Micro Bacteria – Flashcards
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| prokaryotes: type of organisms, size, metabolism, contents of organisms, nuclear status, cell division |
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| bacteria small aerobic or anaerobic no organelles has cell wall circular DNA no exocytosis or endocytosis chromosomes pulled by attaching to membrane in cell division mostly unicellular |
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| eukaryotes: types of organisms, size, metabolis, contents, nuclear status, cell division |
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| protistts, fungi, plants,animals larger aerobic or anaerobic many organelles internal cytoskeleton, no cell wall linear DNA in nucleus needs exocytosis and endocytosis cheomosomes pulled by cytoskeleton attachments in cell division unicellular and multicellular no cell wall (except for chitin in fungi) |
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| how are prokaryotes classified |
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| phenotypie: stain, shape, metabolism, serotypes |
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| what are some signs that you can diagnoise a bacteria, parasite, inappropirate antibiotic use, or invasive organism |
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| bacteria: takes time to see toxins parasite: chronic, weeks, seen in outbreaks inappropirate antibiotics; clostridium overgrowth leads to toxins invasive: blood mucous, fever |
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| selective bacteriological growth medium: purpose, how it works |
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| uses bacteria with antibiotic resistance that antibiotic in the medium to make sure it is the only microbe that grows |
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| differential bacterological growth medium: how it works, goal |
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| uses indicator to distinguish one bacteria from another |
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| blood agar: how it works |
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| uses mammal blood to nourish bacteria |
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| macConkey agar: goal |
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| grow gram negative bacteria and differentiate them for lactose fermentation |
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| microaerophillic agar: composition purpose |
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| for campylobacter 10% CO2 |
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| xylose lysine deoxycholate agar (XLD): what organs does it show, in what color, what is pH, composition |
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| samlmonella: red colonies, some back centers shigella: red colonies choloforms: yellow to organg colonies pseudomonas aeruginosa: pink, flat, rough colonies pH 7.4 pink or red due to phenol red indicator |
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| how does staining a cell work |
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| stains cell wall no cell wall, no staining |
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| gram stain: what does it stain, what dosent it stain, what do the colors indicate |
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| stains peptidoglycan layer of gram positive cannot stain LPS layer of gram negative pink: gram stain negative blue: gram stain positive |
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| acid fast stain: what does it stain, what do the colors indicate |
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| stains LPS or mycolic acid layers pink: acid fast positive blue: acid fast negative |
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| silver stain: what does it stain, what is the benifit of this stain |
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| coats outside of organism can be used for an organism in a tissue |
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| dark field, what is it |
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| way to look at bacteria without staining |
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| what does zoonotic mean |
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| intrasepcies infections possible |
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| describe the genetic material of bacteria, what does it contain, shape, location, other options |
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| circular DNA no intros, contious coding in nucleoid region plasmids: extra chromosomal DNA |
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| what organelles do bacteria have, where are the cell processes done |
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| ribosomes 70S (30S and 50S) the rest of the functions are done in cell membrane: mitochondrial functions for example, helps in cell division |
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| cell membrane: composition, how it is different from outs, function |
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| no sterols: except mycoplasma which has cholesterol transports metabolites and wastes passivly, functions of organelles it is lacking in cytoplasm |
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| what targets the cell membrane |
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| phenolic difinfectants, polymyxin B |
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| what targets bacteria ribosomes |
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| aminoglycosides macrolides lincosamides tetracyclines chlorampheicol |
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| bacterial cell wall shapes (7) |
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| cocci: sphere bacilli: rod spirilla: helical filamentous coccobacilli: small rod fulsiformL long rod vibro: boomerang |
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| what bacteria cell wall shapes are only in gram negative bacteria |
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| sprilla fulsiform vibro |
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| what are fulsiform shaped bacteria found |
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| pharyngeal and GI |
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| what bacteria dont have a cell wall |
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| mycoplasmas, ureaplasmas |
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| how is the cell wall different in gram positive and negative bacteria |
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| thinner in gram negative |
