Lab 1 Flashcards
What will a slant look like if it’s sterile?
Contaminated?
Sterile = no growth on the surface
Contaminated = growth on surface
Provides a sturdy flat surface to support/steady the microscope
Base
Located in the base. The light from the lamp passes directly upward through the microscope
Substage light
Located on the base or arm. This dial allows you to adjust the intensity of the light passing through the specimen
Light control
The platform that the slide rests on while being viewed
Stage
Holds the slide in position for viewing and has two adjustable knobs that control the precise movement of the slide
Mechanical stage
Small non-magnifying lens located beneath the stage that concentrates the light on the specimen
Condenser
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
Allows you to make large adjustments to the height of the stage to initially focus the specimen
Coarse adjustment knob
Used for precise focusing once the initial coarse focusing has been completed
Fine adjustment knob
Attaches to the nosepiece to support the objective lens system. Also provides attachment of the eyepieces which house the ocular lens.
Head
Vertical portion of the microscope. Connects the base and the head.
Arm
Rotating mechanism connected to the head. Generally carries four objective lenses.
Nosepiece
Attached to the nosepiece
Objective lenses
4 objective lenses:
Scanning (4x)
Low-power (10x)
High-power (40x)
Oil immersion (100x)
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
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
Order of threads
Top- red
Middle- blue
Bottom- yellow
Explain what the letter E looked like microscopically
The e flips upside down and backwards when viewed on a microscope
Total magnification for each objective lens
Scanning (4x) = 40x
Low-power (10x) = 100x
High-power (40x) = 400x
Oil immersion (100x) = 1000x
Define resolution
The clarity of an image
Define limit of resolution
The actual measurement of how far apart 2 points must be for the microscope to view them as separate
As the limit of resolution is made smaller, the resolution
improves
Colony Morphology- shape
circular
rhizoid
irregular
filamentous
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?
- Cover any culture spills with paper towels.
- Soak the towels immediately with disinfectant and allow them to stand for 20 minutes.
- Report the spill to your instructor.
- 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?
No
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
- Flood slide with crystal violet (1 min)
- Rinse
- Iodine (1 min)
- Rinse
- Drip alcohol for 10-30 secs
- Safranin
- Rinse
- 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-)
