Micro Exam 1 Test Questions – Flashcards

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Transmembrane protein

Integral protein

Peripheral protein

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t: protein that spans the entire biological membrane; type of intergral protein

i: protein that is permanently attached to the biological membrane

p: temporarily adhere to the biological membrane; attach to integral

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Nicholson-Singer fluid mosaic membrane model
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membrane/proteins are capable of lateral motion

some proteins embedded in membrane

in prokaryotic or eukaryotic

still considered most viable model of membrane since 1972

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2 structures for membrane stabilization
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1. Sterol- planar molecule, eukaryotic, cholesterol

2. hopanoid- 5 rings structure, prokaryotic, diploptene hopanoid

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Membrane functions (6)
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1. Semipermeable barrier

2. Regulation (metabolite uptake, waste release)

3. Redox reactions (electron transport systems)

4. Coordination of binary fission and sporulation (septum formation)

5. Synthetic reactions

6. Chemotaxis/sensing apparati

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3 types of synthetic reactions
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- lipids

- peptidoglycan

- secretory proteins

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How do molecules pass through a biological membrane?
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Phagocytosis

Endocytosis

Exocytosis

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Passive diffusion vs. facilitated transport
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p: water/co2 can simply diffuse high to low through membrane

f: need transport or carrier protein when available

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Other terms for facilitated diffusion
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Transporters

Permeases

Facilitators

Carriers

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Sources of energy in a cell
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ATP- adenosine triphosphate

PMF- proton motive force (electrochemical gradient)

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2 types of transporters
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MFS- major facilitator superfamily

IDS- ion dependent transport system

** depend on concentration gradient**

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Cotransport systems (3)
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Utilize energy of PMF

1. Symport- same way down channel, prokaryotic sugars/ eukaryotes

2. Antiport- one in, one expelled

3. Uniport- one one material down channel

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Efflux system
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part of antiport

expulsion of antibiotic or waste

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ABC transport system
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ATP binding cassette

3 regions:

1. Solute binding protein (SBP)- attaches to appropriate protein and brings to mouth of channel (g+ can diffuse away, g- close because of periplasm)

2. Membrane spanning domain (MSD)- 2 barrel channel through protein, 12 alpha helices lining

3. Nucleotide binding domain (NBD)- binding of ATP

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Group translocation system
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Prokaryotes only

chemically alters substrate

12 alpha helices in transmembrane protein

phosphorylation energy from PEP

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Do prokaryotes or eukaryotes have more proteins?
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Prokaryotic - 800

Eukaryotic- 225

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Bactoprenol
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transports NAM and NAG across the cell membrane in the synthesis of peptidoglycan
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Secretory systems (4)
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Translocase (expulsion)

Sec system

Type III (injectisome)

Signal sequence

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Sec system
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- secA translocase- secretion and insertion of proteins in the cell membrane

- leader sequence of 15-20 amino acids

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Type III secretion system
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- AKA: injectisome

- in gram negative bacteria

- produce a toxin that inserts into eukaryotic cell

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Characteristic structures when the cell membrane invaginates
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- still continuous with cell membrane

- see by electron microscopy

- structures: tubes, vesicles, bundled tubes, stacks, lamellae

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Another name for glycocalyx
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EPS- extracellular polymeric substance
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Types of glycocalyces
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1. capsule- distinct gelatinous layer for protection/attachment

2. slime layer- diffuse and irregular layer for protection/attachment

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Visualization of glycocalyx
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external to cell wall

do not stain well

- negative/background stain (stain everything were not interested in)

- india ink

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3 bacteria causing pneumonia
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Klebsiella pneumoniae

Streptococcus pneumoniae

Mycoplasma pneumoniae

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Glycocalyx colonies (2)
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1. smooth- AKA mucoid, mucous/stringy

2. rough- little extracellular matrix material

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Chemical composition of glycocalyx
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primarily sugar polymers (polysaccharides)

few amino acids (polypeptides)

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What makes up polysaccharides?
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glucans and dextrans

(glucose)

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What genus gives a proteinacious glycocalyx?
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Bacillus spp.
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Glycocalyx functions (6)
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1. Adhesions/adherence

2. Protection against dessiccation

3. Protect against bacteriophage infecton and noxious chemicals

4. Carbohydrate reserve (?)

5. Protection against elimination by phagocytosis (virulence mechanism)

6. Classification and type specific markers for Streptococcus pneumoniae 

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Biofilm

(definition and 3 examples)

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polysaccharide encased mass of bacteria coating a surface

- can only cause disease if encapsulated

ex) Streptococcus mutans - dental plaque

Streptococcus pneumoniae - low bar pneumonia (elderly)

Haemophilis influenzae- infections in children (ear)

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Classification by type specific markers
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K or Vi antigens
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Dental caries
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dental plaque

Streptococcus mutans

most common infectious disease

due to excess sucrose

attaches to teeth, anaerobic environment, sugar ferments, acid prodcued, tooth erosion

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Types of pili/fimbriae
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1. Conjugal, fertility, sexual- has to do with genes (uncommon)

2. Somatic/body- designated by type and function

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CFA & PAK
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CFA: colonization factor antigen in E. coli

PAK: causes thrush

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Functions of pili
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1. gene transfer (conjugation)

2. Anti-phagocytic

3. Adherence

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Adherence mechanisms among prokaryotes (2)
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Afimbrial: due to glycoclayx, adhesins embedded

Fimbrial: due to fimbriae/pili, adhesins at end of pilus with O markers

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E. coli fimbrial systems (5)
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1. ETEC- enterotoxinogenic ecoli- binds to enterocytes in intestinal epithelium

