Lab 1 & Lab 2A- Study Quiz Flashcards
Adjust the ocular lenses distance to accommodate your individual ____ _____.
interpupillary distance
After ______ (last step), as a result of this dilution technique, individual colonies of microbes can be obtained.
incubation
As the magnification of the objective lens increases, so does the _____ ______.
numerical aperture
Endospores are most commonly found in …
Bacillus sp. & Clostridium sp
low G+ C Gram positive bacteria
2 correct responses:
In acid fast bacterial staining procedures…..
=It depends on mycolic acid (It reinforces the cell wall and makes the bacterium resistant to certain chemicals and dyes)
=The Kinyoun stain can be used to stain Nocardia species and Crytosporidia
culture/ cultured means
grown / growing
Each individual colony represents the descendants of a ___ ___.
Single Cell
How do you find the magnification?
Ocular lens X objective lens
How do you refocus the new image after changing to higher magnification?
Use the fine adjustment knob
If you are determining a bacteria morphology, what are you going to focus on?
shape, size, & arrangement
If your CONTROL test tube is CLOUDY, what does this mean?
You did not correctly use the aseptic techniques. It should remain clear. It is the controlled tube, so it shouldn’t grow anything.
In numerical aperture (n* sin a), (sin a) is ___ of the ___ ___ of the image forming rays of the objective lens.
1/2, acceptance angle
In numerical aperture (n * sin a), the (n) is ?
The refractive index or index of refraction
Refractive index
measure of the bending/ “refraction” of a ray of light when passing from one medium into another.
In the Gram Stain, Iodine is used as the____?
Mordant
Mordant
Substance used to set or stabilize stains or dyes.
Example: Iodine acts like a trapping agent that complexes with the crystal violet, make the crystal violet-iodine complex clump and stay contained in thick layers of peptidoglycan in cell walls.
List the basics of aseptic techniques that are used in lab…
Autoclave or steam sterilization of all equipment and media.
Flame sterilization of wire loops and needles which are used to transfer bacteria from one growth condition to another.
Flaming the mouth of test tubes and other containers to establish hot air convection out of the container, to reduce the chance of microbes entering the tube by air flow.
Numerical Aperture
Related to the angles of light which are collected by lens.
—> NA= “n sin a” where (n )is the refractive index and (a) is half the acceptance angle of the image forming rays of the objective lens.
Resolution is dependent on the _A__ of light used (in um),
the _B__ quality, and the refraction and _C__ of light as it passes through the object and air
A. wavelength
B. lens
C. reflection
The Bunsen burner should be adjusted so that you can see __A_ flames.
The dark blue flame is in the __B_ of the flame.
The light blue flame is at the __C_ of the flame.
A. 2
B. center
C. top
The direction of stage movement is ______ to that of the field movement.
Opposite
The standard method of obtaining a “PURE CULTURE” is the
___ ____ method on agar.
Streak-plate
The ____ is below the stage on a microscope.
Condenser
True or False: The resolution of a light microscope is the smallest distance between two adjacent points capable of being distinguished on a slide.
True
Inoculated
introduced
How many objective lens are on the microscope in our lab?
List their magnification
4 objective lens 4x=40x 10x=100x 40x=400x 100x=1000x
Pathology of bacteria means…
ability to cause disease
What is the purpose of the CONDENSER
Focus light onto the specimen
What is a “PURE CULTURE”?
Uncontaminated culture
What is differential stain procedure?
stain procedure consists of at least two different dyes which highlight a biochemical reaction within the cell. It shows more than just simple cell structures.
What is resolution?
the smallest distance two closely adjacent objects can be clearly distinguished with the lens system that is set up
What are the two properties that determine image quality?
Magnification / Resolution
What is simple stain procedure?
consists of only one dye to increase cell contrast from a slide background. It shows simple cell structure.
What is the process of growing pure cultures and is essential for proper characterization of a bacterium?
aseptic (sterile) technique
_______ has to be performed without adding other microbes or contaminates.
inoculation
What is the formula used to calculate resolution? What does (λ) mean? What does NA stand for?
Resolution = λ / (2xNA) where λ = wavelength of light in μm (microns) NA = numerical aperture (+0)
Where is the numerical aperture found?
Numerical aperture is etched onto the objective lens next to that lens’ magnification.
The smallest resolution of the light microscope can be obtained with:
The shortest wavelength of visible light used and an objective lens with the maximum numerical aperture
What is the total magnification of a slide field if you are visualizing that field with the 40X objective lens?
400X magnification.
