Micro lab final Flashcards

Terms Definitions
lime quarry
require O2
gram- positive color
parts of microscope
propionobacterium acnes
responsible for acne
uniform fine turbidity
uniformed cloudiness
sterilization autoclave
121C 15psi 15min
point mutations
single base pair changes
plasmodium falciparum
the most severe protozoan
Immersion oil constrains __________ (light-scatter)
heat fixing
attaches cells to slide
Using textbook, create case history that would suggest a Klebsiella pneumoniae infection
blood agar
distinctly seperates and identifies Streptococcus and Staphylococcus strains
many molds secrete, together with hydrolytic enzymes, inhibit the growth of competing microorganisms.
ability/inability to grow the presence of oxygen
antimicrobials that are suitable for nonliving surfaces
Crystal violet is a _______ dye.
endoposre stain chemicals
malachite green and safranin
Study of yeast, mold and mushrooms
agar slant
liquid agar hardened at slanted position
Mycobacterium tuberculosis
a bacteria which uses mycolic acids
pure culture
contains only one kind of bacteria
gram- positive (pink)
lipoprotein and lipopolysaccharide are found in conjunction with a thin peptidoglycan layer
lenses are adjusted so that the specimen remains almost in focus after the microscope is rotated the nosepiece to utilize a different objective lens
eukaryotic cells
mostly larger than prokaryotic cells and usually contain a visible, membrane-bound nucleus
movement of motile organisms that are positive or negative (e.g. chemotaxis, phototaxis, aerotaxis)
Acid fast stains are primarily used to ID ____________ species.
the best limit of resolution is
.2 micrometers
MAC, Mannitol Salt and BAP are examples of what type of media?
enrichment media
contains some component that permits the growth of some species
capsule stain
nigrosin, negativly charged and stains background. crystal violet stains the cell.
Describe the symptoms of Giardia infection. How is it contracted in an urban setting?
DiarrheaContracted by ingestion.Drinking water contaminated with feces
bacteriostatic agents
inhibit microbial growth but do not kill the microbe (usually requires immune system)
simple stain
prepare by coloring the bacteria with a single, basic dye.
The ________ _________ method is the most important isolation tool.
Streak Plate
Lab 17Define antiserum.
The known preparation of antibodies used in direct serological testing.
Selenite Broth and Tryptic Soy Broth are examples of what type of media?
enrichment broth
characteristics of eukaryotes.
have nucleus. have internal membrane-bound organelles. have larger ribosomes. use mitosis and meiosis. have more than one chromosome. larger cell.
Obligate intracellular parasite (OIP)
Enters host cells by phagocytosisMust grow and reproduce in host cell
missense mutation
mutations which cause a change in the amino acid sequence ( AAA-AAC changes the amino acid from lysine to asparagine)
serial dilution
used to reduce the cell density to achieve countable plates
triple sugar iron agar
differential agar in which bacteria that form hydrogen sulfide will blacken the agar
Lab 20Define the following terms: disinfection, disinfectant, antiseptic.
Disinfection: reduction or elimination of pathogenic microbes or materials. Disifectant: chemicals used to disinfect inanimate objects. Antiseptic: nontoxic disinfectant suitable for animal tissue.
What is Catalase +, but Coagulase and mannitol -?
Staph epi
found in soil in water. energy from chemicals (heterotrophs). size 10 micrometers- 5mm. few cause disasae. ex: amoebas, paramecia
What 3 morphological types of capsids did you observe in the demonstration material?
1. Helical2. Polyhedral3. Complex
casein protein may be digested
coagulating milk to form a curd
lauryl tryptose broth
media used in the presumptive test for the presence of coliforms. lactose containing medium. bacteria, if aerogenic (gas produce) in this broth, are presumed coliforms.
What two bacteria were not inhibited on the MacConkey agar and produced acid thru fermentation?
Escherichia coli andEnterobacter aerogenes
Lab 19State whether hypertonicity has a static or a cidal effect on microorganisms.
Has a static effect. (Plasmolysis)
4 stains used in Gram staining
Crystal Violet, Gram's Iodine, Acetone Alcohol, Safranin
techniques to determine motility
wet mount, hanging drop and semi-solid media
spechtrophotometers have what issues?
since dead cells refract as well, it is difficult to see the death phase and occasionally one will not appear at all, machines can be finicky, physics get in way, (limits to linear lines vs concentration)
Eosin Methylene Blue Agar
media used for the isolation of fecal coliforms--> selective and differential, for gram negative
On the Hektoen agar, S. typhi was:
Blue-green with a black ppt
Lab 20Name two chemical agents which are reliable for sterilization.
