Lab exam 1: objectives Flashcards
canvas quiz
Long hair must be tied back because _____________________. Select all that apply.
It is a potential source of contamination
It will ruin your microscope.
It would never contaminate cultures
Is a likely target for fire if Bunsen burners are used.
It is a potential source of contamination
Is a likely target for fire if Bunsen burners are used.
The function of agar in the culture media is:
to inhibit the growth of mold
to inhibit the growth of parasites
to act as a solidifying agent
to serve as nutrients
to act as a solidifying agent
You will sample ________ to demonstrate the ubiquitous nature of microbes today. Select all that apply.
the wall
your hands
your desk
your shoe
your head/hair
your hands
your desk
your head/hair
EVEN RELATIVELY “HARMLESS” BACTERIA WHEN CULTIVATED ON A GROWTH MEDIUM, ARE IN SUFFICIENT NUMBERS TO CONSTITUTE A HEALTH HAZARD.
True
False
True
Plates must be ________ and then incubated. Select all that apply.
labeled
shaken
soaked in bleach
inverted
labeled
inverted
Total magnification = magnification by the _____ lens x magnification by the ___lens.
ocular…ocular
objective…objective
ocular…objective
ocular…objective
Read the instructions for using the microscope carefully. _________ is used for cleaning the condenser and objective lenses.
A paper towel
A kim wipe
Blotting paper (bibulous paper)
Lens paper
Lens paper
When you start, the condenser should be nearly even with the stage and the iris diaphragm should be open.
True
False
True
Parfocal means that the _______________________. If you don’t remember this, please review what you learned about microscopes in your general biology class or research online.
image will move out of focus as you increase magnification
image should remain mostly in focus as you increase in magnification
the course focus will need to be adjusted
the course focus will be necessary
image should remain mostly in focus as you increase in magnification
Before advancing to a higher objective, the specimen must be _____________.
Select 2 choices.
in focus
centered
out of the center
to the right on the slide
in focus
centered
If you are working with a bacterial smear, you must use the ________lens in the final step.
scan
low power
40X
oil immersion
oil immersion
It is extremely important to work through the 10X, then 40X objectives, adjusting the fine focus and lighting for each before advancing to oil immersion.
True
False
True
The scan, 10X and 40X lenses and other parts of the microscope should not get any oil on them.
True…This is very important
False…All lenses should be used with oil
True… This is very important
The stage should be moved down to add oil to the slide.
True
False
False
To remove the oil from the lenses, ______ should be used.
a kim wipe
bibulous paper
a paper towel
lens paper
lens paper
You have a used, unbroken test tube to discard since you have opened it and it is no longer sterile. Where will you place the test tube?
In the garbage can.
Leave in rack and place in discard window.
Back up front in the racks with other sterile test tubes.
In the red or orange biohazard bags.
Leave in rack and place in discard window.
Where do you discard your used agar plates, swabs, and other contaminated non-sharp items?
In the regular trash cans.
In the biohazard bags.
In the brown baskets at the front of the lab.
In the front of the lab by the other sterile petri dishes.
In the biohazard bags.
When do safety goggles need to be worn in the lab? Select 3 choices.
When looking through the microscope.
When staining bacteria.
When working with any chemicals in the lab.
When working with live bacteria in tubes or plates.
When staining bacteria.
When working with any chemicals in the lab.
When working with live bacteria in tubes or plates.
Where is the fire extinguisher in our lab?
Right next to the first aid kit.
In a cabinet on the side of the lab.
By the hooks where backpacks and coats are stored.
At the front of the lab by the prep room.
At the front of the lab by the prep room.
Which of the following should you do if you need to leave the room in the middle of a lab? Select 5 choices.
Leave your gloves on.
Leave your lab coat on.
Remove your lab coat.
Remove your gloves.
Don’t wash your hands.
Take your plates home with you.
Wash your hands.
Remove your lab coat.
Remove your gloves.
Don’t wash your hands.
Take your plates home with you.
Wash your hands.
When should you clean your lab bench with disinfectant? Select 3 choices.
Only once at the start of lab.
If you have a spill or splatter of bacteria.
Only once at the end of lab.
Never since the lab technician cleans the benches each day.
At the start of lab after you put on gloves.
At the end of lab when you are still wearing your gloves.
If you have a spill or splatter of bacteria.
At the start of lab after you put on gloves.
At the end of lab when you are still wearing your gloves.
