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micro lab final
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121
Microbiology
Undergraduate 2
04/20/2013

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Term
What is the purpose of doing an API test?
Definition
an identification system to test for enterics
Term
what is bacteriocidal?
Definition
something that kills bacteria
Term
what do you look for while trying to identify a gram positive stain?
Definition
Color differintiation
Term
Whats the gram stain procedure
Definition
heat smear first, flood with crystal violet, iodine, acetone, safarin
Term
what is the purpose of using microbial metabolism or why is it important and what is the procedure?
Definition
pg 74-75, to figure out jf bacteria is positive or negative for all the tests that are ran. Match results of bacteria to organism number in front of the book to see what it correlates with
Term
What are formulas for dilution factor?
Definition
aliquot/ total volume
Term
How do you find concentration?
Definition
stock X TDF, or ____________
Term
what does it mean when a bacteria can metabolize nitrate?
Definition
They are usually anaerobic
Term
What does the IMViC series test for?
Definition
To differintiate between fecal and non fecal orgin
Term
What are the 2 functions of bacterial capsule?
Definition
to keep from sticking to surfaces and to hold water in and to keep from being phagotized
Term
what are the functions of biofilms?
Definition
anti microbial resistance
Term
what does faculatative anerobes mean
Definition
it can grow in oxygen but prefers no oxygen
Term
what is a spectrum of action
Definition
the range of bacteria an antibiotic can effect, narrow range is only certain bacteria, and broad range is many bacteria
Term
what does the minimal inhibit concentration tell you
Definition
the amount of concentration needed to inhibit the growth of bacteria
Term
how do you know if your looking at a bacteria donor?
Definition
resistance is located on the plasmid, chromosomes will not transfer
Term
what are the 5 characteristics of an enteric?
Definition
-they grow on Mconkey's agar
-they are gram - rods
-they are oxidase negative
-they ferment glucose and lactose
-they are faculatative
Term
what are the 3 possible zones of inhibition that are noted on a mueller hinton agar plate?
Definition
intermediate, succeptible, and resistant
Term
how can you determine if dentrification took place
Definition
it produced bubbles, and you cant continue to use it after bubbles are produced
Term
what is reversion?
Definition
pg 69- after it has eaten up all of the sugar it eats the amino acids which raises the pH and implies its more basic, its called reversion because it goes from red and turns yellow by fermentation of sugar then goes back to red after eating amino acids
Term
What test utilizes reversion
Definition
the KIA test, which is sulfer metabolism. It differentiates between glucose and lactose fermentation
Term
what bacteria is in a chain and what is in a cluster?
Definition
know the term staph, strep, coccus, bacillus
Term
KNOW THE PARTS ON A MICROSCOPE
Definition
Term
what happens when Dna is exposed to UV radiations? How is it repaired and what is it called
Definition
DNA gets thymine dimers, photoreactivation is how its repaired. PG 92
Term
How does UV light not kill endospores?
Definition
endospores have a protective coat that UV light cant penetrate
Term
UNDERSTAND THE PROCESS OF TRANSCONJUGATION
Definition
Term
The total magnification on the 100X is?
Definition
1000X
Term
2.) Put the following steps in order for a Gram Stain (Just put a number next to the following step): (4 points)
i. Flood the stain with Iodine
ii. Flood the stain with Safranin
iii. Flood the stain with Crystal Violet
iv. Create a smear
v. Heat fix 2
Definition
create a smear, heat fix, flood with crystal violet, flood with iodine, flood with safarin
Term
define parfocal
Definition
When using a microscope, you initially focus an object on the lowest objective by first using the coarse focus and finishing with the fine focus. After focusing in this manner on the lowest objective, it is possible to move to the next highest objective and use only the fine focus to focus the object on the next objective. This is due to microscope’s parfocal ability.
Term
What stain will be used in the capsule stain
Definition
India ink
Term
What are 2 beneficial uses of a capsule?
Definition
-avoids phagocytosis
-can stick to surfaces which has a large immunological importance
Term
What are the formulas for dilution factor and total dilution factor?
Definition
Term
What are 3 environmental factors that affect growth rate
Definition
-osmotic pressure
-temperature
-oxygen
Term
Name 2 out of 5 temperatures you incubated your bacteria at to test for optimal growth at varying temperature
Definition
-5
-25
-37
-42
-55
Term
at what temperature does Seretia Marcescens have a pinkish pigment
Definition
25
Term
If you have isolated an enteric, what temperature is it likely to grow best at?
Definition
37
Term
Why should you no shake the TSA tube
Definition
it creates air bubbles which will make the environment no longer anaerobic
Term
Is MSA (mannitol salt agar) selective, differential or both
Definition
both,it is selective for staphylococci and differential for Staphylococcus aureus from other staphylococci. Staphylococci is able to grow on MSA but do not ferment mannitol, so growth appears pink to red. S. aureus ferments the mannitol which produces acid and lowers the ph of a medium. This results in the bright yellow color
Term
what is the chromosomally mediated antibiotic being used for todays experiment?