Ethylene oxide gas and aldehyde.
Methylene blue strip
blue in presence of O2. clear in abscence of O2
On the Hektoen agar, E. coli was:
A blue-green growth without black ppt.
Lab 18State the significance of heterophile antibodies in serological testing.
During infections caused by EBV the body produces nonspecific heterophile antibodies. These antibodies can be detected because of a cross reaction with horse or sheep blood (serving as known antigen) that causes the red blood cells to clot.
Describe the symptoms of Rocky Mt. spotted fever?
Fever, headache, and a rash that includes palms of hands and soles of feet as well as rest of body.
function of the methylene blue in acid fast?
It stains the acid fast negative cells
Lab 19Describe osmosis in terms of water flow through a semipermeable membrane.
Osmosis is simple defustion of water through a membrane from areas of higher water concertration to lower water concentration.
Procedure for a negative stain
1. drop of nigrosin dye
2. mix in a loopful of broth culture
3. draw a second slide across the surface
4. push the dye and cells across the slide
5. let the smear air dry
What does an inhibition from Phenol Ethanol tell you about the bateria that is inhibited?
It is probably a Gram neg. bacteria (like Enterococcus faecalis)
What info is recorded on day 2 of record keeping?
what plates showed growth, colony morphology, presumptive id (w/ hemolysis), and set up confirmatories and sensitivity testing
Lab 18State what disease the RPR and the FTA-ABS procedures test for. Indicate which of these is a presumptive test, which is a confirming test, and why.
RPR: tests for syphilus. It is a presumptive test because it detects antibodies made against the body's own lipids (nontreponemal) that may be present during other diseases, as well. FTA-ABS: tests for syphilus. Is a confirming tests because it test for antibodies made specifically against the syphilus-causing spirochete Treponema Pallidum(treponemal).
salt water
stains add...
gram- negative color
semisolid media
0.1-1.% agar
xylose fermentation
yellow (non pathogens)
mucoid, moist or dry
septate hyphae
all members of aspergillus
Staphylococcus colonies appear
large and opaque
streak plate
uses the quadrant method
Sodium thioglycolate binds ________, thus preventing its use by microbes.
ability to distingish two objects
Which of the bacterial respiratory pathogens can you be immunized against?
total coliform
entire coliform population, lactose fermentors
bacteriocidal agent
kills bacteria provided concentration is high enough
a bacterium which possesses a different genetic make up (genotype) This may or may not result in physical change of bacteria (phenotype)
organisms that sink to the bottom
Micrococcus luteus
gram-positive cocci (round). Anaerobe. Colonies are canary yellow. Tetrade. Rod-like.
What does an autoclave NOT kill?
would bacteria be likely pathogenic at 37 degrees?
live in pH 10 or greater
media for skin
EMB, TSI slant, CTA slants
alpha hemolysis
partial breakdown of blood cells. green tinge to develop around the colonies.
dehydrated media
standardized media prepared in large batches, desiccated, bottled, and sold. *all bacteria must have water, carbon, an energy source, nitrogen, and minerals
The ______ stain is the most important stain in microbiology.
pigment description
color, opaque, translucent, shiny or dull
What is Catalase, Coagulase, and Mannitol +?
Staph aureus
Ability to change power with minimal focus adjustment
live in pH of less than 5
Design a case study that would suggest a Histoplasma infection
beta hemolysis
full lysis of blood cells, causing clear zone to appear around colony
Stationary phase
cells are at max growth potential, limited by nutrient concentration being too low, metabolic products which inhibit cell, space limitations (densely packed) . cell numbers remain same but not a static phase. cells are continuously growing up to a point and then stopping, population keeps moving
differential media
media in which biochemical products of some chemicals react with, creating a visible result in the colony or media
Which three bacteria were streaked onto the darker red desoxycholate agar?
Escherichia coliStaphylococcus aureusSalmonella typhimurium
Which bacteria was inhibited by the high salt concentration in the Mannitol Salt Agar?
Escherichia coli
Normal flora of skin
Staph epidermidis, staph. aureus, diptheroids
What shows a positive reaction to a Catalase test, Staph or Strep?
types of microorganisms
virus, algae, fungi, protozoa and bacteria
What is sputum specimen
mucus coughed up from respiratory tract
selective pressure
can cause a mutant bacteria to gain dominance over its wild type
microscopic field
the area of the microscope slide that you see through a lens
Which bacteria was found to be not inhibited by desoxycholate and fermented lactose to acid?