Where do you discard used microscope slides?
The sharps container.
The red biohazard bag.
The regular trash can.
In your garbage at home.
The sharps container.
Tubes must be carried in _______ to avoid carrying them in handfuls which could lead to spills.
by the caps
plastic baggies
sharps containers
racks
racks
If you have a spill or a splatter, what are the correct steps in order for cleaning?
cover the spill with a paper towel, soak with disinfectant for 5 minutes, discard materials and contaminated gloves in the biohazard bag
cover the spill disinfectant, wipe with a paper towel, discard materials and contaminated gloves in the biohazard bag
cover the spill with a paper towel, soak with disinfectant for 20 minutes, discard materials and contaminated gloves in the biohazard bag
cover the spill with a paper towel, soak with disinfectant for 20 minutes, discard materials and contaminated gloves in the biohazard bag
What could happen if you work directly over your books rather than the lab bench? Select 3 choices.
Your book could be ruined if bacteria are spilled on it.
If you have a spill, you can take a contaminated book out of the lab without
autoclaving it.
You could have a spill on your books
If you spill on your book, it will have to be autoclaved before it leaves the lab.
Your book could be ruined if bacteria are spilled on it.
You could have a spill on your books
If you spill on your book, it will have to be autoclaved before it leaves the la
Your lab coat must be buttoned in case of a spill.
True
False
True
If you see rods under the microscope, the morphology is:
Bacillus
Coccus
Staphylo
Strepto
Bacillus
Bacteria have a ____________________________ surface.
positively-charged
uncharged
negatively-charged
negatively-charged
If you see spheres under the microscope, the morphology of the bacteria is:
Bacillus
Staphylo
Coccus
Strepto
Coccus
If you look in the microscope and see chains of organisms, the prefix is termed:
bacillus
staphylo
clusters
coccus
strepto
strepto
If you look in the microscope and see clusters of organisms, the prefix is termed:
strepto
spirals
coccus
staphylo
chains
staphylo
If you see rods under the microscope, the morphology is:
Bacillus
Coccus
Staphylo
Strepto
Singles
Bacillus
The name of the dye used in the negative stain is ________ and it is ________________.
Nigrosin….acidic
Methylene blue….basic
Nigrosin…..basic
Crystal Violet….acidic
Methylene blue…..acidic
Nigrosin….acidic
Bacteria have a ____________________________ surface.
positively-charged
negatively-charged
negatively-charged
The negative staining technique is used to: choose 2
determine morphology and cellular arrangement that are too delicate to withstand heat-fixing
determine the accurate size since there is minimal cell shrinkage
identify acid-fast organisms
differentiate gram-negative organisms
determine morphology and cellular arrangement that are too delicate to withstand heat-fixing
determine the accurate size since there is minimal cell shrinkage
If you look in the microscope and see chains of organisms, the prefix is termed:
bacillus
staphylo
clusters
coccus
strepto
strepto
If you look in the microscope and see clusters of organisms, the prefix is termed:
strepto
spirals
coccus
staphylo
chains
staphylo
The dye we will use for the negative stain is called________, and it will stain the _____.
Crystal violet…cells
Safranin…background
Nigrosin…background
Malachite green….cells
Nigrosin….background
A colony forms where an original cell or colony-forming unit is deposited on a solid nutrient medium. The cell divides to eventually form a visible mass of cells.
True
False
True
Streak Plate Technique: Why should the lid be used as a shield during the streak plate method?
To prevent airborne contamination
To avoid misplacing it
The lid should not be used as a shield
To keep the loop warm
To prevent airborne contamination
A use of the streak plate technique is to:
obtain isolation of individual species from a mixed sample
heavily grow the organisms
obtain a mixed culture
obtain isolation of individual species from a mixed sample
How many times will you dip into your original culture when performing a streak plate?
3 times
2 times
only once, to streak the first region.
only once, to streak the first region.
Before leaving the lab each day, you need to _______ to be in compliance with the safety rules. Select 2 choices.
smile and give a sigh of relief
disinfect your lab bench
wash your hands
disinfect your lab bench
wash your hands
Organisms and chemicals must never be ___________.
examined in the laboratory
labeled in the laboratory
removed from the laboratory
opened in the laboratory
removed from the laboratory
Which of the following must not be done or worn in the laboratory? Select 4 choices.
wear a used lab coat out of the laboratory
wear gloves out of the laboratory
open-toed shoes or sandals
apply cosmetics
all the above
It is acceptable to ______ in the laboratory.
throw broken glass in the regular trash can
lay down culture tubes on the table
mouth pipette
place used microscope slides in a “sharps” container
place used microscope slides in a “sharps” container
Your workspace needs to be disinfected:
only after working
every 15 minutes
before and after working
only before working
before and after working
Mannitol Salt Agar(MSA): Mannitol Salt Agar is _______ and is used for the isolation of ____________.
