Lab 1 Flashcards by Unknown Unknown

What will a slant look like if it’s sterile?

Contaminated?

Sterile = no growth on the surface
Contaminated = growth on surface

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Provides a sturdy flat surface to support/steady the microscope

Base

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Located in the base. The light from the lamp passes directly upward through the microscope

Substage light

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Located on the base or arm. This dial allows you to adjust the intensity of the light passing through the specimen

Light control

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The platform that the slide rests on while being viewed

Stage

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Holds the slide in position for viewing and has two adjustable knobs that control the precise movement of the slide

Mechanical stage

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Small non-magnifying lens located beneath the stage that concentrates the light on the specimen

Condenser

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A shutter within the condenser that can be controlled by a lever to adjust the amount of light passing through the condenser

Iris diaphragm lever

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Allows you to make large adjustments to the height of the stage to initially focus the specimen

Coarse adjustment knob

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Used for precise focusing once the initial coarse focusing has been completed

Fine adjustment knob

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Attaches to the nosepiece to support the objective lens system. Also provides attachment of the eyepieces which house the ocular lens.

Head

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Vertical portion of the microscope. Connects the base and the head.

Arm

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Rotating mechanism connected to the head. Generally carries four objective lenses.

Nosepiece

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Attached to the nosepiece

Objective lenses

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4 objective lenses:

Scanning (4x)
Low-power (10x)
High-power (40x)
Oil immersion (100x)

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The part of the microscope that magnifies the image produced by the microscope’s objective so that it can be seen by the human eye.

Magnification power of 10x

Ocular lens

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The measure of a len’s ability to capture light from the specimen and use it to make the image is called the ____ _____

numerical aperture

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Order of threads

Top- red
Middle- blue
Bottom- yellow

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Explain what the letter E looked like microscopically

The e flips upside down and backwards when viewed on a microscope

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Total magnification for each objective lens

Scanning (4x) = 40x
Low-power (10x) = 100x
High-power (40x) = 400x
Oil immersion (100x) = 1000x

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Define resolution

The clarity of an image

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Define limit of resolution

The actual measurement of how far apart 2 points must be for the microscope to view them as separate

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As the limit of resolution is made smaller, the resolution

improves

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Colony Morphology- shape

circular
rhizoid
irregular
filamentous

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Colony Morphology- margin

(margin is the outer edges) entire undulate lobate filamentous

Colony Morphology- elevation

flat raised convex umbonate

Colony Morphology- size

punctiform small moderate large

Colony Morphology- texture

smooth rough

Colony Morphology- appearance

shiny dull

Colony Morphology- pigmentation

nonpigmented (cream, tan, white) pigmented (purple, red, yellow)

Colony Morphology- optical property

opaque transparent/translucent

BSL-1

-minimal threat -standard microbiological practices (PPE; coat, gloves, eyewear)

BSL-1 example

*Bacillus Subtilis*

BSL-2

-moderate health risk -**recommended** to work in a biological safety cabinet (to minimize splash) -coat, gloves, eyewear, and **facemask**

BSL-2 example

Salmonella

BSL-3

-serious/lethal disease -**required** to work in a biological safety cabinet -coat, gloves, eyewear, facemask, and **respiratory protection**

BSL-3 example

Rabies virus

BSL-4

-lethal/life-threatening -lab access restricted, shower in/out -special ventilation systems -required to work in a biological safety cabinet -full body PPE (air-supplied pressure suit)

BSL-4 example

Ebola virus

Compare 0 to 4

0 is good, 4 is bad

Color coding for a chemical hazard label

Blue: health hazard Red: fire hazard Yellow: reactivity

How is a spill cleaned?

1. Cover any culture spills with paper towels. 2. Soak the towels immediately with disinfectant and allow them to stand for **20** minutes. 3. Report the spill to your instructor. 4. When you are finished, place the towels in the container designated for autoclaving.

What disinfectant is used in our lab?

10% bleach

What agent was the best at controlling microbes?

Benzalkonium

What agent was the worst at controlling microbes?

Triclosan

What is the mechanism of action of triclosan? Which types of microbes did this control?

-Fatty acid biosynthesis -Antiviral, antifungal

What is the mechanism of action of Chlorhexidine? Which types of microbes did this control?

