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Microbiology 202 Quiz 1
ch. 1-10
113
Microbiology
Undergraduate 2
09/27/2015

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Term
resolution
Definition
the ability to see objects that are close together as multiple, distinct and separate objects
Term
resolving power
Definition
function of the wavelength go light that forms the image, along with certain characteristics if lenses
Term
magnification
Definition
relative enlargement of the specimen when seen through the microscope.
Term
what's the smallest wavelength that a light microscope can magnify to?
Definition
.2um
Term
What is the magnification of the eyepiece (ocular) of the microscope that we use in lab?
Definition
10x
Term
what are the 3 objective lens magnification?
Definition
(4) 40x, (10) 100x, (45) 450x, (100) 1000x
Term
as the capacity to magnify _______, the diameter of the lens usually ________.
Definition
increases, decreases
Term
what is done about the large about of light scattering at high magnifications?
Definition
we use immersion oil!
Term
working distance
Definition
distance between lens and specimen.
Term
working distance _______ with increasing magnification.
Definition
decreases
Term
depth of field
Definition
the distance between the highest point and the lowest point of a 3D object that is in sharp focus.
Term
depth of field _______ with increasing magnification.
Definition
decreases
Term
at lower magnifications, the depth of field is ________.
Definition
deeper.
Term
parfocal
Definition
different lenses with different focal lengths are set in the rotating nose piece so that when you rotate them, the image should still be clear.
Term
iris diaphragm
Definition
controls the amount of light passing through the slide....at a higher magnification the diameter of light is increased
Term
condenser
Definition
focuses light coming up from the lamp below
Term
protozoan, fungal, plant, and animal cells are all what?
Definition
eukaryotic cells
Term
difference between broths and agar?
Definition
broths are liquid culture...agars are solidified.
Term
Frannie Hesse
Definition
wife of Walther Hesse who created agar media
Term
agar will not melt until what temperature?
Definition
90 degrees
Term
turbid
Definition
evenly suspended in solution to produce uniform cloudiness
Term
flocculent
Definition
cells are floating in visible, separated clumps called floc
Term
pellicle
Definition
cells form thick layer on the top of the broth, often due to high lipid content
Term
What is an appropriate storage temperature for 2-3 months?
Definition
0-4 degrees, refridgeration...good for anaerobes
Term
What is an appropriate storage temperature for long term?
Definition
Freezing -20 to -100 degrees
Term
Lyophilizing
Definition
freeze drying..removes H20 and cold to stop metabolism
Term
what can you do to ensure life during storage for facultative aerobes?
Definition
stab tubes
Term
What is an appropriate storage temperature for 2-3 months?
Definition
0-4 degrees, refridgeration...good for anaerobes
Term
What is an appropriate storage temperature for long term?
Definition
Freezing -20 to -100 degrees
Term
Lyophilizing
Definition
freeze drying..removes H20 and cold to stop metabolism
Term
what can you do to ensure life during storage for facultative aerobes?
Definition
stab tubes
Term
advantages of pour plating
Definition
..produces more isolated colonies
Term
disadvantages of pour plating
Definition
more time consuming
Term
bacteriostasis
Definition
cells are alive but inactive
Term
what is the best method of storage for strict aerobes? What about facultative anaerobes?
Definition
refrigeration on agar slants--stab tubes.
Term
simple stain
Definition
solely improves contrast with one stain
Term
differential stains
Definition
Gram staining, acid fast stain
Term
structural stains
Definition
spore and flagellum strains
Term
chromogen
Definition
the colored ion in the simple stain
Term
chromophore
Definition
part of a molecule that absorbs nd reflects particular wavelengths of light
Term
direct stains
Definition
chromogen is positively charged
Term
indirect stains
Definition
also called acid stains "negatively charged"
Term
pros of indirect staining
Definition
not heated==> so there is no distortions...cells with want coatings reject the direct staining
Term
Eosin and Nigrosin are examples of what?
Definition
indirect staining.
Term
which pH do direct and indirect stains work best at?
Definition
direct: high indirect: low
Term
strepto
Definition
arranged in chains
Term
staphylo
Definition
cells that form clusters
Term
strepto
Definition
arranged in chains
Term
staphylo
Definition
cells that form clusters
Term
what do gram positive cells have that gram negative cells do not have?
Definition
thick peptidoglycan wall
Term
what do gram negative bacteria have on the outside of their cells?
Definition
phospholipid envelope and small peptidoglycan layer
Term
when stained, gram positive cells are _______ in color.
Definition
purple
Term
when stained, gram negative cells are _______ in color.
Definition
pink/red
Term
what can lead to the decolorization of crystal violet from gram positive cells ?
Definition
over-colorization, age of the cells, acidity of the media. Media pH drops in time, so you should do it right away.
Term
The spore stain is an example of what kind of stain?
Definition
structural
Term
Which bacteria is known for causing food poisoning? How do they do that?
Definition
B. cereus--> they produce enterotoxins
Term
Which bacteria are STRICT anaerobes and are soil dwellers?
Definition
clostridium
Term
Which bacteria causes botulism--when seeds germinate under anaerobic condition?
Definition
C. botulinum
Term
Which bacteria can cause wound infection by gas gangrene and cause food poisoning/?
Definition
C. perfringens
Term
Which step comes first in the process of spore staining? Decolorizer or Counterstain?
Definition
decolorizer
Term
What does glucose satisfy?
Definition
chemical energy and carbon source
Term
what are peptones and tryptones examples of?
Definition
protein digests that have amino acids
Term
Complex media
Definition
if any of the said ingredients are undefined, then it is complex.
Term
Minimal agar is what type of media?