Selective….. Staphylococcus aureus
Selective and Differential ……..Staphylococcus aureus
Enriched …..Escherichia coli
Differential….Escherichia coli
Enriched and Differential …. Staphylococcus aureus
Selective and Differential ……..Staphylococcus aureus
MSA contains the carbohydrate ____________. The high NaCl concentration favors the growth of staphylococci and _______ the growth of other organisms.
mannitol….increases
lactose….increases
glucose…inhibits
glucose…increases
mannitol..inhibits
mannitol..inhibits
Sheep Blood Agar: If complete clearing around the colonies appears, the hemolysis is:
gamma
alpha
beta
beta
Sheep Blood Agar: If no clearing around the colonies appears, the hemolysis is:
beta
alpha
gamma
delta
gamma
Coliforms are normal gram-_______ inhabitants of the human ________.
positive…skin
negative…skin
positive…intestinal tract
negative…intestinal tract
negative…intestinal tract
Phenylethyl alcohol agar (PEA) is mostly selective for _________ organisms. This is because PEA inhibits the growth of many Gram-negative while only some Gram-positive organisms. PEA is _________________.
Gram-positive….selective and differential
Gram-positive….selective only
Gram-negative…selective and differential
Gram-negative…selective only
Gram-positive….selective only
MacConkey agar is:
selective and differential
enriched and differential
selective only
differential only
selective and differential
A hot pink color was observed on colonies growing on MacConkey agar. These organisms are capable of _______________ fermentation.
glucose
lactose
sucrose
galactose
lactose
Mannitol Salt Agar: If an organism grows on this agar and ferments mannitol, the appearance will be:
Red growth with no halo
Yellow growth or halo
Yellow growth or halo
Mannitol Salt Agar: The name of the selective agent in this medium is:
bile salts
mannitol
NaCl
crystal violet
NaCl
Blood Agar: If a greenish appearance is observed on blood agar, the hemolysis is:
alpha
gamma
beta
alpha
Blood Agar: Blood agar is:
Enriched (will grow fastidious organisms) and Differential (organisms may look different)
Enriched
Selective
Differential
Enriched (will grow fastidious organisms) and Differential (organisms may look different)
Incinerators need to warm up for ________ prior to using. The loops need to be heated in the incinerators for ______________.
5 minutes….1 minute
7 seconds….10 minutes
10 minutes….7 seconds
10 minutes….2 seconds
10 minutes….7 seconds
If you see spherical shaped organisms under the microscope, the morphology of the bacteria is:
Singles
Coccus
Staphylo
Strepto
Coccus
Bacteria have a _________ surface.
positively-charged
uncharged
negatively-charged
negatively-charged
If you look in the microscope and see clusters of organisms, the prefix is termed ________.
strepto
staphylo
chains
spirals
staphylo
Purple organisms observed on a Gram stain are:
Gram-positive
Gram-negative
Gram-positive
Red organisms observed on a Gram stain are:
Gram-negative
Gram-positive
Gram-negative
The name of the decolorizer is:
Gram’s iodine
95% alcohol (same as 95% ethanol)
acid-alcohol
95% alcohol (same as 95% ethanol)
The Gram stain is a(n):
differential stain
acid-fast stain
simple stain
differential stain
Red color is observed all throughout the growth medium in a motility test. Is this organism motile?
No
Yes
Yes
Is an organism that remains along the stabline motile?
No
Yes
No
Motility test medium is inoculated with a:
both a loop and a needle
needle
loop
either a loop or a needle
needle
An organism appears reddish/purple/hot pink following an acid-fast stain. Is this organism acid-fast?
Yes
No
Yes
The substance called _________________ causes this organism to be acid-fast.
phospholipids
mycolic acid
lipid A
peptidoglycan
mycolic acid
Which of the following organisms may be acid-fast? Select 2 choices.
