Lab Exam - UCA Microbiology Wainwright

positive pressure suits

Which safety feature usually reserved for when working with extremely dangerous microbes is not located in our lab room?

goggles

_______ are to be worn in the microbiology lab at all times.

biohazard trash cans

Where should disposable plastic petri dishes be placed at the end of lab?

handled by the instructor only

Broken glass that is potentially contaminated with microbes should be _______.

electronic compound brightfield microscopes

What kind of microscopes do we use in our lab?

1000x

What is the total magnification of a specimen viewed through the 100x objective lens after passing through the 10x ocular lens?

100x

What is the total magnification of a specimen viewed through the 10x objective lens after passing through the 10x ocular lens?

light intensity

The rheostat of the brightfield microscope allows for adjustment of

Congo red

Which reagent is needed to perform an acidic simple stain?

white

If a basic simple stain is performed, what color would you expect the background to be when viewed in the microscope?

gram stain procedure

a staining procedure that differentiates bacteria based upon the thickness of the cell wall and the presence or absence of a lipopolysaccharide outer membrane; helps us differentiate G+ and G- bacteria

iodine

In a gram stain procedure, which reagennt is the mordant?

mordant

a chemical substance that sets the stain onto a specimen, ensuring that the dye adheres properly and does not wash away during the staining process; helps to intensify the color of the primary stain and make it more permanent

Capsules resist phagocytosis

A staining procedure is performed and a bacterium is seen to have a capsule. Why is this important?

phagocytosis

the process by which phagocytes engulf other cells, particles and even pathogens, acting as the clean up system for the organism

mycolic acid

If a certain bacteria’s cell wall contains ____________, the cell wall may repel anti-bacterial medications and resist phagocytosis.

clostridium

Which bacterial genus is known to release endospores?

safranin

The secondary, or counter stain, used in the Schaffer Fulton test is

the proper nutrients be available

The growth of most normal flora bacteria requires that

spectrophotometer

an instrument used for detecting the presence of any light-absorbing particles dissolved in a solution and for measuring the concentration of those particles; this helps us determine if any bacterial growth has occurred

to encourage their reproduction

Why are microbes placed in an incubator following inoculation of a medium?

decrease the density of the bacterial population

What does serial dilution do?

filtration

What physical agent for controlling microbial growth was not tested?

salt 20%

Which agent proved to be the most successful in controlling microbial growth?

quadrant streaking

What method is used to separate out the microbes present in a mixture?

little yellow buttery rods

Colony characteristics are described as punctiform, yellow, and butyrous

perform a quadrant streak for the colony being examined

If, after quadrant streaking, the gram stain shows a mixture of 2 microbial types, what shoudl be done.

hydrogen peroxide

Which reagent is used to test G+ cocci for catalase production?

(original number of bacteria ) * 2^(generation time)

What is the formula for calculating bacterial growth based on generation time?

100 × 2^4

10^9

If the serial dilution is based on normal dimensions, what number should you multiple the end colony count to obtain the number of bacteria in the original flask?

at optimum temperature

Bacteria reproduce most rapidly when

the UV light is bactericidal

What is the effect of UV light on bacterium?

bactericidal

term meaning capable of killing bacterium

dehydration

Increasing the osmotic pressure has what effect on bacteria

staphylococcus aureus

Which bacterium exhibits the greater salt tolerance?

decrease the rate of reproduction

Refrigerating a population of bacteria has what effect

hydrogen peroxide

What chemical is an antiseptic?

berries

Under the microscope, a cocci bacterium looks like

rods

Under the microscope, a bacillus bacterium looks like

waves

Under the microscope, a spirila bacterium looks like

purple

After performing a Gram stain and viewing under the microscope, a G+ bacterium appears

pink

After performing a Gram stain and viewing under the microscope, a G- bacterium appears

they have few layers of peptidoglycan

A sample from a colony is found to be G- rods. What does this mean?

green

A G+ coccus is catalase negative and alpha hemolytic. The sheeps blood agar plate would turn

neutralizes hydrogen peroxide

A bacterium releases catalase. What does this do?

motility, indole, hydrogen sulfide production

A SIM deep was used to assess

If the patient is a child or is pregnant

What would be the most likely reason a doctor would not prescribe tetracycline?

antibiotic susceptibility

The Kirby Bauer disk diffusion test is used to assess

autoclaved

Reusable materials such as glass tubes should be _________ between uses.

inoculate a medium

An inoculation loop is used to

agar

a gel-like substance that is rich in nutrients that bacteria like but cannot be completely consumed by them; often used to grow and study bacteria

yeasts have membrane bound organelles

Yeast differs from bacteria in that

pink-red

If a bacterium is found to be indole positive, the kovac reagent turned

tabletop biohazard container

Where should pipettes, hockey sticks, and cotton swabs be put after lab?

ocular lens

What is the name of the eyepiece of the microscope?

objective lens

What is the name of the three rotating magnifiers of the microscope?

stage

What is the name of the platform where the slide is placed for viewing on a microscope?

stage clip

What is the name of the adjustable metal piece that keeps a slide in place as you are viewing it on a microscope?

aperture

What is the name of the hole on the stage that lets light through on a microscope?

illuminator

What is the name of the light source on a microscope?

course adjustment

What is the name of knob on a microscope that helps big adjustments?

fine adjustment

What is the name of knob on a microscope that helps little adjustments?

stage controls

What is the name of knobs on a microscope that moves the stage back and forth?

negatively charged

The bacterial cell wall is __________ (negatively/positively) charged

acidic (negative) stain

stain in which a negatively charged stain is used and repelled; this causes the bacterium to appear white against a background that is the color of the stain; involves innoculating the stain and then smearing the liquid across the entirety of the slide

common stains used for this include congo red, nigrosin, and India ink

congo red, nigrosin, india ink

What are the three negative stains commonly used in simple stains?

basic (positive) stain

stain in which a positively charged stain is used and attaches to the cell wall; the bacterium takes on the color of the stain and the background is white

common stains used include methylene blue, crysatl violet, malachite green, safranin

Methylene Blue, Crystal violet, Malachite Green, safranin

What are the four positive stains commonly used in simple stains?

