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Microbio LAB FINAL
| Question | Answer |
|---|---|
| what does ubiquitous mean? | Existing or being everywhere at the same time |
| why can we see a colony of cells but not a single cell? | A colony of cells is comprised of MANY cells that divided and reproduced from a single one |
| is it more effective to estimate by size of colonies or number and why? | number, size would just be a parent cell that divided into a single cell, the total colony count are original cells that divided |
| bacteria on skin, good or bad? | bacteria are part of our microbiome (not the pathogens, of course) |
| mold on skin, good or bad? | mold is a fungus, not meant to be on our skin, athlete's foot |
| ways to control microbial levels on skin, surfaces, air | wash hands, lysol wipes, masks! |
| 2 reasons we heat fix | kill organisms, fix organisms to slide |
| possible outcomes to overheating a slide | burn samples, crack slide |
| 2 reasons we use only a small amount of bacteria | cells clumps can trap stain making it hard to see gram stain, also difficult to make out general morphology! |
| why do we simple stain and how does it work? | cell shape+arrangement, heat fix, + dye added to attract to the - charge in DNA/RNA |
| why do we negative stain and how does it work? dye used? steps? | dyes background of slide, see capsule of bacteria with GLYCOCALYX outer layer, - dye added to REPEL - charge in DNA/RNA; nigrosin; angle another slide on drop of nigrosin, slide across (like a blood slide) |
| magnification vs resolution | Magnification = making an object appear larger, Resolution = being able to distinguish between two objects |
| scanning lens, low power lens, high dry lens, oil immersion lens magnification | 4x, 10x, 40x, 100x (SLHO Specimen Lie Horizontal to Occular) |
| magnification of ocular lens | 10x |
| 2 reasons we being with scanning lens | center specimen, prevent slide from cracking since it's shortest |
| why is oil used with immersion lens? | oil has the same refeactive index as glass, allows light to focus onto specimen |
| why isn't oil used with other lenses? | the other tubes are wider and don't need light to be as focused |
| what is a colony? how do they form? | colonies are bacterial growth collections, arose from single cell |
| why should we sample a single colony? | single colony comes from single cell, so isolates a pure strain |
| plate label should be on which side? | agar side, agar placed face down in incubator |
| 3 pieces of info. to label plate | date, name, organism name |
| 3 purposes to aseptic technique | prevent you from getting contaminated, prevent others, prevent plate from getting contaminated |
| why do we want to identify acid-fast bacteria? | gram-staining doesn't work, they're pathogenic like tuberculosis |
| what are acid-fast bacteria? what stains used? steps? | bacteria with a mycolic acid cell wall; carbol fuchsin; carbol fuchsin, WATER, alcohol, WATER, methlyene blue counterstain |
| 2 genera of acid-fast bacteria | mycobacteria, nocardia |
| acid-fast protist eukaryote | cyrpytosporidium |
| simple stain vs differential stain | simple stain - 1 dye, differential stain - multiple dyes |
| examples of differential stains | gram stain, acid fast |
| what does gram staining tell us? | cell wall type of bacteira, gram positive (purple) have a thick peptidoglycan cell wall, gram negative (pink) have thin peptidoglycan + LPS outer membrane |
| steps of gram staining | crystal violet, WATER, iodine, WATER, alcohol rinse, WATER, safranin counterstain, WATER, blot with lens paper |
| salmonella is gram negative, when stained with crystal violet what color would it be? what color would it be when finished | this is first step, so purple; red/pink when done! |
| if decolorizer was left on too long what would happen? | alcohol would poke holes in ALL cell membranes, they'd lose purple dye |
| what would happen if slide was not heat-fixed prior to staining | the microorganisms might fall offn during water rinses, AND they wouldn't be killed |
| what bacteria do Entero-Pluri tests identify and why do we care about them? | Enterobacteriaceae and many are pathogenic, so needed to treat them |
| what's a coliform? | Enterobacteriaceae that ferments lactose, producing acid AND gases, like E. coli |
| if many coliforms aren't pathogenic why do we test for them in water | they are found in mammal intestines so presence in water means fecal contamination, and pathogens could be present in this water bc of it |
| what causes Entero-Pluri Test color changes? | metaboism which causes pH changes, and therefore, color changes |
| benefits of a multi-test system | more efficient, less time consuming, uses several biochemical tests at once |
| how does UV light kill cells? | UV light creates thymine dimers in DNA, affectings transcription, translation, leading to mutations and death (thymine bonds together) |
| purpose of hospital OR UV light bulbs when rooms is not in use | long exposure of UV to bacterial DNA creates thymine dimers, killing them |
| common mistakes in gram staining: 1) dont see anything 2) everything is purple 3) everything is pink | 1) didn't heat fix properly, bacteria washed off 2) didn't decolorize enough 3) decolorized too much |
| what does krebs cycle convert into what and | can't use pyruvic acid so it's broken into acetyl-CoA to build: NAD, FADH2 and provide electrons for electron transport chain |
| where does electron transport take place? | periplasmic space between outer and inner membrane |
| what makes ATP and can it work in reverse? | ATP synthase, driven by the protons trying to get back into the cells because of the gradient; yes! ATP can be used to pump protons back into cell membrane |
| what are carbohydrates composed of? | they're a sugar with a 1 carbon, 2 hydrogen, 1 oxygen ratio (CHO, 1:2:1) |
