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172 Cards in this Set
- Front
- Back
Spherical bacteria are called?
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coccus
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rod-like bacteria are called?
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bacillus
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what are the types of rod-like bacteria?
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1. filamentous
2. coccobacilli 3. fusiform |
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bacteria that are snake-like or corkscrew in appearance are called?
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spirillum
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new bacterial growth in planes at 90 degrees are called?
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clusters
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new bacterial growth in planes at 180 degrees are called?
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chains
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what is an example of a bacteria which growth occurs in clusters?
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staphylococci
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what is an example of bacteria where growth is in a chain?
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stretocci
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what is the importance of gram staining?
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predicts how organisms will respond to antibiotics and the pathogenicity of the organism
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a bacteria that is gram positive has what color?
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purple because its thick peptidoglycan layer binds crystal violet
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an bacteria that is gram negative has what color?
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pink/red because crystal violet is washed off due to a thing peptidoglycan layer and red safranin counterstain shows up instead
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gram staining does not work well on bacteria which are in what condition?
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starved
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gram staining does not work for which two types of bacteria?
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1. those without peptidoglycans
2. those with a thick lipid coat |
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what is the bacterial cell wall composed of?
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peptidoglycans
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which antiboitics result in premature release of aberrant protein and are bactericidal?
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aminoglycosides
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which antiboitics prevent polypeptide elongation, are bacteriostatic, and bind at the 30S subunit?
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tetracyclines
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which antiboitics prevent polypeptide elongation, are bacteriostatic, and bind at the 50S subunit? (3)
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1. macrolides
2. lincosamides 3. chloramphenicol |
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which antiboitics inhibit the formation of initiation complex at 30S subunit, are bacteriostatic, and bind to the 50S subunit?
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oxazolidinones
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what secretes the peptidoglycans of the bacterial cell wall?
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the cytoplasmic membrane
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what is the antibiotic active on gram-positive cell membranes?
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daptomycin
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what are the invaginations of the plasam membrane in prokaryotes which may serve to increase surface area for respiration and secretion as well as provide regions for DNA replication and segregation?
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mesosomes
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does a gram neg. or pos. have a outer membrane?
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only gram negative does
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what are the acids contained in the thick peptidoglycan layer of gram-positive cells?
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1. teichnoic acid
2. lipoteichoic acid |
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what is present in many body fluids which is capable of breaking down the gram positive peptidoglycan layer?
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lysozyme
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how does the body begin an immune response against invading gram positive cells?
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the innate immune response can recognize the the thick peptidoglycan layer and cause cytokine release which then activated the adaptive immune response
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what is the function of teichnoic acid and lipoteichoic acid for gram positive bacteria?
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cell adhesion
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how do teichnoic acid and lipoteichoic acid in gram positive bacteria betray there presence to the immune system?
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they are recognizable by the innate immune system (cytokine response) and are antigenic (cause formation of antibodies)
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what is the function of the peptidoglycan layer in gram positive cells?
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provide support and osmotic stability
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what is the protein in S. pyogenes which helpes prevent phagocytosis of the bacteria?
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M protein
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where is the M protein found in S. pyogenes?
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in the peptidoglycan layer
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what is the basis of serological classification for streptococcie?
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presence of polysaccharide antigens associated with the gram positive peptidoglycan layer
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which sp. is the only one to have sterol in the cytoplasmic membrane?
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Mycoplasma sp.
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where are mesosomes located?
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in the cytoplasmic membrane
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goind from the extracellular space inward, describe the layers passed through in a gram negative cell?
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1. outer membrane
2. periplasm 3. cytoplasmic membrane |
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where is the peptidoglycan layer located in gram negative cells?
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immediately external to the cytoplasmic membrane, but under the periplasmic space
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what are the acids contained in the peptidoglycan layer of the gram negative bacteria?
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the don't have any
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describe the functions of the periplasmic space? (3)
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1. contains metabolically active regions
2. contains hydrolitic enzymes involved in metabolism, virulence, and antibiotic resistance 3. contains proteins for sugar uptake |
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how does having a outmembrane help gram negative cells? (3)
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1. blocks macromolecules such as lysozyme
2. maintains bacterial structure 3. protects bacteria from harsh conditions |
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what aids in the recognition of gram negative receptors that is found in the outer membrane of gram negative bacteria?
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toll-like receptors in patterns recognizable by innate immune cells
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describe the properties of the inner and outer leaflets of the outer membrane bilayer?
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inner is like a normal bilayer, but outer is amphipathic because it has lipopolysaccharide molecules dispersed among the posphate head groups
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what are the sites at which the outer membrane is bound to the cytoplasmic membrane in gram negative cells?
