Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
191 Cards in this Set
- Front
- Back
|
What occurs when light passes through 2 materials with different refractive indexes
|
it bends
|
|
|
What is numberical aperture?
|
The extent that light is concentrated by condenser and collected by objective
|
|
|
Why do you need immersion oil when you use 100x objective lens
|
Without oil, you can lose many light rays: with oil, you get more light to the eyes
|
|
|
Par Focal
|
When one lens is in focus, all are in range
|
|
|
What may occur when light hits an object?
|
reflection, refraction, transmission, absorption
|
|
|
What is refractive index?
|
measures how light fast light passes through
|
|
|
What does a dark field microscope do?
|
it sharply increases contrast between specimen: allow to see organism without staining
|
|
|
What occurs in a dark field microscope?
|
Condenser is modified so that light cannot enter objective directly (focuses light) and the only light that is deflected or scattered from the speciment enters the objective lens
|
|
|
Phase Contrast Microscope
|
A special optical device that is used to enhance the contrasts between the specimens and the background
|
|
|
Advantage of a phase contrast microscope
|
allows you to see specimen better
|
|
|
Advantage of dark screen microscope
|
Some organisms don’t stain easily and so this helps you to see it, and you can see the organism while alive
|
|
|
What does the diaphragm do
|
adjusts light for the lens
|
|
|
Scan power lens
|
4x and red
|
|
|
Low power lens
|
10x and yellow
|
|
|
high power lens
|
40x and blue
|
|
|
Oil lens
|
100x and white
|
|
|
Which is better: higher or lower resolution?
|
lower
|
|
|
For smaller, RP, what wavelength do you want?
|
shorter
|
|
|
For smaller RP what NA do you want
|
longer
|
|
|
What light gives the best resolving power for NA?
|
purple
|
|
|
Has flagella growing all over
|
proteus vulgaris
|
|
|
Culture medium
|
solution that contains nutrients to support growth of mos
|
|
|
3 types of medium
|
solid, semisolid, liquid
|
|
|
Liquid broth
|
can grow and use quickly; can't store because it makes toxic waste
|
|
|
Semisolid medium
|
Add with a solidifying agent like agar < 1%
|
|
|
Solid medium
|
Add with solidifying agent like agar >1.5%
|
|
|
Why agar and not gelatin?
|
agar is seaweed extract; Gelatin cant be used, because it’s animal protein; many organisms degrade and digest it
|
|
|
Agar turns solid
|
40 degrees C
|
|
|
Liquid
|
100 degrees C
|
|
|
What is a cluster or cells that originate from the multiplication of one single cell
|
colony
|
|
|
What are mos that are transferred from original culture to fresh medium
|
subculture
|
|
|
Gram + bacteria
|
Staphylococcus aureus, bacillus subtilis, micrococcus luteus, enterococcus faecalis
|
|
|
Gram - bacteria
|
Enterobacter aerogenes, E. Coli, Chromobacterium violaceum, serratia marc scents
|
|
|
Incubate plates
|
37 degrees C
|
|
|
Transparent bacteria
|
look same as bg, clear
|
|
|
Translucent
|
like wax paper
|
|
|
Opaque
|
look like paper
|
|
|
Shape of Staph Aureus
|
Round, opaque
|
|
|
Enterobacter aerogenes
|
Irregular, translucent
|
|
|
Bacillus subtillis
|
opaque, dry, irregular
|
|
|
E. Coli
|
transparent, moist
|
|
|
Micrococcus luetus
|
Yellow, opaque
|
|
|
Chromobacterium violaceum
|
purple
|
|
|
Enterococcus faecalis
|
opaque
|
|
|
Serratia marcescens
|
translucent, red
|
|
|
most important stain for identification of unknown bacteria stain
|
gram stain
|
|
|
primary stain for a gram stain
|
crystal violet for 1 min
|
|
|
What does crystal violet turn purple?
|
G+ and G-
|
|
|
Mordant for gram stain
|
iodine
|
|
|
Crystal violet and iodine
|
increases affinity of dye to cell and cannot easily be washed out of peptidoglycan layer
|
|
|
Decolorizer for gram stain
|
95% ethanol for 15 seconds
|
|
|
What does decolorizer in gram stain do?