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| what is the composition of the cell wall |
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| peptidoglycan: N-acetylglycosamine, N-acetylmurmaric acid cross linked pentapeptide bridges techoic acid and lipoteichoic acid penicillin binding proteins |
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| what targets pantapeptide birdges |
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| beta lactam antibiotics |
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| techoic acid: where is it foind, what does it do |
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| adhesion only in gram popsitive peptidoglycan wall |
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| penicillin binding proteins: where are they, what do they do, what targets them |
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| on most bacteria, bind penicillin, targeted by beta lactam antibiotics |
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| is the cell wall hydrophobic or hydrophillic, why, what does this provide for the bacteria, what is the down side |
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| polar, hydrophillic due to polar AA allows gram positive bacteria to resist bile not resistant to the lysosome |
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| why is the cell wall antigenic |
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| peptidoglycan causes cytokine response |
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| what is the cell wall targeted by |
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| beta lactam and glycopeptide antibiotics |
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| composition of the LPS layer and structure |
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| lipopolysaccharides, lipoproteins that connect to peptidoglycan layer Ca and Mg help hold together O antigens lipid A chain |
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| o antigens: locations, what do they do, purpose for us |
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| on LPS adhere to epithelial cell receptors and endotoxin used for serology |
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| lipid a chains: function, composition |
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| endotoxin: induces macrophages and cytokines (IL-1, 6, TNF) causing inflammation disaccharide diphosphate and FA composition |
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| how is the gram negative capsule different in nisseria |
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| lipooligosaccharide glycoproteins fewer o antigens |
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| periplasmic space: lication, function, contents |
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| between peptidoglycan and membrane in gram negative preliminary digestion of large molecules with collagenas,e hyaluronidase, nucleases beta lactimase to stop the antibiotic |
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| what is ompA |
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| pore through gram negative capsule opening |
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| is the gram negative capsule hydropillic or hydrophobic, why |
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| hydrophillic: most of the membrane, protects against bile hydrophillic: due to lipid component so both |
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| what are porins, where are they, what do they do |
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| hole in LPS that is hydrophillic allos nutrients, AA, and large molecules |
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| what is the function of the LPS |
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| protection against antibiotics, gastric juices, inflammatory response, alternate complement pathway |
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| why is the LPS layer antigenic |
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| peptidoglycan and LPS activate immune system causing inflammation, also a virulance factor o antigen and lipid A |
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| what damags the LPS layer |
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| polymyxin |
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| why is mycobacterium different, what is the outer layer, what is the function of the layer |
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| gram negative, has peptidgoglycan layer but it is structured a little different outer envelope has mycolic acids; waxy, resistance to dring adjuvant activity: promotes immune response |
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| what is a PAMP, where is it located |
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| pathogen associated molecular pattern recognized by TLR receptors on phagocytes and dendritic cells located on lipolysaccharide capsules, peptidoglycan, teichoic acid, flagella, fimbrae, bacteiral DNA, LPS |
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| capsule: function and composition |
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| adherance and anti-phagocytic. located outside of cell wall, peptidglycan and LPS polysaccharide and k antigens |
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| slime layer: where, what is it made of, function |
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| external to cell wall and outer envelop kind of a capsue made of big glycoproteins tissue specific, contributes to biofilm protects against phagocytosis and antibiotics |
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| 3 examples of bacteria with a slime layer and where |
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| sterp mutans on teeth staph epidermis on heart valves and prostetics pseudomonas aeruginosa on respiratory tract |
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| flagella: function, stimuli |
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| assist in adhesion and biofilm formation type III secretion injections into host move away from phagocytes (virulence) respond to chemical stimuli, no ATP needed |
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| what are the three ways flagella can be arranged |
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| polar: single lophotrichous: in tufts peritrichous: all over cell surface |
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| what is the structural component of flagella, serology, and immuno reaction to iy |
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| flagellin proteins h antigens trigger cytokines TLR5 |
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| what are the 4 adhesion molecules |