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adhesion sites
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what attaches the outer membrane to peptidoglycans?
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lipoproteins
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what class of antiboitics targes the outer membrane of gram negative antibiotics?
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polymyxins
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what allow for dissusion of smaller hydrophilic molecules through the outer membrane of gram negative bacteria?
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porin protiens
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what are the 3 parts of the LPS component?
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1. Lipid A
2. Core polysaccharide 3. O antigen |
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which part of the LPS component contains endotoxin activity?
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Lipid A
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what is the bacterial capsul made of?
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loose polysaccharide layer
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what is the main purpose of the "slime layer" for bacteria?
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acts as an antiphagocytic virulence factor for extracellular bacteria and also may play a minor role in adhesion
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how does the body handle the bacterial capsul?
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it can create antibodies against the capsul and therefor initiate phagocytosis
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how are flagella anchored in the bacterial membrane?
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by a hook and basal body
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what is the driving force for flaggelum?
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membrane potential
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what are the hairlike structures on the external surface of cells?
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fimbriae
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what are the protein subunits of fimbriae called?
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pilin
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what is the main function of fimbriae?
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adhesion - very important for virulence
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what is the plasma encoded structure the promotes the transfer of genetic material between bacteria via conjugation?
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F (sex) Pili
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what is the key adhesion molecule for E. coli in adherence to uroepithelial cells
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P fimbriae
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people are more likely to develope reccurent UTI's when the express higher levels of what on blood cells?
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P antigen
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where are the precursors for peptidoglycans made?
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cytoplasm
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how are the cytoplasmic precursors of peptidoglycan transported across that bacterial membrane?
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bactoprenol
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how are cytoplasmic precursors of peptidoglycans attached to preexisitng peptidoglycans?
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activated with high energy posphate bonds
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what are the repeating units of peptidoglycans?
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NAG and NAM
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what joins adjacent rows of NAG-NAM-NAG-NAM-etc... together?
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amino acid bridges
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what projects of of NAM?
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a tetrapeptide
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what connects the tretrapetide chains extending from NAM?
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pentaglycine bridge?
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of the AA's of the NAM tetrapeptide, which is used to form a bond to the the next peptidoglycan?
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the 3rd AA is critical for transpeptidation
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how many amino acids are there on the chain sticking off of NAM before transpeptidation?
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5
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what are the last two AA in the chain sticking off of NAM before tramspeptidation?
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D alanine
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what is the antibiotic which binds the 5th AA (D-alanine) and stops peptidation from occuring between peptidoglycans?
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vancomycin
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vancomycin can only work against which bacteria, gram positive or negative?
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gram positive
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describe the 3 steps in peptidoglycan synthesis?
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1. formation of peptidoglycan precursor in cytoplasm (NAM)
2. attachment and transport of NAM by bactroprenol and the addition of NAG 3. translocation of disaccharide pentapeptide precursor outside of cell and attachement by transpeptidation to exisitng peptidoglycans |
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what is the name of the family of enzymes which facilitate transpeptidation and removal of 5th AA (D-alanine)
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Penicillin Binding Proteins
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what antibiotic irreversibly binds PBP's?
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beta lactam antibiotics
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how do cell wall-active antibiotics take advantage of of a bacterial cells own autolysins?
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the weaken cell walls by stoppin transpeptidation and the autolysins keep breaking down the cell walls which eventually causes the bacteria to lyse
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what triggers binary fission?
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DNA replication in bacteria
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how are mesosomes involved in binary fission?
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they hold onto the chromosome copies so when cells divide a copy is held into each half
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what is necessary for septum formation in binary fission?
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peptidoglycan formation over invaginations of the plasma membrane which occurs via transpeptidation of peptidoglycans
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drugs that inhibit peptidoglycan formation cause what to happen when the cell undergoes binary fission?
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long rodlike cells that are the result of chromosomal replication without cell division because cells could not complete the septum
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what are the two bacteria that genetically lack a cell wall?
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mycoplasma and ureaplasma
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what are the two bacteria which lack a cell wall?
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mycoplasma and ureaplasma
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what abnormal molecule is contained in the cell membranes of mycoplasma and ureaplasma that is not found in other bacteria?
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sterol
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what antibiotics in ineffective against mycoplasma and ureaplasma bacteria?
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ones that target cell walls
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how do some bacteria escape antibiotics which target cell walls?
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they temporarily remove cell walls until antibiotic is gone then they regrow them and recolonize
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which bacterial type (gram- or gram+) produce spores?