|
Dissolves the lipid in G- outer membrane CV-I is washed out through the thin peptidoglycan layer
|
|
|
Counterstain for gram stain
|
safranin for 1 min
|
|
|
Final colors after Gram stain
|
G+ purple and G- red
|
|
|
nutrient material prepared for the growth of mos in a lab
|
culture media
|
|
|
Agar slant
|
To grow and maintain mos after growth for short term
|
|
|
Agar plate used for
|
Large growth surface for streaking or spreading of the mos to yield individual colonies
|
|
|
Chemically defined media
|
The exact chemical compositions are known
|
|
|
Complex medium
|
The medium contains ingredients that are not chemically defined such as beef extract and brain heart infusion or yeast extract
|
|
|
Which does organisms grow best?
|
complex medium
|
|
|
What is the medium that contains special ingredients that allow certain groups of mos to grow
|
Enriched medium
|
|
|
medium containing selective agents, which inhibit growth of undesirable mos while allowing the desired mos to grow
|
Selective medium
|
|
|
When is a selective medium useful?
|
For isolating a low number of target mos from a high number of background microbes
|
|
|
Example of selective agent
|
Phenyl tethyl alcohol agar that inhibits G- bacteria or salt to allow staph aureus to grow
|
|
|
What is a medium containing differential agents that allow differentiation of desired mos from others
|
Differential
|
|
|
Example of a differential agent
|
Blood/Blood agar
|
|
|
Alpha hemloysis
|
Partial clearing with the green zone
|
|
|
Complete lysis with clear zone
|
beta hemolysis
|
|
|
No lysis
|
Gamma hemolysis
|
|
|
What does a mannitol salt agar do
|
Selective and differential
|
|
|
What is MSA’s selective property
|
Has 7.5% NaCl to allow staphylococcus spp to grow and inhibits non salt tolerant mos
|
|
|
What is MSA’s differential agent
|
Mannitol (the only CH2O in the medium) and it has phenol red as a pH indicator and Mannitol to detect acid
|
|
|
What does pH color of MSA do?
|
Below 6.8 is yellow/ neutral is orange/ basic is deep pink
|
|
|
What color does mannitol turn acid?
|
yellow
|
|
|
MacConkey Agar
|
Selective and Differential
|
|
|
What does hot pink in MacConkey Agar mean?
|
it broke down lactose and made acid
|
|
|
MacConkey selective
|
Has bile salts to inhibit nonenteric mos and crystal violet to inhibit G+ bacteria (so only G- intestinal mos can grow)
|
|
|
MacConkeys differential properties
|
Lactose (the only CH2O) and below 6.8 pH turns hot pink and above 6.8 there is no color
|
|
|
4 reasons the cell may be discolored after staining
|
Over-decolorization (G+ appears red): Under-decolorization (G- appears purple): Thick smear (cannot be decolorized properly) and Aged culture (G+ cell wall deteriorates and turns red)
|
|
|
What is semisolid agar used for?
|
motility test
|
|
|
What does acid stain do?
|
Chromogen- + ion+ (Na+, K+, CA++)
|
|
|
What does basic stain do?
|
Chromogen+ + ion- (Cl-, SO4-)
|
|
|
WHat does chromogen of acid dye do?
|
Bind to positively charged surface
|
|
|
What does chromogen of basic dye do?
|
bind to negatively charged surface
|
|
|
Simple stain?
|
one stain
|
|
|
Differential stain
|
2 stains
|
|
|
What do you do for group separation?
|
gram stain, acid fast stain
|
|
|
Showing structures?
|
spore stain, capsule stain
|
|
|
Smear for broth
|
1-2 loopful on slide
|
|
|
Smear for solid?
|
1 loop of tap water and one loop of bacteria into water and spread to thin smear
|
|
|
Heat fixation
|
pass through the flame 3 times, use heat to coagulate the cells protein so it sticks to the slide tightly
|
|
|
How do you prepare a slide?
|
clean slides, label, smear prep, air dry, heat fix
|
|
|
Simple stain
|
Dye for 1 min, rinse with tap water, blot dry, observe bacteria
|
|
|
Colony
|
a population of organisms derived from one single cell
|
|
|
T Streak
|
Glide loosely on the surface in first area continuously, overlapping, then the second section, go back only 3 times with a sterile loop, then the last section, go back only 3 times with sterile loop
|
|
|
What do you use for simple stain
|
basic dye
|
|
|
For negative stain
|
acid dye
|
|
|
What do you do for a negative stain?
|
stain everything except what you want to see
|
|
|
What does a spectrophotometer measure
|
turbidity
|
|
|
What is the bacterial number in the tube estimated based on
|
tubidity
|
|
|
What does a spectrophotometer do?