2. EIEC- enteroinvasive ecoli

3. EAEC- enteroaggregative ecoli

4. EPEC- enteropathogenic ecoli

5. EHEC- enterohemorrhagic ecoli (O157)

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Fimbrial system bacteria (3)
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Klebsiella pneumoiae

Pseudomonas aeruginosa (cystic fibrosis)

Candida albicans (eukaryotes, fungus, PAK)

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Tropism

(definition and 2 examples)

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act on cell with appropriate receptor

Streptococcus pyogenes - receptors in back of the throat

Bordetella pertusis- whooping cough, receptors in respiratory tract

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Flagella shapes (5)
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1. Monotrichous: polar, single flagella on one side

2. Amphitrichous- 2 to 4 flagella on both sides

3. Lophotrichous- many flagella on one side

4. Peritrichous- flagella all around, evenly distributed

5. Atritrichous- no flagella, still motile

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Sinusoidal shape of flagella
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same wavelength and amplitude

rigid

helical

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Pilin
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protein subunits of pili that are unique in every pilus
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3 components of flagella
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Basal body/granule

Hook

Filament

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Basal body/granule

(definition & g+/g-)

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- tube with several sets of rings attached

in every bacterial cell w/ flagella

- anchors flagellum to cell wall/membrane

g-: 2 sets of rings, top & by stator, perimplasmic space

g+: one set of rings around stator

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Stator
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part of basal body/granule

where motion is generated from PMF

rapid rotation

embedded in cell membrane

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Hook
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-part of flagella that swings out due to centrifugal force

-amino acids/proteins

-connects filament to cell surface

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Circumferential slip
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push or pull bacteria from aqueous environment

- due to rotation from basal body

- drill bit

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Filament
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rigid

rotates

extends into exterior environment

majority of flagella (stringy)

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3 ways to identify flagella
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1. leifsons flagellar stain: salt along flagella visible with light microscopy

2. wet mounts- see organism as it moves through aqueous environment

3. motility detection medium

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Spirochetal Ultrastructure
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type of flagella in spirochetes

spirillum morphology

AKA: endoflagella & axial fibrils

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Inside spirochetal ultrastructure
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1. peptidoglycan: patches, flexible

2. axial filaments: folded inside cell

3. protoplasmic cylinder: cell membrane, peptidoglycan, outer sheath

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Where is flagella in spirochetal ultrastructure? How does it move?
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- inside (endoflagella)

- pairs that overlap

- moves by internal rotation- entire body rotates

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Spirochetosis baceria
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Treponema spp. (treponematosis)

Leptospira spp.

Boriella spp.

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Treponema bacteria (4)
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Treponema pallidum- syphillis

Treponema microdentia

Treponema denticole

Treponema vincentii- ANUG: acute necrotizing ulcerative gingivitis 

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Leptospira spp. is from what and causes what disease?
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from contaminated waters

causes weils disease

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Lymes disease bacteria
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Borrelia burgdorferi
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Nucleoid characteristics (7)
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1. Chromatin material

2. Electron opaque region by EM

3. Covalently closed double stranded circular DNA

4. Haploid

5. Multiple identical copies

6. Associated with cell membrane

7. Can be stained and seen by light microscopy

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mbp in nucleoid compared to eukaryotic cell
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mbp: million base pairs

nucleoid = 4.5

eukaryotic = 40 to 50

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Supercoiled DNA
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- compactness

- replication requires breaking one strand

- need enzymes: topoisomerase II/DNA gyrase to wind, topoisomeras IV to unwind

- unique to prokaryotes

- ex) E. coli is 2-3 nm big, but 1 mm of DNA fits

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Plasmid functions (3)
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1. extrachromosomal DNA (outside chromosome)

2. Non- essential genes

3. Replication

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Episomes
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can jump into chromosomes

considered to be extrachromosomal DNA

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Non-essential genes
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- gives advantages in environment

- pathogenicity islands- clustered together to form virulence mechanism

ex) having an extracellular matrix

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2 types of replication in plasmids
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Relaxed: have necessary information to replicate itself

Stringent: replicated with bacterial chromosome present

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Types of plasmids (3)
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1. Engineered genes for genetic engineering workbench

2. Virulence plasmids for pathogenicity islands

3. R (resistance) factors- genes that inactivate antibiotics

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R plasmids
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- R factors (whole plasmid) can be transferred to other bacteria

- Self transmissable (itself) vs. mobilizable (help)

-  R factors are not limited to antimicrobials

- All linked, 6-12 antibiotic resistance

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RTF
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resistance transfer factor

- genes necessary for replication

- conjugation

- resistance to antibiotics

- resistance to elements: antimony, arsenic, mercury, lead

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Ribosomal function
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protein synthesis

joining of amino acids

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Ribosome ultrastructure
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70S: prokaryotic, 30S + 50S

80S: eukaryotic

- differences are targets of antibiotics

- higher number = faster to settle, higher density

- highly conserved rRNA and protein

- significance in medicine

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Endospore details (4)
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1. produced by specific genera: bacillus spp. & clostridium spp.

2. Resistance structure: no reproductive value, resistant to extremes

3. Produced under threatening environmental conditions and complex developmental program

4. Long state of dormancy

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Bacillus & Clostridium spp. examples (4)
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Bacillus anthracis

Clostridium botulinum- food exotoxin

Clostridium tetani- tetanus

Clostridium perfringens - gas gangrene

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Sporulation and germination
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s: formation of endospore, low C/N amount

g: exit dormant stage and create vegetative cell by cortex cracking

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Identification of endospores (5)
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1. Position

2. Size

3. Shape: central/metacentric, subterminal, terminal

4. Laminated appearence

5. Unique chemical compostion

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Endospore stain and common location
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stain: schaefer-fulton

location: soil

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Gonnorhea bacteria
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Neisseria gonorrhoeae
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