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gram+
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which gram+ bacteria produce spores?
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clostridium and bacillus
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where does the full set of chromosomal information contained in a spore come from?
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origina chromosomes are replicated and the replicated ones go into the spore and the originals are degraded after spore formation
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what happens to the newly formed spore just after the septum is completed?
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it is engulfed by bacteria that made it and peptidoglycans are secreted onto its surface
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what are the iron sequestering proteins of bacteria?
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siderophores
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what are bacteria which can grow in oxygen and without oxygen?
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facultative anaerobes - have multiple metabolic pathways which allows for this to happen
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what helps aroebic bacteria survive oxygen radical formation during respiration?
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supreoxide dismutase and catalase
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bacteria that derive energy from oxidation of metals are called?
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chemotrophs
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describe the energy source for most human pathogens?
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metabolism of sugars, fats, and carbohydrates
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what is the product of fermentation?
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ethanol, ATP, and NADPH
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the nucleic acids that are products of the pentose phosphate shunt are known as?
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purines
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what drugs interupt the production of thymine? (2)
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sulfamide antibiotics and trimethoprim
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what is the action of sulfamide antibiotics and trimethoprim?
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stops the production of tetrahydrofolic acid
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what is the action of rifampin?
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binds RNA polymerase and halts transcription which makes the bacteria vulnerable to other antibiotics
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what serves as the docking site for RNA polymerase alone a strand of DNA?
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sigma factor
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what are the antibiotics which bind the 30s subunit? (2)
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1. aminoglycosides
2. tetracyclines |
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what are the 4 antibiotics which bind the 50s subunit?
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1. cloramphenicol
2. macrolides 3. lincosamides 4. oxazolidinones |
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are antibiotics which bind the 50s subunit primarily bacteriostatic or bactericidal?
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bacteriostatic
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in what phase are bacteria most vulnerable to antibiotic action?
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exponential growth phase
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what is the direction of extension of the lagging strand of DNA?
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5' -> 3'
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toperisomerase is the target of which antibiotic?
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quinolones
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are quinilones bacteriostatic or bactericidal?
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bactericidal
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a transition base pair mutation involves?
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prurine for purine or pyrimidine for pyrimidine
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a travservsion involves what?
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purine is substituted for pyrimidine and vice versa
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what is a null mutation?
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extensive recombination or trasnpositional events leading to the destruction of gene function
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what is the DNA repair that is independent of template and involves replication across stops that would normally halt other polymerases?
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SOS response
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what is the last-ditch effort to repair broken DNA without a template that involves replacing missing DNA with random sequence?
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error-prone repair
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what is the term used to describe the passing of genes between bacteria which can involve resistance and virulence genes?
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horizontal gene trasnfer
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how does genetic material transferred to a bacteria come to be expressed by that bacteria?
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homologous and non-homologous DNA recombination allows information to enter the genome
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plasmids which are unable to integrate into chromosomes are termed?
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episomes
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what are some examples of enzymes that recognize special sites on DNA that allow for non-homologous recombination?
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transposases and integrases
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what DNA segments which can move around in DNA sequences be be any type of recombination? (jumping genes)
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transposons
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what are transposons flanked by?
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insertion sequences
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what is the simplest transposable element?
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the insertion sequence
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recombination is mediated by enzymes called?
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site-specific recombinases
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what allows for rapid acquisition of antibiotic resitance genes in bacteria?
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site-specific recombination involving intergrases
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what are large chromosomal regions containing genes which code for multiple virulence factors called?
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pathogenicity islands
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what is necessary to build a pathogenicity island?
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integrases and non-homologous recombination
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what is that act of a living bacteria binding and taking up DNA from a dead bacteria?
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transformation
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what is necessary to keep DNA aquired by transformation intact within the recipient cell?
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recombination of that DNA in recipient genome
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what is the important bacteria that has gained penicillin resistance via trasnformation?
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normal penicillin resistance strep from the mouth gave streptococcus pneumoniae penicillin resistance
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what is the term that refers to the passage of DNA directly between cells during contact? (bacterial sex)
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conjugation
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what allows for the transfer of DNA between the cells during conjugation?
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mating bridges
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what does the term self-transmissible refer to?
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the ability of a plasmid to form a mating bridge from the proteins encoded in it
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what does the term mobilizable refer to in regards to conjugation?
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a plasmid which can cleave itself at the OriT and make use of a mating bridge established by a sel-transmissible plasmid
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the state of F factor, F- means what?
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no self-transmissible plasmid
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the state of F factor, F+ means what?