|
As the light passes through the tube, some of the light rays are bounced back by cell particles. The remaining passes through and it can be read by a photometer
|
|
|
What is the density of a cell suspension expressed as
|
absorbance or optical density
|
|
|
What is optical density directly proportional to
|
concentration of cells
|
|
|
Generation Time
|
GT= t log2/ log P2- Log P1
|
|
|
Acid fast cell wall
|
High lipid content in cell wall/ hydrophobic/ difficult for stain, water, and nutrients to penetrate/ slow growing, resist drying, resistant staining and decolorizing
|
|
|
What makes an acid fast cell wall hydrophobic
|
waxy coat
|
|
|
What are 2 significant pathogens of acid fast
|
Mycobacterium tuberculoses (causes TB) and M. leprae (causes leprosy)
|
|
|
Screening method for TB
|
acid fast stain
|
|
|
What is the primary stain for Kinyoun’s method?
|
Kinyoun’s cabol fuchsin for at least 10 minutes and it will turn acid fast and non acid fast pink
|
|
|
Decolorizer for Kinyoun's method
|
Acid alcohol for 10 sec and it will make acid fast pink and non acid fast colorless
|
|
|
What is Kinyoun's method used for?
|
acid fast stain
|
|
|
Kinyoun's Counter stain
|
Methylene blue for 2 min and it will make acid fast pink and non acid fast blue
|
|
|
After Kinyoun's method, what color will acid fast be? and non acid fast?
|
pink and blue
|
|
|
What is the primary stain in Bartholomew mittwers method
|
Malachite green for 20 minutes and it will turn the vegetative cell green and the spore green
|
|
|
What is Bartholomew Mittwers method used for?
|
endospore stain
|
|
|
Mordant in Batholomew Mittwers method?
|
none
|
|
|
What will occur when you rinse off the malachite green
|
Vegetative cell colorless and spore green
|
|
|
Counterstain for Bartholomew Mittwers method
|
Safranin for 1 minute and the vegetative cell will be red and spore green
|
|
|
What are 2 genera bacteria that form endospores?
|
B. subtilis and Clostridium spoogenes
|
|
|
What is a substrate that allows bacterial waste?
|
Mannitol (acid) carbs
|
|
|
What makes an acid fast cell wall hydrophobic
|
waxy coat
|
|
|
What are 2 significant pathogens of acid fast
|
Mycobacterium tuberculoses (causes TB) and M. leprae (causes leprosy)
|
|
|
Screening method for TB
|
acid fast stain
|
|
|
What is the primary stain for Kinyoun’s method?
|
Kinyoun’s cabol fuchsin for at least 10 minutes and it will turn acid fast and non acid fast pink
|
|
|
Decolorizer for Kinyoun's method
|
Acid alcohol for 10 sec and it will make acid fast pink and non acid fast colorless
|
|
|
What is Kinyoun's method used for?
|
acid fast stain
|
|
|
Kinyoun's Counter stain
|
Methylene blue for 2 min and it will make acid fast pink and non acid fast blue
|
|
|
After Kinyoun's method, what color will acid fast be? and non acid fast?
|
pink and blue
|
|
|
What is the primary stain in Bartholomew mittwers method
|
Malachite green for 20 minutes and it will turn the vegetative cell green and the spore green
|
|
|
What is Bartholomew Mittwers method used for?
|
endospore stain
|
|
|
Mordant in Batholomew Mittwers method?
|
none
|
|
|
What will occur when you rinse off the malachite green
|
Vegetative cell colorless and spore green
|
|
|
Counterstain for Bartholomew Mittwers method
|
Safranin for 1 minute and the vegetative cell will be red and spore green
|
|
|
What are 2 genera bacteria that form endospores?
|
B. subtilis and Clostridium spoogenes
|
|
|
What is a substrate that allows bacterial waste?
|
Mannitol (acid) carbs
|
|
|
What is the purpose of aseptic technique?
|
to avoid contamination of the culture or environment
|
|
|
What is the purpose of isolation of pure culture?
|
to separate mos in mixed culture and obtain pure culture
|
|
|
What may be used to describe shape of the colony?
|
circular, irregular, rhizoid
|
|
|
WHat may be used to describe margin of the colony?
|
entire, lobate, undulate, filamentous, serrate
|
|
|
What may be used to describe elevation?
