Lab Final Exam Flashcards by Ashley Hedrick

What are the two methods for creating isolated colonies on a agar plate

T streak and quadrant streak

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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

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What type of media would you use if you were trying to determine the oxygen requirement for an organism

Fluid thioglycolate medium

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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

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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

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What is the name of the growth container used to check for Capnophilic growth

Candle jar

An aerobe jar

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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

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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

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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

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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

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What is the name of an organism that can grow at high salt concentration

Halophile

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What organisms in the lab can grow in high salt

Staphylococcus: aureus/ epidermis

MSA

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What’s the purpose of heat fixing a slide

Kills the bacteria

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Chains of bacteria are known as

Strepto

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Which 2 bacteria morphologies can form chains

Coccus and bacillus

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Irregular clusters of bacteria

Staphylo

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Which morphology can form irregular clusters

Coccus

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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

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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

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Gram stain

Primary: crystal violet
Counterstain: safranin
Positive: purple
Negative: pink

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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