Definition
Naladixic acid/ rifampton
Term
On what type of agar will the hemolysis experiment be performed on
Definition
blood agar
Term
what is the name of the extracellular matrix that forms in a biofilm
Definition
glycocylax
Term
what is the name of the pigment that Serratia marcescens produces
Definition
Term
what is the name of the type of genetic transfer done for quiz 8
Definition
conjugation
Term
What biosafety level is this micro lab
Definition
2
Term
what does pathogenicity mean
Definition
the ability to cause disease
Term
How do sterilization and disinfect differ
Definition
Sterilization kills everything including endospores. Disinfection does not kill endospores
Term
why would you use a plate instead of broth to grow bacteria
Definition
it allows you to somewhat distinguish between different types of bacateria due to the fact that you can see individual colonies and compare them. YOU CAN ALSO CREATE ISOLATED PURE GENETIC COLONIES.
Term
what is the purpose of using the streak plate method
Definition
to isolate a pure genetic colonly
Term
the only lens that can handle oil is
Definition
100x
Term
gram negative bacteria have more or less peptidoglycan than gram positive bacteria
Definition
less
Term
what is the name of the dye used in the capsule stain
Definition
india ink
Term
name a type of bacteria shape
Definition
cocci or bacillus/ rod
Term
what color is a gram negative bacteria under a gram stain
Definition
pink
Term
what color should your bacteria stain during a gram stain if it is an enteric bacteria
Definition
pink
Term
True/false/neither- if your bacteria was catalase negative, it is an enteric bacteria
Definition
neither, catalase does not affect the status of an enteric
Term
what procedure is done during the protease enzyme to test for these enzymes? if your bacteria is positive for these enzymes, what should your result look like?
Definition
After incubating for 24 hours, you refrigerate your gelatin tube for 5 minutes, a positive result will remain liquid due to the fact that the gelatin was utilized by the bacteria. a negative result will resolidify when frozen.
Term
what 2 things can KIA (kligers iron agar) test for
Definition
-glucose/lactose fermentation
-sulfer reduction
Term
what does a "cracl" in agar indicate
Definition
gas production
Term
explain how to use the metabolic screening chart
Definition
Term
describe a positive rod and negative result for gelatin protease production.
Definition
A positive result will remain liquid due to the fact that the gelatin was utilized by the bacteria. a negative result will resolidify when frozen.
Term
At what temperature are the Streptomyces griseus plates incubated? What is another name for this temperature
Definition
25 degrees. room temperature
Term
what does MIC stand for? explain what it means
Definition
Minimal Inhibitory Concentration- the least amount or lowest concentration of an antibiotic needed to inhibit bacterial growth
Term
in order to create an anerobic environment in the API 20E series, what reagent is added
Definition
Mineral oil
Term
Define bactericidal and bacteriostatic
Definition
bactericidal kills bacteria
bacteristatic inhibits growth
Term
what is the name of the substance produces by S. griseus that smells like dirt
Definition
Geosmin
Term
Explain why the bacteria are put into saline solutions instead of water-hint- we discussed this in class when we put the meat into saline solutions
Definition
Term
1.) Describe the difference between broad and narrow ranged antibiotics
Definition
Term
2.) Why did we put the bacteria into saline solutions for the Muller Hinton plate and API 20E strip?
Definition
Term
3.) What were the three zones of inhibition possible for the Muller Hinton plate?
Definition
succeptible, intermediate, resistant
Term
4.) Why did you not invert the Muller Hinton plate?
Definition
Term
5.) What does the resistance profile of your antibiotic tell you about your bacteria’s ability to cause disease?
Definition
Term
6.) A pyrimidine dimer forms between what two nucleic acids when exposed to UV?
Definition
Term
7.) At what temperature does Seretia Marcescens have a pinkish pigment?
Definition
Term
8.) What three environmental factors are you looking at in lab today?
Definition
Term
9.) Name two of the five temperatures you will be exposing your bacteria to today.
Definition
Term
Why should you not shake the TSA tube?
Definition
Term
What does Serratia marcescens produce?
Definition
Term
Name the five common characteristics of enteric bacteria.
Definition
Gram Negative rods
Grows on Mac. Agar
Anaerobic and Aerobic
Glucose and Lactose Fermentation
Oxidase Negative
Term
2.) Why might catalase production be beneficial to pathogenic (disease-causing) bacteria?
Definition
It can break down catalase into water oxygen which these products are not injurous to bacteria unlink hydrogen peroxide
Term
For the Oxidase Test, what indicates a positive result? If your bacteria is an enteric, what should the result of this test be?
Definition
A positive result is indicated by a purple color change. An enteric should be negative and therefore there should not be a color change.
Term
During the hydrolysis of starch test, what reagent is used? Explain what a positive result of alpha-amylase on the starch plate looks like
Definition
Iodine is the reagent used. On a positive plate, the starch in the plate is broken down by the produced alpha-amylase. Since there is no longer starch in the media, a clearing will form around the bacteria since there is not any starch to form an iodine starch complex. However, further away from the bacteria, where the alpha-amylase has not broken down the starch, the iodine will bind to and the starch and form a purple color.