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| m protein of streptococci and s. pyogenes techoic acid on gram positive serologica varients AltC and TLR pilli/fimbrae |
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| functions of pilli, types, how does it work |
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| prevent phagocytosis if many of them can change antigens to avoid immune response via gene recombination sex pili: allow for attachent to other bacteria for conjugation common pili: allow for attachment to host via adhesins interactions |
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| how can things move across a bacterial cell wall |
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| facilitated diffusion: carrier moves compound to equalize cellular concentrations active transport: energy used to increase cellular concentrations oxidative metabolism: occurs in cell membrane periplasmic space digestion first |
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| what are the 7 nutritional requirements of bacteria, what do they produce inthe cell |
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| C: organic compounds O: organic compounds, e- acceptor N: AA, nucleotides, coenzymes. comes from NH4 H: organic compounds P: nucleotides, LPS, phospholipids Sulfur: AA, coenzymes K: cation, cofactor, comes from inorganic sources |
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| what are the 4 different types of metabolism |
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| heterotrphic anaerobic facultative anaerobe anaerobic |
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| heterotrophic: how it works |
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| get energy from molecules to make ATP |
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| anaerobic: how does it work, what requirements does a organism need to do this, example bacteria |
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| final e- acceptor is O2 have to deal with ROS: superoxide dismutase, peroxidase, catalase glycose -> 38 ATP pseudomonas aeruginosa |
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| obligate aerobe requirements |
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| needs O2 and has ROS enzy,es |
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| microaerophile: requirements |
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| can handle O2, has a few ROS enzymes |
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| facultative anerobe: requirements |
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| with or without O2 has ROS enzymes |
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| anaerobic metabolism: how does it work, how is the energy produced different, example |
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| final E- reeptor is inorganic molecule (Fe, SO4, NO3) clostridium bacteroids produces fewer ATP |
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| what are the different kinds of anaerobic metabolism |
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| fermentation secondary fermemtation obligate anaerobe |
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| obligate anaerobe requirements |
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| cannot have O2 present, no ROS enzymes |
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| fermentation: how it works, example |
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| glycose is turned into lactic acid, CO2, or ethanol E. coli |
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| secondary fermentation: how it works |
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| uses pyruvate from the first to make more energy |
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| what might an aerobe need special in its growth medium |
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| need more CO2 if microaerophillic need special temp and medium concents |
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| what is the clinical significance of metabolism |
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| target of antimicrobials helps perdict where organisms will infect helps identify the microbe |
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| what antimicrobials targer bacterial metabolsim |
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| disinfectants, antiseptics, heavy metals antimicrobials: sulfoanides, aminosalicyclic acid, dapsone, trimetroprim |
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| how does metabolism perdict infection location and determine antibiotics |
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| Gi has little O2 and may have anaerobes some antibiotics dot work where there is oxygen |
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| how does metabolism help identify the microbe |
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| screen for enzyme presence: catalase for staph, coagulase for staph aureus, oxidase metabolic profle: combo of metabolic reactions like a chem profile in humans |
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| how does coagulase work for staph |
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| takes fibrogen and splits into fibrin coating itself to confuse pathogen |
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| what is the rate of bacterial growth dependent on, what is the exception |
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| nutritional status and enivornment mycobacterium will also grow slow |
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| what are the phases of bacterial growth, what happens in them |
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| lag: slow grwoth when introduced to a new enivornment exponential/log: population doubles at a constant rate stationary: slow growth due to nutrient depletion and toxin build up death: decline of cell growth after stationary phase |
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| DNA replication: how does it work, what machine does it, what enzymes |
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| begins at the origin of replication multienzyme replication complex binds to origin and begins unwinding and seperating DNA with topoisomerases and gyrases DNA polymerase duplicates adding deoxyrnucleotides replicating bi-directionally and proofreading topoisomerases and gyrases fold DNA into compact form |
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| what does fluroquindine target |
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| topoisomerases and gyrases |
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| what is the general process of bacterial cell division, account for the wall |