Escherichia coli
Lab 19Define pasteurization.
Mild heating of materials to kill particular spoilage or pathogenistic organisms.
Positive result for Coagulase test?
clumping seen in 5-20 seconds
Bacteria morphologies
Bacilus: rod. Cocci: round. Helical: spiral
Cite some precautions in patient care to prevent nosocial Staphylococcus aureus
Preventative-(nose and skin)Tissue when sneezeWash hands
Why is it important to autoclave thioglycollate media before innoculating it with bacteria like Clostridium sporogenes?
remove oxygen from media
mixed culture
by using what kind of culture will you end up with two complete separate cultures?
Which bacteria appeared yellow on the XLD agar and what does this indicate?
Enterobacter aerogenes,Produces acid from xylose fermentation.
Lab 18Define titer.
Indicates how much it is possible to dilute a patients serum and still have detectable amounts of antibody in the serum (the amount of a certain antibody in the serum). The more antibodies present the more it is possible to dilute the serum and still ditect the antibodies.
microscope- what holds the slide?
what secures the slide on the stage?
what holds the ocular lenses?
what holds the head and stage?
the stage
the slide holder
the head
the arm
FTM tube
more oxygen at top. No oxygen at bottom
chemically defined or synthetic media
composed of known amounts of pure chemicals
a halo of discoloration around organism
what shows that amylase was produced?
Numeric Aperture is the
measure of a len's ability to capture light coming from the specimin and use it to make an image
Lab 20List five factors which may influence the antimicrobial action of disinfectants and antiseptics.
1. concentration of agent2. temperature at which agent is used3. types of microbes present4. number of microbes present5. nature of material carrying the microbes (dirt or other materials might inhibit agents).
Hair, skin, nails sample collection
storage at 4C or room temperature is acceptable
What two bacteria did not grow on the Hektoen agar indicating an inhibition to bile and/or acid fuchion or bromthymol blue dyes?
Staphylococcus aureus andShigella flexneri
Lab 19Describe how ionizing radiation kills microorganisms and state several common applications.
It ionizes water and other molecules to form radicals that can break DNA. Used to sterilize desposable medical supplies like gloves or syringes or to retard spoilage in meats or fruit.
What distinctive feature makes the mycoplasmas unique from other bacteria?
Lack of cell wall, and therefore high pleomorphic (no definitive form).Cell membrane contains sterols.
what is the Ziehl-Neelsen (ZN) method and sequence of steps
Acid fast stain. heat fix emulsion, cover smear w paper towel and carbolfucshin stain, steam for 5 min, remove paper, rinse, decolorize w acid alcohol, rinse w distilled water, counterstian w M. blue 1 min., blot dry
Lab 19State whether low temperature has a static or cidal effect on microorganisms, and indicate why.
It has a static effect on microbes since it inhibits growth but doesn't kill.
sterile body fluids and urine samples
stored at 4C for up to 12 hours ***Blood and CSF must be processed immediately***
2 benefits of making bacterial heat fixed smear?
it makes the bacteria adhere to the slide and it coagulates the protein to make them more visible
How to read test results for Bile Esculin?
+ media turns black, - remains tan
Lab 19State whether moist or dry heat is more effective in controlling microorganisms, and indicate why.
Moist heat is the most effective in killing because of its ability to penetrate cells.
nutrient solutions
eukaryotic microorganisms classified in the kingdom Fungi
confluent growth
colonies flowing together
movements directed towards chemicals
Streptococcus colonies appear
small and translucent
clumping of organisms in broth
Gram's Iodine covalently links crystal violet to a Gram _______ bacteria's cell wall.
Positive result for Catalase test?
Serum assays
cryptococcal and histoplasma antigen tests only
bacterial variation does not always mean a mutation has occured. Occasionally the environment can influence a gene or gene set ro produce a different level of expression (pigment production, motility, sporulation, toxin release, nutritional requirements)
able to construct cellular molecules using preformed organic molecules for carbon and energy
resolving power
ability to distinguish close-together objects, resolution, and clarity
consist of solvent (water/ethanol) and a colored molecule (chromogen)
grows in a variety of shapes
are all members of the Enterobacteriaceae family able to ferment lactose?
Characterize the genus Staphylococcus
G+ cocciIrregular clustersSalt tolerantCatalase +
mutations which add or remove segments of DNA. Results in shifting of reading frame which can change everything down the line.