Mycobacterium leprae
Mycobacterium tuberculosis
Staphylococcus aureus
Escherichia coli
Mycobacterium leprae
Mycobacterium tuberculosis
The acid-fast stains are used:
as a rapid, preliminary diagnosis of tuberculosis
to track the progress of antibiotic therapy in tubercuolosis patients
determine how contagious a person with tuberculosis is
All of the choices are correct.
All of the choices are correct.
Do endospores appear as green ovals or spheres?
No
Yes
Yes
Only a few genera produce endospores. Among them are the genera:
Bacillus and Clostridium
Staphylococcus and Escherichia
Bacillus and Staphyloccocus
Clostridium and Escherichia
Bacillus and Clostridium
The spore stain may be useful for patients with___________. Select 4 choices.
tetanus
gas gangrene
pseudomembranous colitis
botulism
tuberculosis
tetanus, gangrene, pseudomembranous colitis, botulism.
The first stain you will need to apply to your smear is called ____.
Safranin
Crystal Violet
Malachite Green
Methylene Blue
Malachite Green
Growing vegetative cells on your endospore stain will appear ___________________.
Yellow
Red
Purple
Green
Red
The mode of action of chloramphenicol is:
cell wall inhibitor
plasma membrane inhibitor
metabolic inhibitor
protein synthesis inhibitor
protein synthesis inhibitor
The mode of action of ciprofloxacin is:
metabolic inhibitor
cell wall inhibitor
DNA replication inhibitor
plasma membrane inhibitor
DNA replication inhibitor
The mode of action of trimethoprim is:
protein synthesis inhibitor
inhibits folic acid synthesis which inhibits purine and pyrimidine synthesis
cell wall inhibitor
inhibits folic acid synthesis which inhibits purine and pyrimidine synthesis
Which of the following antibiotics would be effective against fungi?
Chloramphenicol
treptomycin
Tetracycline
None of the choices since fungi are eukaryotic
None of the choices since fungi are prokaryotic.
None of the choices since fungi are eukaryotic
The mode of action of penicillin is
cell wall inhibitor
metabolic inhibitor
plasma membrane inhibitor
protein synthesis inhibitor
cell wall inhibitor
Antimicrobial susceptibility testing is a standardized testing method used to measure the effectiveness of antibiotics and other chemotherapeutic agents on pathogenic microbe. It is often an essential tool in _____.
prescribing appropriate treatment
killing all pathogens
identification of microbes
prescribing appropriate treatment
Each lab team will need a total of _________ plates.
4
8
6
2
8
_____ of sterile water will be added to tubes 1 and 2. Then, ______ of water will be added to tubes 3,4, and 5. They must be kept covered.
990 microliters….900 microliters
900 microliters….990 microliters
10 microliters….100 microliters
990 microliters….900 microliters
When preparing dilution tube 4, ______ from dilution tube ____ will be transferred and then mixed well.
100 microliters…tube 4
10 microliters…tube 4
10 microliters….tube 3
100 microliters…tube 3
100 microliters…tube 3
After the original broth culture is mixed, you will aseptically transfer ___ to dilution tube 1 and then mix well.
10 microliters
900 microliters
990 microliters
100 microliters
10 microliters
In order to plate the bacteria, _______ from the dilution tubes will be aspeptically transferred to a plate.
900 microliters
990 microliters
100 microliters
100 microliters
A standard plate count is an indirect means of estimating microbial _____ of a liqud sample using the number of ________ that a portion of the sample produces when spread onto an agar plate.
colonies…..actual cells under the microscope
cell density….actual cells under the microscope
colonies…cell density
cell density….colonies
cell density….colonies
A countable plate is one that contains between ____________ individual colonies.
30-300
30-200
20-200
10-300
30-300
A serial dilution is a series of controlled transfers-several small dilutions, each one compounding the previous on until the sample is reduced to one millionth or less of its original density. Diluting a sample does the following 2 important things:
systematically increases cell density….can mathematically link the unknown origianl cell desnity with the known number of colonies on the plate
systematically decreases cell density….can mathematically link the known original cell density with the known number of colonies on the plate
systematically decreases cell density….can mathematically link the unknown original cell density with the known number of colonies on the plate
systematically decreases cell density….can mathematically link the unknown original cell density with the known number of colonies on the plate
If 2 mL of broth is being diluted (V1) by combining it with 8 mL of diluent, what is the dilution factor?
2/10
1/10
1/8
2/8
2/10