-Destroys the cell membrane -Antiviral, antiprotozoal, antibacterial, and antifungal

What was the purpose of plates 7 and 8 described in the procedure for exercise 2.1?

To act as the control

Disease-causing

Pathogen

When a microbe benefits their host

Mutualism

When the microbe benefits and has no significant effect on their host

Commensal

Strains that are capable of producing a disease state if introduced into a suitable part of the body (even includes some mutualistic/commensal strains)

Opportunistic

Any area where a microbe resides and serves as a potential source of infection. This also includes sites outside of the host organism.

Reservoir

Capsule

Primary stain- Congo red (stains the background) Counter stain- Maneval’s stain (stains the cells) Ex: *Bacillus anthracis*

Endospore: Central

endospore is in the middle of the cell

Endospore: Terminal

endospore is at the end of the cell

Endospore: Subterminal

endospore is between the end and middle of the cell

How to determine whether an endospore is spherical or elliptical

An endospore that is circular = spherical An endospore that is oval = elliptical

Endospore

Primary stain: Malachite green Counterstain: Safranin Ex: *Geobacillus*

2 types of flagella to identify

amphitrichous and peritrichous

Amphitrichous flagella

flagella at both ends of the cell Ex: *Spirillum volutans*

Peritichous flagella

flagella surrounding the entirety of the cell Ex: *Proteus vulgaris*

What is the primary stain for flagella?

Ryu stain

Cell morphology- shape

Coccus: spheres Bacillus: rods Spirillum: spirals

Cell morphology- arrangement

Diplo- Strepto- Tetra- Staphylo-

Diplo-

pairs of either cocci or bacilli

Strepto-

chains of either cocci or bacilli

Tetrads-

cocci in a group of 4

Staphylo-

cocci in a cluster-looking shape (resembles grapes)

Describe a basic dye

- Positive ion - Attracted to the negative charges on most bacterial cells

What is the purpose of heat fixing?

It attaches bacteria to the slide and kills it

Axenic

pure- not contaminated or is a single species

This is a plate that is the control- is it axenic?

This is a plate, one colony grew- is it axenic?

Yes

Aseptic

free of contamination

What are the three main types of solid media?

Petri plates, slant tubes, and deep tubes

Describe how to prepare a smear:

-Label the slide and draw a circle on the bottom of the slide -Place a small drop of water on the slide -Collect the sample and smear it over the slide -Let the sample air dry -Wave the slide over the fire 2-3 times (heat fix) -It's now ready to be stained

What appearance will a broth have if sterile? contaminated

Contaminated = turbulent (cloudy) Sterile = clear *The more turbid a culture, the greater the bacterial population

What appearance will a broth have if sterile? contaminated

Contaminated = turbulent (cloudy) Sterile = clear *The more turbid a culture, the greater the bacterial population

What appearance will a broth have if sterile? contaminated

Contaminated = turbulent (cloudy) Sterile = clear *The more turbid a culture, the greater the bacterial population

Define colony:

A visible mass of microbial cells arising from a single microbial species

What is the goal in a streak plate?

To produce isolated colonies

Describe the steps in a gram-stain

1. Flood slide with crystal violet (1 min) 2. Rinse 3. Iodine (1 min) 4. Rinse 5. Drip alcohol for 10-30 secs 6. Safranin 7. Rinse 8. Dry with bibulous paper

Primary stain

stains all cells purple; crystal violet

Mordant

intensifies the color of the primary stain; iodine

Decolorizer

removes the purple color from only the gram-negative bacteria; alcohol

Counterstain

Turns the colorless gram-negative bacteria pink; safranin

Gram-positive color

purple

Gram-negative color

pink

Failure to add the iodine in a gram stain

All bacteria may appear gram-negative

Failure to apply the decolorizer in a gram stain

All bacteria may appear gram-positive (all stained purple)

Failure to apply the safranin in a gram stain

Only the purple gram-positive bacteria would be seen

Reversal of crystal violet and safranin stains

Both G+ and G- would be purple

If you saw large, eukaryotic cells in the preparation made from your gumline, they were most likely your own epithelial cells. Are you gram-positive or gram-negative?

Gram-negative (most eukaryotic cells are G-)