T or F? spectrophotometer readings are okay for quick estimations, they will not give you a physical number for the bacteria
differential stain
a procedure that distinguishes between various microbes according to their ability to retain certain dyes.
eukaryotes, range in size from single cells to giant sea kelp. contain chloroplasts
reproductive spores formed at the tips of branching filaments
When using oil immersion, only the _____X objective should be used.
capsule production
increases virulence in some microbes, making them less vulnerable to phagocytosis
Any chemical substance produced by a microorganism that inhibits growth of or kills other microorganisms
palladium pellets
catalyst, 2H2 + O2 --> H2O
Compare structures of molds and yeast
Yeasts-unicellular fungi.Reproduce asexually by budding.Sexually by formation of spores
nonsense mutations
mutations which cause a codon to become a stop codon which can cause a shortening of the coded protein
staphylococcus, streptococcus and neisseria are
very common in respiratory tract
macconkey's agar
used for dip-n-count, it is a selective, differentiable medium for gram-negatives
solid media
used for separation of bacteria and letting them grow in isolated colonies or for maintaining stock culture
acid dyes
repelled by bacteria because of the negative charges of the chromophores- these leave the cell colorless and color the background instead. *used in negative staining. *congo red, nigrosin, eosine, and acid fuchsin.
endospore staining
detect the presence and location of spores in bacterial cells. endospores are a dormant form of bacterium that allows it to survive poor environmental conditions due to keratin (through outer covering). located centrally, terminally, or subterminally
Which organism was not inhibited on the MacConkey agar but did not ferment (shown thru colorlessness)?
Proteus hauseri
2 genera of bacteria w endospores
bacillus and clostridium
What is added to bacteria in performing a Catalase test?
Hydrogen Peroxide
respiratory secretions samples
no rush, specimens may be refrigerated if necessary
What are retroviruses?
Change genetic make up of cell. Reverse transcriptase
CTA (cystine trypticase) agar
tests for breakdown of carbssugar fermentation = yellow
starch agar
media used to show how amylase breaks down the starch (using iodine)
capsules are composed of
polypeptides which are difficult to stain
What type of media allows bacteria to be differentiated into groups by biochemical reactions on the medium?
Differential media
brownian motion
not tru motility. motion caused by molecular boombardmant and water currents
What is coagulase?
Enzyme used by S. aureus to induce coagulation
XLD (xylose lysine deoxycholate) agar
selective against normal coliforms (E. coli and gram + bacteria)
water, carbon, an energy source, nitrogen, and minerals
nutritional requirements of bacteria.. all must have what 5 things?
List the primary, mordant, decolorizer and counter stain for Gram Staining:
1. Crystal Violet2. Gram's Iodine3. Acetone Alcohol4. Safranin
what is an endospore
a dormant form of bacterium thatb allows it to survive lean environmental conditions
What type of technique is used for bacteriophage plaque asseys?
Soft Agar overlay
Acid fast stain
1. carbolfuschin (heat) 2. acid-alcohol 3. counter stain methylene blue
What precautions should you take in caring for a patient with ringworm?
Do not touch infected area
if lactose is not fermented
proteins are instead used for energy, the solution will become alkaline and more blue
List the four types of sterilization used in the microlab:
1. Autoclave2. Gamma radiation3. Bunsen burner4. Electric loop/needle sterilizer
Lab 19State two methods of applying dry heat.
Hot air sterilization and incineration.
Gram stain
1. crystal violet 2. iodine 3. ethanol 4. safranin
Describe E. coli's growth on the EMB agar:
Growth was pink and mucoid
Lab 17Define: a) direct serologic testing and b) indirect serologic testing.
a) the use of known antibodies, called antiserum, to identify an unknown antigen.b) unknown antibodies being made against an antigen associated with a particular disease are detected using a known antigen.
Why is heat-fixing important? (4 reasons)
To kill the bacterial cells
To make cells observable
Attach to slide surface
Denature enzymes
List the first 4 cardinal rules of microbio safety:
1. Do not mouth-pipette2. Manipulate infectious fluids carefully3. Restrict usage of needles and syringes4. Use protective lab clothing and safety glasses
Lab 20State why chemical agents are usually unreliable for sterilization.
They don't quickly and reliably kill all viruses, microbes and endospores.
What info is recorded on day 3 of record keeping?
Positive ID and sensitivity results
Can you do a calculation of generation time with turbidity measurements?
no, generation time requires you have a starting and ending CFU/mL.
What info is recorded on day one of record keeping?
Source, what plates streaked, and direct gram smear results.
how is negative stain different from other stains?
The dye is acidic and has a negative charge
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