1) place a drop of distilled water on the center of the slide 2) flame sterilize an inoculating loop 3) inoculate the water with a smidge of bacteria 4) allow to air dry 5) heat fix the specimen 6) stain the specimen 7) rinse with distilled water 8) blot dry with Kimwipe 9) view at 1000x

What are the basic steps involved in most staining procedures?

Gram differential stain

stain which is used to differentiate between G+ and G- bacteria; cover heat fixed specimen with Crystal violet, Gram’s iodine, ethanol, and Safranin

Crystal violet, Gram’s iodine, ethanol, and Safranin

When performing the Gram differential stain procedure, what four things should you cover the heat fixed specimen with to stain and counterstain the specimen?

acid fast bacilli

We use the Kinyoun Method for staining and viewing ____________.

mycobacterium smegatis

What is the acid fast bacilli we used in our lab to learn the Kinyoun method?

cheek cells

While doing the Kinyoung method, we mixed __________ with the Mycobacterium smegmatis.

the acid fast bacilli will be red, the cheek cells will be blue

After doing the Kinyoung method, what colors will the acid fast bacilli and cheek cells be?

carbolfuschin, acid alcohol, methylene blue

What are the three things used to cover and stain a heat fixed bacterium in the Kinyoun Method for staining acid fast bacilli?

20 minutes

How long should carbolfuschin sit on the heat fixed bacterium in the kinyoun method for staining acid fast bacilli?

Schaeffer-Fulton test

a stain test that is meant to reveal bacterial endospores; involves placing a heat fixed slide on top of a beaker with boiling water, covering it with a strip of paper towel, keeping the power towel wet with malachite green, rinsing with water, and counter staining with safranin

bacterial endospores

What does the schaeffer-fulton stain test for?

malachite green and safranin

What are the two stains used in the schaeffer-fulton test, in order?

endospores will be green, normal bacteria will be red/pink

After doing the Schaeffer-fulton test, what colors will endospores and normal bacteria be?

pink or red

What color does the safranin stain make bacteria?

vortex

an instrument used to swirl liquid in a test tube through rapidly oscillating movement, thoroughly blending liquids and suspensions; it helps break up bacteria pieces

Escherichia coli

What bacteria did we learn serial dilution with?

heat, cold, UV light, osmotic pressure, pH

What were the five physical agents we tested for their effectiveness on controlling microbial growth?

95 degrees

At what temperature did we test for heats effectiveness on controlling bacterial growth in 30 minutes?

4 degrees

At what temperature did we test for colds effectiveness on controlling bacterial growth in 30 minutes?

aluminum foil

When testing the effectiveness of UV light on controlling bacterial growth, cover half of the plate with __________ to create a control section that won’t be effected at all in 30 minutes.

osmotic pressure

the pressure required to prevent the movement of water across a semipermeable membrane separating two solutions with different solute concentrations, which is influenced by the salt concentration

0.5%, 5%, 10%, 20%

What were the four percentages of salt plates we used to test the effect of osmotic pressure on controlling the bacterial growth?

we took the absorbance reading for each of the different inoculated pH tubes using the spectrophotometer

How did we test for the effectiveness of pH on controlling the growth of bacteria?

pH 3, pH 5, pH 7, pH 9

Which four pHs did we test their effectiveness in controlling bacterial growth?

disinfectant

chemical agent meant to control bacterial growth that is not human safe; ex: clorox bleach, great value bleach, hexal

antiseptic

chemical agent meant to control bacterial growth that is human safe; meant to prevent bacterial infection usually on the skin; ex: listerine mouthwash, crest prohealth mouthwash, hydrogen peroxide

antibiotic

chemical agent used to kill existing bacteria and prevent further growth that is human safe; meant to get rid of preexisting infection

listerine mouthwash, crest pro health mouthwash, hydrogen peroxide

What three antiseptics did we test in lab for their effectiveness in controlling microbial growth within 30 minutes?

clorox bleach, great value bleach, hexal

What three disinfectants did we test in lab for their effectiveness in controlling microbial growth within 30 minutes?

Mueller-Hinton plate + 6 antibiotic disks

What did we use to test the effectiveness of certain antibiotics in killing bacterial growth?

Ampicillin (AMP), Tetracycline (TE), Polymxxin B (PB), Gentamicin (GM), Erythromycin (E), Chloramphenicol (C)

What are the 6 antibiotics used in lab in combination with the Mueller-Hinton plate to test their effectiveness in killing bacterial growth?

hydrogen peroxide

What is the most practical and effective chemical agent for controlling bacterial growth (because it is the most effective one that won’t damage what you are trying to clean)?