Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Microbiology-Quiz1
| Question | Answer |
|---|---|
| What kind of bacteria has metachromatic granules in its cytoplasm (polymerized phosphate)? | Diptheria |
| Key difference between cytoplasmic and outer membrane of gram negative bacteria? | cytoplasmic membrane has selective transport proteins while outer membrane has porins that allow molecules to diffuse through. |
| Name the bacteria that does not have a cell wall. | Mycoplasma |
| What acid is unique to the cell wall of gram positive organisms? | Teichoic acid. |
| What kind of antigen does flagella have? | H antigen |
| What kind of antigen does LPS have? | O antigen |
| What is located in the periplasmic space of gram negative bacteria? | betalactimases-can degrade penicillins. |
| Why do gram positives stain purple? | higher peptidoglycan (mix of NAG and muramic acid) content in cell wall. |
| Name two bacteria types that make spores | clostridia and bacillus, both large gram positive rods. |
| What component of the spore coat is the source of resistance for the spore? | dipicolinic acid, proteinaceous outer coat. |
| 4 mechanisms of membrane transport-which one modifies the substrate? | passive, facilitated, active and sugar transports. Only sugar modifies the substrate. |
| 2 differences between bacterial and eukaryotic flagella? | In bacteria the flagella has no longitudinal fibers and no membrane coat. |
| 4 functions of cytoplasmic membrane | 1) oxidative enzymes 2)has enzymes for external cell wall synthesis. 3) pump nutrients from dilute external media 4) secrete toxins. |
| Why won't vancomycin work against gram negative bacteria? | Too large, can't cross the outer cell membrane. |
| Where is lipid A of endotoxin located? | embedded in the lipid bilayer of the outer membrane. |
| What are common encapsulated bacteria? (6) | 1) Haemophilus influenzae 2) Streptococcus pneumoniae 3) Bacteroides 4) Strep A 5) Bacillus anthrax 6) Yersinia |
| What is a glycocalyx and what kind of bacteria produce this? | Glycocalyx is a slime layer (carbohydrate polymers on surface of cell wall). made by gram positive bacteria only. |
| What is happening in the lag phase of bacterial growth? | adaptation to host-metabolic activity with no increase in numbers |
| Why are stationary phase bacteria often more resistant to antimicrobials? | Penicillins won't work if bacteria isn't growing/dividing. |
| Give two exceptions to the rule that pathogenic bacteria like to grow at 37 degrees? | 1) mycobacterium leprae-likes to grow on extremities-slightly lower than body temps. 2) listeria monocytogenes-likes to grow at refrigerator temps. |
| What is the best way to count viable #'s of cells? | Culture and look for Colony Forming Units. Plate Count divided by dilution factor. |
| two things bacteria make to get iron from host. | 1)siderophores 2) hemolysins |
| What kind of phosphorylations happen in glycolysis vs. fermentation? | glycolysis includes substrate level and oxidative phosphorylation as part of the ETC. Fermentation only includes substrate level. |
| Give examples of obligate anerobes, aerotolerant anerobes, microaerophiles, facultative anerobes and obligate aerobes | 1) ob. anaerobes: b. fragilis, clostridium perfringes. 2) aerotolerant anearobes: strep, lactobacillus, some clostridia. 3) microaerophiles: campylobacter. 4) fac. anaerobes: e.coli, salmonella, staph. 5) obligate aerobes: nocardia, pseudomonas, TB |
| Name 2 bacteria that can grow on lactose and 2 that can't. | 2 can: e.coli/klebsiella. (have galactosidase) 2 can't: salmonella and shigella. |
| In glycolysis is glucose oxidized or reduced to become pyruvate? | oxidized (and NAD is reduced to become NADH) |
| What process makes carbs from fats? | glycoxylate shunt (bacteria can do, humans cannot). |
| Where does oxidative phosphorylation happen in the bacteria? | cytoplasmic membrane |