How do you find total magnification?
ocular lens (10x) X objective lens (4x, 10x,40x,100x)
What is the correct order of reagent use when performing a Gram stain?
crystal violet, iodine solution, acetone alcohol, safranin
Basic stains have a positively charge auxochrome? T or F
TRUE
Negative stains are attracted to glass. T or F
True
Positive stains are attracted to cell contents. T or F
True
Nigrosin is a basic stain. T or F
False- It is an acidic stain
Methylene blue is a basic stain. T or F
True
What color will a gram negative organism be if the decolorizing step is left out while performing a gram stain on it?
Purple
Choose the INCORRECT response:
A. is a virulence factor
B. its size is not determined by its growth medium
C. can be composed of polysaccharides or polypeptides
D. is genetically determined
B. its size is not determined by its growth medium
In Acid Fast Bacterial staining procedures: The Kinyoun stain can be used to stain _______ and ______.
Nocardia species and Cryptosporidia
Acid Fast Bacterial staining procedures depend on______?
depends on mycolic acid
T or F: There are several species of Mycobacterium that are of human clinical significance. The species that is most significant is Mycobacterium leprae.
False- Mycobacterium tuberculosis is a species of pathogenic bacteria that is the causative agent of tuberculosis.
First discovered by Robert Koch, M. tuberculosis has an unusual, waxy coating on its cell surface primarily due to the presence of mycolic acid
Choose the CORRECT response(s):
Endospores______
A. are most commonly found in Bacillus sp. and Clostridium sp.
B. are never found in gram negative bacilli
C. are mostly found in low G+C Gram positive bacteria
D. never found in gram positive cocci
A & C
T or F: Compound light microscope use halogen-quartz lamp light sources?
True
T or F: A light micrscope allows us toview objects that are as small as 0,2 um (microns/micrometers).
True
What is MAGNIFICATION?
Size of the image relative to the actual size of the object viewed
What is resolution?
The smallest distance two closely adjacent objects can be clearly distinguished with the lens system that is set up.
If you are using oil immersion lens what is the image magnification?
1000x
Numerical aperture= (n) x (sin a)
True of false
True
Where is the numerical aperture (NA) located?
Etched next to the magnification of the objective lens used
Adjust the ocular lenses distance to accommodate your individual _________ _________.
interpupillary distance
Always rotate the objective lens from highest to lowest magnification?
True or False
False- You rotate from lowest to highest
When going from 40x=400x to oil immersion, you add a drop of oil just before rotating the 100x= 1000x lens into place, then you focus with the (FINE) adjustment knob.
True or False
True
Most bacterial observations are best viewed with the condenser at it’s (LOWEST or HIGHEST) point?
Highest
What is located on top of the condenser?
What does it control?
Iris Diaphragm- controls the amount of light illuminating the specimen
If you are viewing at low magnifications the amount of light for best observations should be ( HIGH or LOW)
Low
Do high magnifications need more light or less light?
What do you adjust to control the light amount?
More light can be added by opening the iris diaphragm
The amount of light can be adjusted by the iris diaphragm and the
___/___ rheostat.
On/OFF
T or F: Always use the coarse adjustment knob first?
Where is the coarse adjustment knob located?
True, The coarse adjustment knob is the bigger of the two knobs and is located closest to the arm of the microscope
The only focus knob that is used for 1000x is _____.
oil immersion
Fine focus knob- smaller of the two
True or False
Resolution = lambda / (2NA)
True
In formula Resolution = λ / (2NA) Lambda (λ) is the ____A___ of light and NA is the objective lens __B___.
A wavelength
B. numerical aperture
Calculate the resolution of a magnification system if you are using light at a wavelength of 5x10^-1 µm and the 4X objective lens with a NA = 10^-1
Resolution = lambda / (2NA)
= 5 x 10^-1 µm / 2 x 10^-1
= 2.5 x 10^0 µm
= 2.5 µm
Which response(s) is correct:
Bacteria are very small in the range of .5-1 um.
You need a magnification system to accommodate this:
A. a higher magnification system
B. a smaller wavelength of light
C. Both
D. All of the above
All of the above
As the magnification of the objective lens increases, so does the _____ ______.
Numerical Aperture (NA)
Inoculate mean:
Introduced
What is a culture?
“the cultivation of microorganisms” / to grow
If something is cultured in the laboratory it is GROWN there for test studies.
To determine a bacteria’s MORPHOLOGY, what is your main focus?
Shape, Size, Arrangement
Pathology is ________
a branch of medical science primarily concerning the cause, origin and nature of disease.
What is a pathogen?
a bacterium, virus, or other microorganism that can cause disease
Bacteria are ___A__ and ___B__ in the laboratory for studies to determine their morphology and pathology.
A. Inoculated
B. Cultured
The ________ (introduction) has to be performed without adding other microbes or contaminants
Inoculation
What is the process of growing pure cultures and is essential for proper characterization of a bacterium?
Aseptic (sterile) techniques
TRUE OR FALSE:
In order to determine the cause of a disease the microbe must be separated from the mixture and cultured as a pure culture.