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autonomous plasmid with plasmid genes only that is capable of self-replication
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the state of F factor, Hfr means what?
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the plasmid is incorperated into a chromosome
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the state of F factor, F' means what?
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autonomous plasmid with some chromosomal genes and capable of self-replication
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gram negative organisms use which structures to facilitate conjugation?
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sex pilus
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gram positive organisms use which structures to facilitate conjugation?
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surface adhesion molecules
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what is conjugation dependent on?
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the presence of a conjugative plasmid
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what are the essential components a conjugative plasmid must contain? (2)
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1. ability to make sex pilus
2. ability ot initiate DNA synthesis at transfer origin (OriT) |
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tetracycline resistance was first recognized to be transferred by?
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transposons
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describe the prevelance of replication of trasnposons?
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not often replicated so donor looses transposon
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what are the 2 possilbe outcomes of a bacteriophage attack on a bacteria?
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1. lytic infection
2. lysogenic infection |
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describe generalized transduction?
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occurs during a lytic infection when produced bacteriophages accidentally incorperate bacterial DNA and distribute is to other bacteria
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describe transduction via lysogenic infection?
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Phage integrates in host genome, but eventually excises itself and causes cell lysis. If excision is sloppy it can include bacterial DNA which is transferred to other bacteria upon infection.
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what type of bacterial genes are commonly tranduced via lysogenic transduction?
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toxin genes
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what is a major nosocomial (hospital infections) pathogen that is normal in gut flora, but causes UTI's skin and soft tissue infections, and bloodstream infections?
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enterococcus sp.
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which bacteria is a colonizer of nares, skin, GI tract, GU tract with a sixty year history of antibiotic resistance?
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staphylococcus aureus - highly virulent and invasive extracellular pathogen
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how does MRSA become vancomycin resistant?
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vancomycin resistant enterococcus passes resistance plasmid via conjugation to MRSA which then becomes incorperated into stable plasmid in MRSA to make MVRSA
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the ability of an organism to cause disease is known as?
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pathogenicity
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a quantitative measure of pathogenicity is called?
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virulence
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properties of an organism that enable it to establish itself and enhance ability to cause disease are called?
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virulence factors
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describe quorum sensing?
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corrdinated expression of virulence genes in response to overpopulation of bacteria that allows a certain bacteria to fight off others
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what are some examples of virulence factors under quorum sensing control?
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expression of exopoteases, exotoxins, siderophores, and biofilms
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what are the proteins that are expressed by Gp. A strep which protects it from phagocytosis?
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M proteins
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what prevents bacterial from bing removed from a surface during washing?
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fimbrae adhesins
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which kind of bacteria (- or +) produces type I exotoxins?
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gram positive
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what is a type I exotoxin?
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superantigens
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what is toxic shock caused by?
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staph aureus exotoxins
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toxin-mediated diarrhea is caused by?
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staph aureus exotoxins
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scarlet fever, necrotizing fasciitis or toxic-shock are all caused by which bacteria?
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strep pyogenes
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what is the action of Type II toxins?
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membrane disrupting
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what are the 2 types of exotoxin?
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pore-forming and phospholipases
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what bacteria releases a phospholipase that lysis blood cells and endothelial cells resulting in massive hemolysis and bleeding?
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Clostridium perfringens
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what is the most serious presentation of a Clostridium perfringens infection?
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myonecrosis (gas gangrene)
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describe the structure of Type III exotoxins?
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A-B structure where A is toxin and B is binding protein
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what is an example of an A-B toxin?
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diptheria toxin
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what does diptheria toxin do?
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stops interaction between tRNA and mRNA meaning all protein production stops
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how lethal is diptheria toxin?
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only one molecule is sufficient to kill one cell
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how do vaccines against diptheria toxin work?
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they help the body make antibodies which bind the B part of the A-B structure to keep it from binding to cells
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what are the main bacteria (gram - or +) that use type IV toxins?
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gram negative
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what actually causes the damage done to tissue at the site of type IV exotoxins?
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inflammatory cell that send out degrading enzymes into the bystander tissue
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what is the result of Type IV exotoxin release in tissues?
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granulomas
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describe immunologic damage to tissues?
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cross-reactive antibodies are made to a pathogen that also are able to recognize self-tissue and attach to it
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the cross-reactive antibodies responsible for heart damage with rheumatic fever are originally made for?
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strep pyogenes
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the cross-reactive antibodies responsible for joint, CNS, and blood antigens reactionsr are originally made for?
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mycoplasma pneumoniae
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what disorder is characterized by creation of antibodies which react with gangliosides in the nervous system
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Guillain-Bar syndrome
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