| In fermentation is pyruvate oxidized or reduced? | reduced (and NADH is oxidized to NAD). |
| Name first three of 6 different types of fermentation products. | 1) homolactic fermentation-lactic acid (lactobacillus, streptococus) 2) butyric acid fermentation-clostridia. protects from e.coli. 3) propionic acid fermentation (corynebacteria) Used in swiss cheese making. Also bacteria in acne. |
| Name last 3 of 6 different types of fermentation products | 4)Mixed acid: enterobac. (e.coli, salmonella, shigella). Make acetyl COA, formic acid. Salmonella-H2 gas Shigella none. 5) Butanediol formation-acetoin made. non-fecal bacteria: Klebsiella, Enterobacter. 6) Ethanol fermentation-yeasts,C02 as well. |
| what is the role of superoxide dismutase vs. catalase? | superoxide dismutase breaks down superoxide to hydrogen peroxide and oxygen. Catalase breaks down hydrogen peroxide to water and oxygen gas. (anerobes lack both enzymes). |
| What is the strickland reaction? | special fermentation in clostridia, ferment amino acids. |
| Describe body reaction to LPS | macrophages get activated, secrete TNF-alpha. Lead to increase of plasma proteins in tissue, increased permeability of blood vessels, lymphocyte/phagocyte migration and platelet adhesion. Leads to blood vessel occlusion. Systemic-hypotension and DIC. |
| Does endotoxin get destroyed in autoclaves? | No--heat stable. |
| Name 3 endogenous pyrogens. | IL-1, TNF-alpha, IL-6. Lead to release of prostaglandins, increase metabolic rate, vasoconstriction. Fever. |
| What is the difference between functional and actual hypovolemia? | functional: space due to vasodilation. Actual: space due to blood leaking. |
| what pathway of complement does LPS activate? | alternative. (also lectin) Note also activates the coagulation cascade. |
| What is the limulus test? | tests for LPS-horseshoe crab agglutination test. |
| What is the toxic portion of LPS? the antigenic portion? | toxic=Lipid A (conserved, PAMP) antigenic=O-antigen. (antibodies to O used to serotype strains). |
| What is special about Sabouraud's agar that helps Fungi grow? | high acid environment--fungi are acid tolerant |
| what are the two forms of growth for fungi and how do you describe the growth? | 1) yeast-polarized growth and then isotropic growth. 2) hyphae-always polarized from tip-penetrative. |
| What are the 3 phyla that include pathogenic fungi? | 1) ascomyctes-includes candida, aspergillus 2) basidiomycetes-mushrooms, cryptococcus neoformans. 3) zygomycetes-including mucor. |
| name of sterol in fungi cytoplasmic membrane? | ergosterol (amphotericin B binds to while the enzyme that makes it is the target for azoles) |
| What is the major component of the fungus cell wall? | beta 1,3 glucan inner layer (PAMP) and chitin--crosslinked via glycosidic bonds. GPI anchors transfer carboyhdrates to beta 1, 6 glucans)-cross link with glycoproteins that protect the inner glucan layer. (MANNAN PROTEINS=outer layer) |
| Are fungi motile? | no |
| Which fungus does not use ergosterol in its cytoplasmic membrane? | Pneumocystis |
| the antibody response of a host to fungus is directed at what? | the carbohydrate portion of glycoproteins (mannan, glactomannan, xylose) |
| what is the only pathogenic fungus with a capsule? | cryptococcus neoformans. Capsule is made of polymers of glucuronoxylomannan (GXM). |
| how is the geographic distribution of fungi determined? | delayed type hypersensitivity skin testing |
| What is the difference between exogenous and endogenous fungi? | exogenous=free living, ecological niche is in nature. endogenous=associated with human hosts, don't survive very long outside (candida albicans). |
| name 2 examples of secondary metabolites of fungi. | 1) lovastatin-made by aspergillus terreus. 2) aflatoxins-toxic at low concentrations-concern in grain industry. (also with peanuts). |
| What are two terms for hypha that don't have septa? | 1) aseptate 2) coenocytic-mass of protoplasm from repeated nuclear division, no cell fission. |