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| segregation of genomes formation of septum in middle of cell: cytoplasm invaginates, petidoglycan and outer gram neative capsule have ingrowth |
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| what are the classifications of how bacteria look when they are dividing |
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| sterptococci: dividing in one plain appear chained diplococci: dividing in one plain appear paired saphylococci: dividing in multiple chains appear clustered filamentous |
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| what attacks bacterial cell division |
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| antimicrobials; quinolones (ciproflaxin and levoflacin) stop DNA unwinding |
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| what are the steps of bacterial transcription |
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| DNA dependent RNA polymerase uses sigma factor to find a promoter polymerase binds promoter which tells the polymerase how fast to transcribe polymerase copies DNA into RNA transcript by adding ribonucleotides promoter raches termation site which stops transcription a polycistrinic operon with many genes on one strand is made |
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| how is the DNA dependent RNA polymerase in gram positive bacteria different |
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| gram positive bacteria have many sigma regions to find different promoters whih allow the same polymerase to find different genes |
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| how does a promoter tell the polymerase how fast to go |
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| promoter DNA sequence supercoiling DNA regulatory proteins by the promoter |
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| what does rifampin target |
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| antimicrobial bacteriacidial that stops RNA polymerase |
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| how does a termination site work |
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| coded with uracil followed by repeat sequence a loop structure kicks the polymerase off its track rho termination protein |
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| how does translation begin |
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| ribosome binds shine dalgarno sequence and begins translation at start codon (AUG) which lines up with tRNA anticodon and adds a AA vi condensaion |
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| what antimicrobials terminate protein synthesis |
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| erythromycin, terracyclines |
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| what are the stop codons |
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| UGA, UAA, UAG |
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| why does gene expression need to be regulated |
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| for adaptation to the enivornemtn and so energy isnt wasted on viruence factors that aernt needed |
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| what are the ways to regulate gene expression |
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| alter effciency of RNA polymerase binding to promoter, two component regulators, activator cascade, quorum sensing |
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| how is RNA polymerase altered |
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| temp and o2 changes change supercoiling which alters promoter region regulatory protein on operator regions on DNA activator proteins increase rate repressor proteins inhibit transcription |
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| what is a two component regulator, what does it do |
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| one protein acts as sensor to detect enivornmental changes, one protein acts as DNA binder to activate transcription. turned on when phosphorlyated |
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| what is a activator cascade, how does it work |
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| signal activates one gene whose product activates epression of another gene which produces the desired product (virulence factor) |
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| quorum sensing regulation: what is it, how does it work |
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| gene transcription is activated in response to bacterial concentration bacteria produce signaling compound which builds up as more arrive when there is enough bacteria coming together, it can bind receptors and initiate transcription |
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| what is the lac operon doing in a normal situation |
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| glucose is the preferred food source but bacteria can use lactose if needed catabolite repression: unless tjere is no glucose the lac operon is off, no genes for lactose metabolism are made |
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| cAMP dependent catabolite activator protein (CAP): what does it do, how does it work |
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| activated when cAMP is bound cAMP is low when glucose is present. CAP does not bind dna so there is no lactose metabolism proteins made cAMP is high when glucose is gone. CAP is activated and binds lac operon DNA allowing production of lactose metabolism proteins |
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| lactose repressor protein (Lac-I): what does it do when lactose is and isnt present |
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| without lactose it binds to lac operon promoter so polymerase cannot bind and lactose metabolism proteins cant be made when lactose is present allolactose binds lac-i removing it from the promoter allowing polymerase to attach and lactose metabolism proteins to be made |
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| what are the mobile genetic elements or ways of transporting genetics |
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| plasmids virulent bacteriophages temperate bacteriophages transposition pathogenicity islands intergrons |
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| what are the types of plasmids |
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| broad host range restricted |
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| broad host range plasmid: location, function |
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| replicate in many species used to transfer genes across species to study gene products or make larger quantities of products |
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| restricted plasmids; location |