Term
5.)Explain why we used the process of serial dilution last week. Another way to think of this question is what is the ultimate reason for why we performed this process?
Definition
Ultimately we want to find the stock concentration on the meat. By counting the number of colonies on a plate, it is possible to take the reciprocal of the dilution factor, multiply this by number of colonies, to find the stock concentration.
Term
1.) What is selective media? What is Differential Media? Can a media be both? (2 points)
Definition
Selective media incorporates some compound that will inhibit the growth of some organisms but allow others to grow. Differential media allows you to distinguish between different types of organisms growing on media
Term
2.) What is MSA selective for? What does it differentiate for?
Definition
It is selective for gram negative bacteria and differentiates the lactose non -fermenters (white) from the lactose fermenters (red)
Term
3.) Give a one sentence description of the Metaproject.
Definition
To isolate and identify an enteric bacteria found on the meat product selected
Term
4.) What is the importance of a bacterial plate count in relation to food?
Definition
A higher bacterial count may suggest that the food is unfit to eat and may cause illness
Term
5.) What type of agar will be used to plate the meat?
Definition
Both nutrient agar and macconkey agar
Term
6.) The initial stock concentration of a tube is 4*108 . 10mL is taken from this solution and placed into a second tube containing 90mL already in it. This process is repeated four more times. What is the final concentration of the last tube. For full credit, please show all of your work
Definition
4X10^3
Term
7.) A plate has 200 colonies on it. What is the stock concentration if 10mL was added to 90 mL five times from the stock concentration?
Definition
2X10^7
Term
Is E. coli gram + or -
Definition
Negative
Term
Is B lichen gram + or -
Definition
+
Term
What is the purpose of heat fixation
Definition
Kill the bacteria and stick the smear to the slide
Term
Ex of selective conditions
Definition
Antibiotics, dyes, inhibitory compounds
Term
Ex of differential medium and definition
Definition
Substances that causes bact to take on the appearance that distinguishes it from other bact. Ex: when staphylococcus aureus grows on mannitol salt agar it ferments mannitol changing a pH indicator from red to yellow and other staphylococcus species cannot ferment mannitol so their growth results in no ph change this no color change
Term
What does eosin and methylene blue do to bact?
Definition
Inhibits gram + growth
Term
What is catabolism
Definition
Provide energy needed to drive the bio synthetic (anobolic) reactions required to construct new celles
Term
Aerobic respiration
Definition
Max energy extracted when free oxygen is available as an electron acceptor
Term
Fermentative org
Definition
All yellow culture tube, bubble or no bubble , acid, gas
Term
Faculative org
Definition
Bottom of tube yellow, top 1/2 red, acid
Term
Aerobic org indicating incomplete oxidation of substrate
Definition
Bottom of tube red, top yellow, no bubble no gas,
Term
Aerobic org showing growth
Definition
All red with slight turgidity,
Term
All red and no turgidity
Definition
No reaction and now growth
Term
How to test for hydrolysis of starch
Definition
To Test for amylase flood plate with iodine and allow it to bind with starch. Clear zones indicate positive
Term
Hydrolysis of triglycerides, what's a positive result
Definition
Clearing of emulsion is a positive sign of lipase.
Term
Why do bact produce the enzyme catalase
Definition
Protective factor from the hydrogen peroxide produced during oxygen metabolism. It can rapidly break down hydrogen peroxide into water and oxygen, preventing it from causing any problems. Streptococcus does not produce catalase
Term
What is the enzyme oxidase test for
Definition
Cytochrome oxidase. It occurs in bacteria that carry out respiration where oxygen is the terminal electron acceptor, so the test differentiates between bact that have cytochrome and uses oxygen as final acceptor and those that don't
Term
What was the positive control for nitrate reduction
Definition
B lichen
Term
What was the negative control for nitrate reduction
Definition
M Luteus
Term
How to test for production of nitrate reeducate
Definition
The bact is grown in a nitrate rich medium and the tested for nitrite prescense after incubation. After adding alpha naphthylamine the presence of pink or red indicates presence of nitrites
Term
What is control negative for protease
Control positive
Definition
- is m lutues
+ is b lichen
Term
If gelatin solidifies in protease exp...
Definition
Then no protease, prot -
Term
If gelatin was broke down in protease...
Definition
It liquified and stays liquid it's protease positive
Term
How to test for suffer metabolism
Definition
Looking for presence of h2s by media KIA it tests for fermentation of glucose and lactose
Term
Glucose + lactose
Definition
All yellow
Term
Color of suffer reduction and fermentation
Definition
Black
Term
If gelatin solidifies in protease exp...
Definition
Then no protease, prot -
Term
If gelatin was broke down in protease...
Definition
It liquified and stays liquid it's protease positive
Term
How to test for suffer metabolism
Definition
Looking for presence of h2s by media KIA it tests for fermentation of glucose and lactose
Term
Glucose + lactose
Definition
All yellow
Term
Color of suffer reduction and fermentation
Definition
Black
Term
Suffer + =
Definition
Salmonella= red slant yellow butt
Term
Sulfer -=
Definition
E coli = all yellow
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