| In C. albicans what dimorphic form is found in the host vs the environment? | host=hyphal, environment=yeast. (unique, other dimorphic fungi are opposite). |
| What is auxotrophy? | inability to synthesize essential metabolites. (wild type is prototroph). |
| What experiment showed that mutations are spontaneous and not induced by selective pressure? | Lederberg-replica plating with velvet (selective and non-selective media). Can show colony had resistance before put on the selective media. |
| what test helps with ordering genes in a pathway? | Cross-feeding analysis. If precurser feeds a neighbor it means the precurser is at the end of the pathway. |
| What is a good way to enrich your media for auxotrophs? | penicillin enrichment on minimal media. Get rid of any colonies that can grow, leaves behind those that can't (auxotrophs). |
| What is a good way to get lethal mutations to examine? | Get temperature sensitive mutations-silent at low temps, denature protein at high temps. |
| how do you determine the number of genes in a biosynthetic pathway? | genetic complementation test-chromosome and plamsid. If mutation in same gene then get no product, if in different genes, then they complement each other and can get product. |
| How do you study commensals that can't be cultured? | look at small subunit RNA. (highly conserved) |
| What are the two types of bacteriaphage? | 1) Lytic 2) Lysogenic-eg. Lambda, see site specific recombination to form prophage-viral DNA in bacterial DNA. C1 repressor stops viral DNA genes from being repressed until times of DNA damage/stress and then they are expressed and go into lytic cycle. |
| What is a way bacteria protect themselves from phage? | restriction enzymes |
| What kind of recombination do transposons do? | illegitimate recombination-nonhomologous. Use insertion sequences to insert at random locations. Transposons are often involved in antibiotic resistance. |
| Name 3 mechanisms of gene transfer in bacteria | 1) transformation-bacteria get DNA from environment. 2) Transduction-viral transmission from phage. Can be generalized-random insertion, or specialized if lambda always inserts in same place). 3) Conjugation-bacterial sex (F pilus). |
| 3 examples of bacterial toxins that are transfered by phage? | 1) e.coli shiga like toxin. 2) diptheria toxin. 3) cholera toxin. |
| What is an episome? | extrachromasomal DNA element that is capable of autonomous DNA replication but can also integrate into the chromosome. F is an example. |
| how does the rapid chromogenic antibiotic resistance test work? | if bacteria is resistant will see color as nitrocefin is cleaved when beta lactamase is made (degrades beta lactam antibiotics) |
| How does sulfonilamide work? | Anti-metabolite (anti folic acid metabolism-needed for DNA synthesis), used for urinary tract infection-broad spectrum. Bacteria static. |
| Name 4 antimetabolite antibiotics. | 1) sulfonilamide. 2) trimethoprim-stops Dihydrofolate reductase. 3) bactrim-combo of 1/2. 4) isoniazid-affect mycolic acid-imp. for TB. cidal. |
| Which penicillins are sensitive to acid? | Pencillin G (also sensitve to beta lactamase). Ineffective for gram negative enterics. Pen V. is acid resistant. |
| Which penicillins are broad spectrum? | ampicillin/amoxicillin. Get high serum levels with amoxicillin. |
| Which penicllins are best for enterics/pseudomonas? | tricarcillin, piperacillin. (less good for gram positives) |
| which penicillins are best for staph (narrow spectrum) | oxacillin, dicloxacillin, nafcillin, methicillin. Why are these best? Becuase they are resistant to penicillinase. (unlike penicillin G/V or ampicillin groups). |
| What bacteriocidal antibiotic class is similar to penicillin but with less allergic properties? | Cephalosporins. 3 generations. 3rd generation can handle pseduomonas better at cerebrospinal fluid penetration, others can't. |