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| only replicat within host |
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| restricted plasmids: replicatio process/differences |
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| self-replicating circular dsDNA not all replicated bi-directionally, some have single replication fork larger plasmids have fewer copies made of them transferred by conjugation |
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| what are the gene products of plasmids |
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| genes for more replication and transfer resistance genes: to antimicrobials, especially on R plasmids virulence genes: toxins and proteins for virulence |
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| virulent bacteriophages: what are they, how do they reproduce, what is the structure |
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| bacterial viruses that survive outside and inside the cell reproduction leads to bacterial cell destruction protein coat (capsid) and nucleic acid, possible tail for infection |
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| temperate bacterophages: how do they work |
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| they could act like a regulat bactriophage or do lysogeny |
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| explain lysogeny |
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| development of prophage: cirus inserts the viral DNA into the bacterial chromosome 2. prophage conversion: new characteristics appear when prophage is translated 3: enivormental stimulus inactivates bacteriophage repressior that is maintaing the condition, viral DNA is excised, vital proteins and genetic material made, cell lysis and viral release |
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| what is transposition, how is it regulated, what is the function |
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| DNA sequences jump from one site on DNA molecule to another in the same cell specific site recombination: movement is directed by short DNA sequences ont he mobile element used for homologous reombination can cause deletions in the functional gene in the process |
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| what are the types of movement involved in transposition |
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| intron and transposition |
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| explain the process of intron transposition |
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| intron encodes transposase (tn5) enzyme which is needed for transposition froom one DNA site to another for location of the nw DNA site a portion of the jumping sequence is duplicated durin transfer so there are repeat sequences on the ends of the DNA piece at the new site two intron sequences inserting near eachother would allow larger region to become transposable |
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| how does transposons work |
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| contain genes for transposition and other things (usually antibiotic resistance and virulence genes) Tn3/simple transposon allows for movement encodes resistance to beta lactams, move in single unit genes for transposition on the ends inversley oriented indirect |
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| what can transponins move between |
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| host genome to plasmid plasmid to plasmid plasmid to host genome |
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| what do pathogenicitity islands contain, where are they located |
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| contain groups of virulence genes often have introns with direct repeats on teh ends not found in non-pathogenic bacteria large and unstable genomic islands: DNA sequences tha tlook similar but lack genes for movement |
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| integrons: function, copsition, genes encoded |
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| use speficic recombination to get new genes no terminal repeat sequences has genes like transposons that carry genes for antibiotic resistance |
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| how does mutation happen |
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| errors in DNA replication mutagens (chemicals) cause dnA changes UV light radiation nucleotide base analogs mimic nucleotides in DNA synthesis but can pair mulriple with the opposite strand intercalating agents insert and distort DNA helix |
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| what are the types of mutation |
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| point mutation deletion replacement insertion inversion |
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| what is a point mutation, what is the result |
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| single nucleotide change can cause no change, AA substitution, or stop codon formation truncating the protein |
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| what are the defnces against genetic damage, how do they work |
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| direct repair: reverses or removes the damage. first line of defense excision repair; damaged strand is recognized and repair polymerization fixes it and ills teh gap with proper DNA complementary template recombinational repair: used after DNA is damages, cuts and pastes damaged areas |
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| what is recombination, what is the point |
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| new genotypes arrive when genetic material is transferred from one bacteria to another |
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| what are the methods of gene transfer |
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| transformation transduction conjugation |
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| what is transformation, how does it work |
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| taking up dNA fragments from related species across cell walls then combining it with homologous DNA via recombination (requires DNA to be lated) fragments come from cell lysis sit in the extracellular space exposed to destruction |
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| what DNA can be taken into a cell without recombination |
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| plasmid |
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| transduction: what types, between what |
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| ransfer of genetic material between the same species virulent bacreriophage mediated, temperate bacteriophage mediated |
