Lab Final Exam Flashcards
What are the two methods for creating isolated colonies on a agar plate
T streak and quadrant streak
If you forget to sterilize your little between each section while streaking for isolation what would you predict your plate would look like after inoculation
Growth all over the plate with no isolated colonies
What type of media would you use if you were trying to determine the oxygen requirement for an organism
Fluid thioglycolate medium
Bacteria growing and fluid thioglycolate broth growing half an inch below the surface
Microaerophile: Require oxygen to survive, require environments contain lower levels of oxygen than the atmosphere
What growth patterns can you expect in thioglycolate medium?
Obligate aerobe: must use O2
Obligate anaerobe: must avoid o2
*Facultative anaerobes: can grow with it without O2
*Aerotolerant anaerobes: no metabolic o2 requirement but can tolerate.
Microaerophile: Require oxygen to survive but require environments that contain lower levels of oxygen in the atmosphere
What is the name of the growth container used to check for Capnophilic growth
Candle jar
An aerobe jar
What are the four major thermal classifications of bacteria
Psychrophile: icy waters 10-20 degrees
Mesophile: body temp 37-45 degrees
Thermophiles: hot springs 60-80 degrees
Hyperthermophiles: ocean vents, above boiling
Predict the outcome of growing a psychrophile at 65 Celsius and predict the outcome of going in Mesophile at 37 success
A psychrophile would not grow at 65°C
Mesophile at 37 will thrive and grow very well
What are the three major classifications of bacteria based on the pH In which they grow
Acidophiles: below ph 2.0
Neutrophils: 6.5-7.5 ph
Alkaliphiles: 8.5-11ph
Predict the outcome of growing an alkaphilic bacteria at a pH of 9.0 and predict the outcome of growing and acidophilic bacterium at PH9 point
Alkaliphiles at 9.0 would grow very well
Acidophiles at 9.0 would not grow at all
What is the name of an organism that can grow at high salt concentration
Halophile
What organisms in the lab can grow in high salt
Staphylococcus: aureus/ epidermis
MSA
What’s the purpose of heat fixing a slide
Kills the bacteria
Chains of bacteria are known as
Strepto
Which 2 bacteria morphologies can form chains
Coccus and bacillus
Irregular clusters of bacteria
Staphylo
Which morphology can form irregular clusters
Coccus
If you use a basic dies and perform a simple stain would you expect the cell to be the same color as the dye or would it be colorless and why
The same color as the dye, because the bacteria is slightly negative and so they are attracted to the positive chromophore of the basic dye
If you performed a negative stain on a bacterium which stain would you use and what would be the color bacteria and the color of the background
Eosin or nigrosin, bacteria would be colorless. Background would be dark/ black
Gram stain
Primary: crystal violet
Counterstain: safranin
Positive: purple
Negative: pink
Acid fast stain
Primary: carbol fuschin
Counterstain : methylene blue
Positive: pink
Negative blue
Endospore stain
Primary: malachite green
Counterstain: safranin
Positive: green spores present
Negative: all pink
What microscopy technique would you use to determine motility
Hanging drop method
What is the function of a mordant and what is the mordant for Gram stain
Grams iodine, it is used to hold down the molecules of a stain onto a micro organism increasing staining ability
Mannitol salt agar (MSA)
Halophile
Positive = turns yellow
Negative = stays red
MacConkey agar
Used for gram negative lactose fermenting organisms.
Positive for lactose: pink (ex. E. Coli)
Non lactose: colorless/ yellow
Eosin methylene blue (EMB) agar
Selective: for gram negative Differential: for lactose and non lactose fermenting. Positive for lactose : dark black/ pink Negative lactose: colorless Metallic green: e. Coli
Hektoen agar
Salmonella and shigella Uninoculaed: green Selective: gram negative Differential: lactose fermenting Yellow/orange: + lactose (e.coli) Clear growth : shigella Black: hydrogen sulfide production (salmonella)
Xylose lysine deoxycholate (XLD) agar
Salmonella and shigella Selective: gram negative Yellow: e. Coli (lactose +) Black: salmonella Red: shigella
What color does this medium turn on an organism for men’s the sugar and the medium phenol red carbohydrate broth (PR glucose, lactose etc.)
Yellow= positive fermenting
What color is the medium on an organism does not use the sugar
Red= negative fermenting
What is the purpose of the Durham tube
Gas production
Which 2 reagents are used to test for the VP results ? What color is a positive result?
Vp reagent A/ VP reagent B
Red= positive (small layer at top)
What reagent would you use to determine if an organism is catalase positive or negative and what would each result look like?
Hydrogen peroxide
Bubbles +
No bubbles -
Which test may require the addition of zinc powder to determine the final results.
Nitrate reductase media
If you add zinc powder to the medium and it changes to red is this positive or negative result
Negative
Is citrate medium broth or agar? What does this positive citrate result look like
Agar
positive =blue
Negative = green ( if green but has growth = positive)
For decarboxylase test ADC, LDC, ODC What must you add to the top of the broth after inoculation? What color with the test turn if the organism can decarboxylate an amino acid
Mineral oil
Purple
Which test requires you to add to a present iron chloride (FeCl3) ? if your test turns green is a positive or negative result?
Phenylalanine deaminase (PDA) Green = positive
What color is a positive urease test?
Pink
What color is a positive bike esculin test (BEA)?
Dark brown almost black = positive
Tan = negative
What are the three things SIM medium can be used to determine
Motility, indole production , sulfur reduction
If you add a Kovacs reagent to sim medium what would you be testing for and what color is a positive result
Indole production
Pink= positive
If your sim is cloudy it is positive for
Motility
If your sim is black
Sulfur reduction
What is the difference between Alpha Beta Gamma hemolysis
Alpha is the partial destruction of our blood cells
beta is the complete destruction and gamma does not involve any breakdown
What place is used to determine if a strain of bacteria is hemolytic or not
Blood agar plate (BAP)
Which organisms would you be trying to confirm with coagulate test
Staphylococcus aureus
Name and describe the method used to determine anabiotic susceptibility for bacterium
Disk diffusion method (the Kirby Bauer method)
Anabiotic desks diffuse into Mueller Hinton agar potentially inhibiting bacterial growth
* zone of inhibition indicates bacteria could not grow and presence of antibiotics
*resistance it will grow fine
*intermediate sort of kills it
*sensitive large zone of inhibition
A small circular piece of DNA got the plasma can be put into a bacterium using which technique
Transformation
What was the purpose of growing bacteria transformed with Pglo on plates that contained ampicillin
They are naturally ampicillin resistant so the ones that have picked up the plasmid are now going to grow on the ampicillin plate
What is the purpose of growing bacteria transformed with P glow and plates that contained arabinose
If you add arabinose sugar they’re going to make that glowing fluorescent pro Tien