| What kind of beta-lactam antibiotic is good for aerobes but not anerobes? | monobactams-azetreonam. Also not good for gram positive. |
| What is augmentin? | beta lactam with a beta lactamase inhibitor (clavulonic acid with amoxicilin). |
| How does vancomycin work? | inhibits gram positive bacteria only- (too big to fit through the porins). R-D-ALA-D-ALA cross link binding-inhibit glycopeptides. |
| Name 2 examples of drugs that affect membrane permeability (and thus bacterial energy source-cidal). | 1) polymyxin B and E-only topical. Gram negatives. 2) Daptomycin (cubicin)-gram positives only. |
| 3 examples of aminoglycosides and how they work. | 1) steptomycin 2) amicacin 3) gentamicin. Work by interacting with small 30S ribosomal subunit--inhibit translation. Cidal-lead to bad proteins. |
| Why do we see so much drug resistance for aminoglycosides? | Very specific binding to the 30S ribosome. (gentamicin has many binding sites and works much better). |
| How do tetracyclines work? | tetracycline and doxycycine block tRNA and are bacteriastatic. Diable ability to synthesize more proteins. Great for intracellular parasites. Chlamydia, rickettsia. Bad for pregnant and kids teeth. |
| How do macrolides work? 2 examples. | 1) azithromycin 2) erythromycin. Both block chain elongation-50S subunit. |
| Which antibiotic is particularly good for anerobes? | Clindamycin |
| What is a limitation of the Kirby-Bauer Disc Diffusion? | Can't be used for determination of Minimal bacteriacidal concentration. (good for multiple testing of antibiotics). |
| What are carbapanems (imipenem)? | antibiotic with beat-lactam ring, broad antimicrobial spectrum, restant to most lactamases, susceptible to renal dipeptidase so use with cilastatin. (Primaxin). |
| Name 2 B-lactamase inhibitors | 1) Clavulonic acid 2) Sulbactam |
| Name 3 glycopeptides and their coverage | 1) vancomycin-Gram positive 2) cycloserine-TB drug 3) Bacitracin-Gram positive Good for topical therapy only. Too toxic for systemic. |
| What 2 conditions inhibit streptomycin? | 1) acidic 2) anaerobic *note that aminoglycosides like streptomycin/genotmycin should only be used in patients with immune compromise as they can damage 8th cranial nerve/renal function. |
| Name 5 antibiotics that inhibit 50S ribosomal function. (all static). | 1) erythromycin-static-chain elongation 2) azithromycin-static-chain elongation 3) Chloramphenicol-static-chain elongation-can get anemia. Good for bacteroides. 4) Clindamycin-good for anaerobes. 5) Streptogramins. |
| How do oxazolidinones (linezolid) work? | inhibit translation-block tRNA translocation-interact with 16S and 23S rRNA. Great for gram positives. |
| How does mupirocin work? | bind to tRNA synthetase and results in no charged Ile-tRNAs. Static at low concentrations, good for MRSA. |
| What 3 drugs are good for inhibiting DNA replication? (one is particularly good for anaerobes) | 1 and 2 are both quinolones-ciprofloxacin and moxifloxacin. Broad range. Inhibit DNA gyrase. Bad for pregnant and children-hurt growing bone. 3) metronidazole-need anaerobic conditions. Binds to DNA and fragments it. 3) |
| what antibiotic inhibits RNA synthesis? | Rifampin-broad spectrum |
| Example of antibiotic antagonism? | agent needing growth (penicillin) and bacteria static drug (tetracyline) |
| Example of antibiotic syndergism? | agent damging cell wall (polymxin or penicillin) and agent that is taken up poorly (aminoglycoside). |
| 5 important anti-fungal drugs: | 1) amphotericin B-bind to sterol 2) Nystatin-bind to sterol, can't be used systemically--too toxic. Static. 3) Fluconazole/ketoconazole-inhibit membrane synthesis. 4) Caspofungin-inhibit glucan synth. cidal. 5) Flucytosine-antimetabolite. replace urac |
| How is fungal resistance conferred? | changes within the fungal genome itself. No resistance mechanisms have been discovered so far. (do see efflux pumps like bacteria have). |
Created by:
act99
Popular Science sets