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| explain how virulent bacteriophage mediated transduction works |
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| additional DNA is packaged into new virons (transducing particles) DNNA is incorporated into host genome via homologous recombination |
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| explain how temperate bacteriophage mediated transduction works |
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| as prophages enter the lytic cycle they incorrectly excise from their attachment site pulling som ebacterial DNA with them infection of recipient cell sllows the dna to homologously recombine in vicinity of viral attachment plasmids unable to transfer by this process due to specific chromosome prophage interaction |
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| what is conjugation, why is it food for resistance genes |
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| dna is transferred from one bacteria to another no recombination |
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| what is a tra gene, what is the function |
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| gene on conjugate pasmid that codes for sex pili to transfer dna via conjugation on large plasmids because it takes up lots of genetic space |
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| what are the types of f plasmids |
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| episomes integrated f episomes unintegrated f episomes mobilization |
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| episome: function |
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| fertility plasmid that integrates into bacterial genome via intron segments |
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| integrated F episome, how does it work |
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| duplication transfer process moves into regions of the adjacent genomic dna |
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| un integrated f episomes: how does it work |
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| mediate transferof genomic dna on hrg strain which do not completely transfer recipient does not become hrf and cannot be a conjugate donor |
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| mobilization plasmid |
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| non-conjugate and conjugate plasmid in the same cell being transferred together |
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| endospore: when does it form, where are they found, what are the contents, what are the structural changes |
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| formed when cell is unable to grow due to enivornmental conditions or lack of nutrients abundent in soils chromosome, ribosomes, proteins, and keratin like coat structural changes: complex multilayer coat surrounds cell, diplicolinic acid and Ca increase heat resistance |
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| what is the benifit of endosport, give example |
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| can remain viable for years and recover rapidly clostridum and bacillus can cause tetanus and anthrax |
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| biofilm: what is it, what is in it, what is the function |
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| colony of bacteria in their extracellular products (DNA, proteins, polysaccharides) bacterial slime layers contribute gene regulation swutches to biofilm set of genes creates compartments to protect susceptible organisms |
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| what are things on a bacteria antimicrobials target |
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| cell wall structure and synthesis cell membrane DNA and RNA replication (DNA gyrase, DNA dependent RNA polymerase) protein synthesis folic acid metabolism DNA structure |
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| what is the function of genomics |
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| perdicts antimicrobial effectiveness, facilitates identification via rRNA genes, resistance to antimicrobials, molecular epidemiology |
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| how can rRNA genes help with identification |
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| found in rRnA operon which has multiple copies throgh out the genetic material some sequences are conserved and show up on all bacteria some sequences are internally transcribed spaces and are only the same in closley related baceria |
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| how can molecular epidemiology help with identification |
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| phenotype and genotype are used to find relationships |
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| what are the approaches to detection of species |
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| PCR, nucleic acid probes, DNA microarray, gel electrophoresis, correlation of outbreaks, RFLP, mass spac, cytochromography |
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| PCRL functions |
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| rapid diagnosis of bacteria d viruses that are unable to be cultivated helps determine epidemiology measures viral load and AIDS forensic analysis and paternity testing detection of mutations diagnosis of disease (lymphome, leukemia) DNA/rRNA nucleotide sequencing mass multiplication of olifomer primers, nucleotides, and polymerases |
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| DNA microarray: fuction, process |
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| identify pointmutations and single nucleotide polymorphisms modified southern blod that detects DNA known probes are attached to a solid surface and fragmented dna/rna is added it binds to appropirate probe a label is added to visualize the bound probes |
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| RFLP: process, goal |
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| endonucleases cleave DNA/RNA at specific site fragments put into electric field and they migrate eihidium bromide is used to see them to detect migration distance compare known strands with unknown strand migration |
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| mass spec; goal, process, benifits |
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| determine molecule identity with mass to charge ratio rapid and cost effective |
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| chytochromography how does it work |
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| identifies organism by cell wall components (FA) |