| what is glycolysis and what process is it used in? | converting glucose to pyruvic acid, used in fermentation and respiration |
| what's gluconeogenesis? | building glucose from pyruvic acid |
| optimal number of colonies | 25-300 |
| 4 bacterial growth phases | lag, log, stationary, death |
| lag phase | no increase in population but increased activity |
| log phase | logarithmic/exponential growth in population |
| stationary phase | equilibrium, deaths equal production of new cells |
| death phase | population decreases at a logarithmic rate |
| what's oxidative phosphorylation? | NADH and FADH2 build a protein gradient in electron transport chain |
| what's fermentation? | anaerobic, so 1 glucose makes 2 ATP, the energy remains in the products like lactic acid instead of being readily available |
| ATP # in eukaryotes vs prokaryotes | 38 in prokaryotes, 36 in eukaryotes per glucose molecule (38P, for power) |
| what does phosphorylation mean? | adding a phosphate to a molecule |
| what's thermal death point? | lowest temp it takes to kill all in 10 minutes (lowest POINT in 10 minutes) |
| what's thermal death time? | minimum time to kill all in liquid at specific temp? (time at temp) |
| what's decimal reduction time? | how long it takes to kill 90% at a given time |
| moist + dry heat examples | autoclave, flaming |
| what's pasteurization? | sanitizing through high temp short time (HTST) or through UHT (ultra high temp) |
| what's snap-freezing? | add them to glycol that's pre-chilled to preserve, slowly freezing and thawing KILLS |
| what's ionizing radiation? | x-rays to form oxygen radicals to damage DNA |
| what's non-ionizing radiation? | UV light, thymine dimers |
| what's dessication? | removing liquids, drying them out, some may form spores |
| how to affect osmotic pressure? | add salt or sugar to pull water, so cytoplasm from cell wall affecting cell division and metabolism |
| what does sterile mean? | fully kills everything |
| what's a disinfectant? | destroy harmful microorganisms on non-living surfaces |
| what's an antiseptic? | destroy harmful microorganisms on living tissue |
| what's a sanitizer? | lower microbial count to safe levels, may use disinfectants |
| bacteriocidal vs bacteriostatic | kills bacteria; prevents growth, like snap freezing |
| sepsis meaning | pathogens in blood or tissue |
| aseptic meaning | lack of infection |
| antiseptic meaning | things that fight off infection |
| factors in antimicrobial treatment | time of exposure, characteristics (like gram +, -), number of microbes, environmental factors (biofilms) |
| how does lac operon work | lactose binds to repressor, allowing lactose transcription to occur! |
| how does trp operon work | if too much, tryptophan binds, activating a repressor, turning it off |
| direct measures of colony counting examples | count colonies, filter on graph plate or slide |
| indirect measures of colony counting examples | measure metabolic activity, observe turbidity (cloudiness) |
| what's transduction? | transfer of DNA from a donor to a recipient cell by a bacteriophage |
| what's transformation? | transfer of DNA from a donor to a recipient as naked DNA in solution |
| what are transposons? | "jumping genes" DNA sequences that can move locations within a genome |
| what's selective media? | inhibit some organisms, allow the growth of others |
| what's differential media? | distinguish ebtween microorganisms, changes in color |
| what's defined media? | specific chemicals at known concentrations; will say something like 1.5 g/liter of NaNO_3 |
| what's complex media? | beef, yeast extracts |
| are gram positive or negative bacterial cells more affected by antibiotics? | gram positive cells, because antibiotics target the peptidoglycan layer |
| 4 bacterial flagella arrangements | monotrichous + polar, ampitrichous + polar (ambidextrous), lophotrichous + polar, peritrichous |
| cryophiles are found where? | ocean depths, polar regions |
| psycotrophs are found where? | refrigerators |
| mesophiles are found where? | human body, usually pathogens, common in spoilage and disease organisms |
| thermophiles are found where? | hot springs, compost piles, endospores are examples of organisms that can live in this temp |
| hyperthermophiles are found where? | volcanic hot springs, deep sea hydrothermal vents |
| what are obligate aerobes and where in tube are they found? | ABSOLUTELY need oxygen, surface of agar where more O2 is present |
| what are obligate anaerobes and where in tube are they found? | CAN'T use oxygen, cluster at bottom |
| what are facultative anaerobes and where in tube are they found? | can use oxygen, so found throughout tube, but clustered more at top, since O2 creates most ATP |
| what are aerotolerant anaerobes, and where in a tube are they? | can survive where there's O2, but can't use it :/ they're just all over the tube, not anywhere specific |
| what are microaerophiles, and where in a tube are they? | middle, where it's not too much not too little O2 |
| chemical requirements to grow bacteria | CHNOPS, carbon, hydrogen, nitrogen, oxygen, phosphorous, sulfur and trace elements and growth factors |
| what is the nucleoid? | circular part of prokaryote/bacteria that contains DNA |
| bacterial shapes | cocci (circle), bacilli (rod), spirochete (spiral), vibrio (coma-shape) |
| bacterial arrangements | diplo (pairs), strep (chains), staph (clusters) |
| what's a cofactor in an enzyme? | non-protein organic molecule, electron carrier or metal that is the helper molecule portion of an enzyme |
| what's an apoenzyme? | protein part of an enzyme (a protein) |
| what's a holoenzyme? | cofactor + apoenzyme, the whole enzyme (hologram of the full thing) |
| is the active site on an enzyme specific or general? | SPECIFIC to the substrate binding to the enzyme |
Created by:
AKDakd