5)?
to grow h. influenza, serratia, neisseria species (g and m) and haemophillus
63
What is regan lowe medium used for?
to grow pertussis contains charcoal, blood and antibiotic + potato extract
64
What is eaton agar used for?
Mycoplasma pneumoniae | gram neg
65
What is EMB (eosin methylene blue) agar used for?
E coli! produces "metallic sheen" colour
66
What is bordet gengou agar used for?
pertusis
67
what is sabouraud agar used for (2)? what does it contain?
fungi filamentous bacteria like nocardia! contains peptones!
68
what is tellurite agar used for?
Diptheria
69
what is mannitol salt agar used for (2)?
used to isolate Staph Aureus (yellow) serratia would be red
70
what is charcoal yeast extract buffered w/ cysteine and iron used for (4)?
Bruce Francis and the Legion of Pastors Brucella, francisella, legionella, pasteurella
71
what are the 4 aerobic bacteria?
Nagging Pests Must Breathe | Nocardia, pseudomonas, mycobacterium TB, bordetella pertussis
72
what are the 4 obligate anaerobes?
clostridium, bacteriodes, fusobacterium and actinomyces israelii
73
why can obligate anaerobes not survive in the presence of O2 (3)?
lack catalase susceptible to oxidative damage foul smelling and produce gas (CO2 and H2)
74
What are the 4 facultative anaerobes?
strep, staph and enteric gram positive bacteria as well as E coli
75
what are the urease positive organisms (5 + 3)?
PUNCH proteus, ureaplasma urealyticum, Nocardi, cryptococcus, H. pylori KISS klebsiella, S saprophyticus and S epidermidis
76
how does a urea breath test work?
patients ingest labelled urea if urease positive organisms are present, labelled CO2 will be detected (scintillation counter or special spectrometer)
77
what are the 3 obligate intracellular bacteria?
Really Chilly and Cold | Rickettsia, Chlamydia and Coxiella
78
what are the 4 biofilm producing bacteria?
Epic Virus Pink Homo | S. epidermidis, Viridans, Pseudomonas aeruginosa and H. influenza
79
where does S. epidermidis form biofilms (2)?
catheter and prosthetic devices
80
Where do viridans form biofilms?
dental plaques
81
Where does Pseudomonas form biofilms (2)?
respiratory infections and keratitis (contact lens associated)
82
Where does H. influenza form biofilms?
Otitis media (ear)
83
what is the temperature most pathogenic bacteria grow at?
37 deg
84
what bacteria grows well at 42 deg?
campylobacter
85
what bacteria grows at low temperatures (0 - 4 deg)?
listeria monocytogenes | food poisoning
86
what pathogenic protein is NOT destroyed by autoclave?
prion proteins
87
what can ethylene oxide not work against?
spores
88
what is hydrogen peroxide effective against?
all microorganisms including spores!
89
what is pasteurization NOT effective against?
heat resistant spores
90
did not include infection control!
x

microbiology (8 decks)

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