True
What is the standard method of obtaining a “pure culture” on agar?
Streak Plate Method
True or False: The streak plate method is an example of a solid dilution technique.
True
T or F: In microbiology, streaking is a technique used to isolate a pure strain from a single species of microorganism, often bacteria.
True
What is a dilution technique?
dilution technique- bacteria are obtained from a mixed culture with a sterile loop and diluted within three sectors on a petri dish containing appropriate growth medium. After incubation, as a result of this dilution technique, individual colonies of microbes can be obtained.
After _________ (last step), as a result of dilution technique, individual colonies of microbes can be obtained.
Incubation
Each individual colony represents the descendants of a \_\_\_\_\_\_ A. 2 cells B. 1 single cell C. 4+ cells D. virus
B. a single cell
True or False: 1 million (10^6) bacteria are necessary to be VISIBLE to the naked eye.
True
True or False: By inoculating the individual colony with a sterile loop onto a fresh agar surface, a pure culture may be obtained.
True
T or F: Your aseptic technique was correctly done if you grew microorganisms in your CONTROLLED test tube.
False, the purpose of the controlled test tube in lab was to prove that you understand the steps of the aseptic technique. The main goal is to NOT have bacteria growth. If you didn’t grow bacteria then consider yourself ASEPTIC TECHNIQUE TOP STAR!
True or False: The hottest area on the Bunsen burner flame is the top portion of the light blue flame.
True
The incubator is set to \_\_\_\_ degree Celsius. A. 32 B. 33 C. 35 D. 37
D. 37 degrees Celsius
T/F: If the petri dish is not in use it should be kept UPSIDE DOWN (media on top) to prevent dust from introducing microbes to the media and to prevent condensed water from falling on the media from the lid.
True
True or False: The streak plate technique is the most popular method for isolating specific bacteria from a sample containing a mixture of microorganisms
True
Basic stains have a positively charge auxochrome? T or F
True
Negative stains are attracted to glass: True or False
True
T or F: Positive stains are attracted to cell contents.
True
T or F: Nigrosin is a basic stain
False: it is an acidic stain
True or False
Methylene Blue is a basic stain.
True
What is a simple stain procedure?
A. consists of only one dye to increase cell contrast from a slide background. It shows simple cell structure.
B. consists of at least two different dyes which highlight a biochemical reaction within the cell. It shows more than just simple cell structures.
C. consist of 2 dyes and using the “cold method”
A.consists of only one dye to increase cell contrast from a slide background. It shows simple cell structure.
What is a differential stain procedure?
A) stain procedure consists of only one dye to increase cell contrast from a slide background. Shows simple cell structure
B) stain procedure consists of at least two different dyes which highlight a biochemical reaction w/in the cell. Shows more than just simple cell structures.
B) stain procedure consists of at least two different dyes which highlight a biochemical reaction w/in the cell. Shows more than just simple cell structures.
If your controlled test tube is cloudy, what does that mean?
You did not flame the mouth of the test tube You did not sterilize your loop long enough,You did not follow aseptic technique correctly
True or False: Make sure you blow on your loop to help it cool faster.
False!
How do you label your specimen?
Initials, Date, Name of Bacteria
What does NB and NA mean in micro-lab?
NB- Nutrient broth
NA- Nutrient agar
Steps when transferring Broth to Broth
- label specimen
- Flame loop/cool
- Pick up tube with left hand & remove cap by curling small and ring finger of your right hand around the cap
- Flame neck of tube & remove loop full of culture & flame tube again (briefly), place cap back on.
- Now for the inoculation: remove cap from your test tube, flame mouth of tube & insert loop containing the culture into tube then remove. Flame mouth of tube again, replace cap.
- Hold Loop at angle to sterilize it in the flame again, until loop is red THEN incubate at 37* C.
Steps when transferring Broth to Plate:
- obtain NA plate and label w/ initials, date, specimen
- Flame loop & cool
- Pick up bacteria tube, remove cap & flame mouth
- insert loop into bacteria culture & remove loop full of broth, flame mouth, replace cap
- Streak NA plate using the 3 streak method
- Once streaking method is completed, sterilize loop until red/cool
- Incubate plate, INVERTED, in 37*C.
Steps for Plate to Plate transfer:
- label the 2nd NA plate on the bottom w/ initials,date,specimen name “plate to plate”
- obtain stock plate of bacteria and place plate upside down on the bench near flame
- Flame loop & cool
- pick up plate of specimen, open lid & use sterile loo[ to remove one colony from plate. Place lid back quickly
- pick up NA plate, leave lid on table by flame & start 3-sector streak. Replacing lid AFTER EACH SECTOR HAS BEEN STREAKED. Sterilizing loop between each sector streaking.
6, Flame loop to sterilize it - Incubate plate, inverted, in 37*C