|
flat, raised, convex, umbonate
|
|
|
What may be used to describe optical characteristics?
|
transparent, translucent, opaque
|
|
|
What may be used to describe texture?
|
smooth, shiny, dull, rough, wrinkley, granular, mucoid
|
|
|
What is the most important stain for identification of unknown bacteria?
|
gram stain
|
|
|
Describe the items used in gram stain:
|
primary stain- crystal violet (1 min), mordant- iodine (1 min), decolorizer- 95% ethanol (15 sec), and counterstain- safranin (1 min)
|
|
|
What is the primary stain in gram stain procedure?
|
crystal violet 1 min
|
|
|
WHat is the mordant in gram stain?
|
iodine 1 min
|
|
|
What does CVI do?
|
cannot be easily washed out from thick peptidoglycan and increases affinity of dye to cell wall
|
|
|
What is the decolorizer in the gram stain?
|
95% ethanol for 15 sec
|
|
|
What is the counterstain in gram stain?
|
safranin
|
|
|
What are the 4 most common errors in gram stain?
|
over decolorization, under decolorization, thick smear, aged culture
|
|
|
What will a gram stain look like if it was over decolorized?
|
G+ appears red
|
|
|
What will the gram stain look like if it was under decolorized?
|
G- appears purple
|
|
|
What if the smear was too thick for a gram stain?
|
cannot be decolorized properly
|
|
|
What if the culture aged?
|
G+ cell wall deteriorates and appears red
|
|
|
What is solid?
|
broth plus solidifying agent
|
|
|
What is semisolid?
|
broth plus a little solidifying agent
|
|
|
What are 2 types of solid?
|
agar slant and agar plate
|
|
|
What is semisolid?
|
semisolid agar deep for motility test
|
|
|
What is the most commonly used solidifying agent?
|
agar
|
|
|
What is a complex polysaccharide made from seaweeds?
|
agar
|
|
|
WHat are examples of chemically defined medium?
|
glucose broth, glucose salt medium
|
|
|
What are examples of complex medium?
|
beef extra, brain heart infusion, nutrient broth, yeast extract broth
|
|
|
What are examples of enriched medium?
|
blood agar, orange serum agar
|
|
|
What are examples of selective mediums?
|
phenyl ethyl alcohol agar that inhibits G-
|
|
|
What is a differential agent?
|
blood
|
|
|
What can a spectrophotometer detect?
|
bacteria in a broth culture containing >10 (to the 6th) cells/mL
|
|
|
What is GT?
|
time needed for absorbance to double
|
|
|
What is an organism that requires extra nutrients?
|
fastidious
|
|
|
What do you calibrate the machine at?
|
with different broths/ colored and absorb light
|
|
|
WHat does absorbance coreespond to?
|
vial amount
|
|
|
If there is more transmission, there is less?
|
absorbance
|
|
|
If there is more absorbance, there is less?
|
transmission
|
|
|
What is bacterial cells?
|
negative charged and basic dye
|
|
|
What shifts rays into misalignment?
|
phase contrast microscope
|
|
|
What cells are colorless before counterstain?
|
G-
|
|
|
What do acid fast appear when properly stained?
|
blue
|
|
|
What does mannitol inhibit?
|
G-
|
|
|
WHat objective lens has smallest working distance?
|
100x or oil immersion lens
|
|
|
WHat is an enrichment agent?
|
blood in blood agar
|
|
|
What is an example of 10 fold dilution?
|
0.1 mL into 0.9 mL
|
|
|
What are the advantages of dark field and phase contrast microscopes?
|
unstained organisms
|
|
|
What is not a physical requirement for growth?
|
source of Carbon
|
|
|
What is not chemically defined?
|
yeast broth
|
|
|
WHat is the reason to heat fix?
|
affinity and adhesion
|
|
|
Why do you place agar plates upside down?
|
so moisture doesn't affect the experimental colonies
|
|
|
Why do we use immersion oil?
|
to allow light of the same optical density
|
|
|
WHat is MAC
|
a differential agent and pH indicator
|
|
|
If G+ appears red after a gram stain, you probably?
|
overdecolorized
|
|
|
WHat microscope has the highest resolving power?
|
electron microscope
|
|
|
WHat is RP dependent on?
|
amt. of wavelength: the shorter the wavelength, the higher the RP
|
|
|
WHy should you use phase contrast over bright field?
|
gives better contrast between the specimen and background
|
