Microbiology Lab UTA - Final EXAM BRAND NEW!! (251+ QUESTIONS AND CORRECT ANSWERS) VERIFIED ANSWERS

Microbiology Lab UTA - Final EXAM BRAND NEW!! (251+ QUESTIONS AND CORRECT ANSWERS) VERIFIED ANSWERS Acidophiles - ANSWER-below ph 5.5 .Add 15 drops of Barrits Reagent A (alpha-napthol). MIX. Add 5 drops of Barrits reagent B (KOH) to same tube and mix well to oxygenate for 30 seconds. Vortex if you want. Incubate up to 1 hour to see result. - ANSWER-How to perform VP test .Advantages to using semi-solid media - ANSWER-To test oxygen requirements, to test motility. .Agar - ANSWER-linear polysaccharide polymer derived from agarose in red algae. .Alcohol - ANSWER-65-70% is most widely used skin disinfectant. .Alcohol/acetone mixture that dehydrates the cell, shrinking the cell wall. - ANSWER-What are decolorizers composed of and what do they do? .alkalophiles - ANSWER-above 8.5 .Anaerobic metabolism by - ANSWER-phosphoketolase pathway .Anaerobic respiration, where the terminal electron acceptor is an inorganic molecule other than oxygen - ANSWER-Nitrate reduction is an example of _____ .Antibiotics are - ANSWER-natural antimicrobial agents produced by microorganisms that inhibit or kill other microorganisms. .Antimicrobials - ANSWER-any natural/synthetic substance that kills MOs .antiseptics are - ANSWER-bacteriostatic agents .Antiseptics are - ANSWER-safe for tissues .Autoclave - ANSWER-sterilizes with steam at 121* C, pressure at 15 PSI for at least 15 min. Tested weekly to daily. .Autoclaving removes the free oxygen in the media. As the agar cools, oxygen diffuses and creates an OXYGEN CONCENTRATION GRADIENT ranging from aerobic to anaerobic. - ANSWER-Why is media sterilized using the autoclave? .Bacillus - ANSWER-What shape are Gram (-) cells? .Bacteria require water to maintain - ANSWER-cellular turgor pressure .Bacteria that produce tryptophanase hydrolyze tryptophan, a component of the peptone in the media, to produce the product indole - ANSWER-How is the presence of the enzyme tryptophanase tested for using the SIM media? .bacteriostatic agents - ANSWER-inhibit microbial multiplication without killing .Barritt's Reagents A/B - ANSWER-Reagents used for Voges-Proskauer test? .beads on a chain - ANSWER-Morphology of Streptococci .because they can't make cytocrhomes - ANSWER-Streptococci cannot carry out oxidative phosphorylation to ferment sugars .blue or black shiny slightly raised 1-2 mm colonies - ANSWER-Enterococcus spp. .Calculations for number of bacteria per ml - ANSWER-# of colonies x reciprocal of dilution of sample .Capsule / Glycocalyx - ANSWER-Thick, mucoid polysaccharide layer surrounding all bacterial cells. Prevents desiccation, guards against the host immune response, and aids in adhering to host cells. .Capsules resist stains, so basic crystal violet is applied to stain the interior of the cell while acidic India Ink stains the background. The capsule appears white. - ANSWER-Capsule Staining .Cell distortion, slide damage, and dilution issues. - ANSWER-What are the cons of heat staining? .Centrally, Terminally (end), Sub-Terminally (middle) - ANSWER-Where can endospores be located within a cell? .Chromatophore - ANSWER-Part of the molecule (chromogen) lending it color .Chromogen - ANSWER-positively charged and bonds to negative charge on bacteria .Clearing of Agar- complete - ANSWER-Beta hemolysis .Cloudiness around the stab line in the media usually indicates a positive result. - ANSWER-How is motility tested for in the SIM Media? .Coagulase production and mannitol fermentation correlates more with - ANSWER-pathogenicity .Coccus - ANSWER-What shape are Gram (+) cells? .Coliforms used as indicator organisms - ANSWER-E.coli, E. aerogenes .Colonies will grow on the Simmon's slant, but they will not change color. Still a POSITIVE RESULT - ANSWER-What result will occur if incubation is incomplete in a citrate test? .Colony Forming Unit (CFU) - ANSWER-Correct term for a colony .compound solutions - ANSWER-successive transfers .Converts fibrinogen to fibrin in blood plasma and clots - ANSWER-How does coagulase test work .convex - ANSWER-Morphology of a domed colony .crateriform - ANSWER-hole in convex colony .curled - ANSWER-wave pattern on margin .Decarboxylates ammonia - ANSWER-What does urease do in a cell? .Defined Media - ANSWER-Amount and components of every ingredient is meticulously detailed. .Denitrification, where NO3- is converted to N2/N2O. Indicated by the presence of air bubbles. - ANSWER-What must one check for before testing for nitrase reductase? .detects acetoin in the 2,3 butanediol pathway - ANSWER-The VP test .Determines whether the enzyme urease, which decarboxylates ammonia to raise the pH, is present. - ANSWER-Urea hydrolysis tests for what? .Differentiates between facultative anaerobes in discerning which organisms USE CITRATE as the sole carbon source and can ferment it TO PRODUCE PYRUVATE VIA CITRATE PERMEASE - ANSWER-What does the Citrate Test for? .Differentiates Enterococcus species from Streptococcus bovis group and other Streptococci - ANSWER-SF Medium .Differentiates for organisms that produce coagulase- the exoenzyme which is present in pathogenic S.aureus. - ANSWER-Coagulase test .Dilution Factor (DF) - ANSWER-a tracking system of the original number of bacteria present within the dilutions. .Disinfectants - ANSWER-kill most or all bacteria when making contact .Disinfectants are meant for - ANSWER-surfaces .E. Coli - ANSWER-gram negative non-spore forming rod, coliform, .Endospore - ANSWER-Dormant form of bacteria Allow the bacteria to survive environmental conditions that are not suitable for growth. Highly Resistant to heat, radiation, acids, many chemicals (like disinfectants) because of protein coat!! Resistance due to keratinous outer covering. HEAT MUST BE APPLIED IN ORDER TO STAIN. .entire margin - ANSWER-even smooth all around .Environmentally acquired microbes - ANSWER-p. aeruginosa and b. cepacia .Eosin Methylene Blue-Contains bile salts and two pH indicator dyes which form a dark purple precipitate at low pH - ANSWER-EMB .Esalentin reacts with ferric citrate in the media and turns dark brown/ black. - ANSWER-Positive for Bile Esculin .Extreme halophiles - ANSWER-15-25% NaCl .extreme thermophiles - ANSWER-grow between 65-110 opt above 80 .facultative thermophiles - ANSWER-can grow below 40 .False - ANSWER-Old cultures can lead to _____ Gram (-) results .Fastidious - ANSWER-only grows in a fortified culture media under specific conditions. The more _____________ the organism, the more specific ingredients a medium must have. Uses defined media. .Fastidious (requires enriched media) - ANSWER-Nutrition for Streptococci? .Fermentation products are acidic, lowering pH. The added reagent, methyl red indicator, IMMEDIATELY TURNS RED below pH = 4.4 - ANSWER-Methyl Red (+) test results? .Fermentative organisms - ANSWER-Chemoautotrophs .Filiform Growth - ANSWER-Agar slant. Colony exhibits a dense/opaque surface with a defined edge. .Five I's - ANSWER-inoculation, incubation, isolation, inspection, identification .flat elevation - ANSWER- .Flocculence - ANSWER-Clumpy colonial aggregates seen in broth media. streptococcus .Fluid Thioglycollate Medium (FTM) - ANSWER-Media testing the oxygen requirements of an organism. Contains casein, sodium thioglycollate, and L-cystine. .Friable Growth - ANSWER-Agar slants. Colony exhibits crusty, irregular edges. .Germicidal effect depends on - ANSWER-exposure time, hindrance by any surface, endospores .Good Sewage indicators - ANSWER-E. Coli and S. faecalis .Gram negative cells - ANSWER-have a thinner peptidoglycan layer and have a LPS which is porous so it doesn't retain the primary purple stain. .Gram positive cells - ANSWER-have thicker peptidoglycan layer and stain purple when the teichoic acid crosslinks to trap the stain. .Gram Stain acronym - ANSWER-Can I apply stain .Grape-like clusters - ANSWER-Morphology of Staphlococci