Definition
defined media
Term
How does autoclave raise the temperatures so high?
Definition
raising PSI until 15-20 and the temperature increases to 250 F.
Term
Ionizing Radiation
Definition
strip electrons from atoms, mutates DNA, and used to sterilize food and some plastic wear.
Term
Filtration
Definition
removes pathogens from air; used in place of autoclaving if something is heat sensitive.
Term
Which type of sterilization method is used to sterilize biohazard bags?
Definition
bunsen burner and large scale incineration
Term
ethylene oxide,
Definition
sterilizing gas to clean moisture sensitive equipment
Term
psychrophiles
Definition
cold loving microbes from -5 to 20 C. ..found in alpine and arctic soils
Term
psychotrophs
Definition
20 -30degrees
Term
mesophiles
Definition
25- 40degrees
Term
thermophiles
Definition
55 to 65
Term
hyperthermophiles
Definition
most have optional temperatures at 25-35, but can withstand temperatures above 100 for more than 10 minutes
Term
hypotonic environments
Definition
expanding cell due to higher concentration inside cell
Term
hypertonic environments
Definition
water flows out of the cell because there is more solute on the outside of the cell
Term
exoenzymes
Definition
enzymes that act on substrates on the outside of the cells.
Term
If you wanted to find a bacteria that produced exoenzymes, where would you look ?
Definition
the soil
Term
what's the difference between amylopectin and amylose?
Definition
amylose is tightly bound glucose molecules starch while amylopectin is loosely bound branching chains of glucose
Term
What do amylases do?
Definition
they are enzymes that are secreted from the cell that break down large poylmers of starch and transport them across the cell
Term
how can you tell if the cells produce amylase?
Definition
if there is a colorless zone or halo extending out from the microbial growth surrounded by the areas stained by blue-violet, this is a positive reaction.
Term
what is the purpose of the phenol red carbohydrates assays?
Definition
used to asses a given microorganism's ability to produce the intracellular enzymes needed to ferment mono-disaccharides. Does this through tracking pH changes
Term
using phenol red, from 5.3-6.3, the color of the liquid is ________?
Definition
yellow
Term
using phenol red, from 6.8-7.8, the color of the liquid is ________?
Definition
orange
Term
using phenol red, from 8.3 to 9.3, the color of the liquid is ________?
Definition
red
Term
what is a positive reaction for the test of fermentation?
Definition
broth has bright yellow color
Term
what is a negative reaction for the test of fermentation?
Definition
orange to red color
Term
What is an example of a false negative in the fermentation assay?
Definition
false negative can occur if the bacteria exhausted the supply of sugars by rapid fermentation, and then used amino acids as the primary source. This would generate NH3 and would raise the pH.
Term
What is the casein assay testing for?
Definition
secreted proteases
Term
what is the positive result for the casein reaction?
Definition
if there is a transparent zone, then proteases were secreted!
Term
what does the lysine debaroxylase assay test?
Definition
production of cadaverine and/CO2..detects removal of carboxyl group from lysine
Term
why is bromocresolpurple used instead of phenol red for the lysine decarboxylase assay?
Definition
it changes at a lower pH(more acidic)
Term
what is the positive assay result for lysine decarboxylase ?
Definition
purple color
Term
what is the negative assay result for lysine decarboxylase ?
Definition
yellow color
Term
Why can't see view viruses in this lab?
Definition
Because our microscopes only reach to .4 and .7um and cannot magnify or resolve to a typical virus size of .01 and .10.
Term
What is the relationship between resolution and wavelength?
Definition
r = (1/2) lambda
Term
What is the difference between "high resolution" and " high magnification"
Definition
high resolution- the distance between two objects that reveals them as separate objects is minimized. high magnification - the enlargement of the specimen when seen through the microscope is maximized.
Term
Besides using immersion oil, what makes using the 1000x magnification difficult?
Definition
1. depth of field is too shallow
2. shorter working distance
Term
What color is S. morescans?
Definition
red
Term
What two things could you do if your streak plating failed?
Definition
1. pour plating 2. wait longer for the sterile loop to cool
Term
Is E. coli gram positive or negative?
Definition
negative
Term
Is M. luteus gram positive or negative? Strucutre?
Definition
positive, tetrad, coccus
Term
Is B. megatherium gram positive or negative? What is its structure?
Definition
positive, strepto, chains
Term
This bacteria is diplo and cocci
Definition
e. coli
Term
What is the gram stain and structure of E. faecalis?
Definition
gram positive, streptobaccilus
Term
Why are gram positive cells purple?
Definition
they retain the purple color of crystal violet better in their peptidoglycan layer
Term
When B. megatherium cells are gram stained, the cells may have white colorless oval inside the cells. What are these ovals and why are they colorless?
Definition
these parts are cell parts that were metabolically active before staining. They are colorless because the staining will lose its malachite green when rinsed with water.
Term
You do a gram stain of M. luteus, but see that there are cells present that are both purple and red. Explain what you see.
Definition
Because M. luteus is gram positive, you couldv'e stained with safranin for too long or destained too much
Term
You do a gram stain with E. coli and see that half the cells are purple and half the cells are red. Explain what you see.
Definition
Because E. coli is gram negative, you didn't destain enough
Term
At higher magnifications, the light intensity dial should be adjusted that the lamp produces ________ light.
Definition
MORE
Term
We will mostly work with what type of bacteria?
Definition
chemohetertrophic...we must provide carbon source
Term
What are some precautionary steps you should take when using an autoclave?
Definition
use slow exhaust setting when autoclaving liquids, make sure it reads 0 psi before opening the door, stand back, do not swirl test tubes and beakers
Term
hyperthermophiles
Definition
75 to 90
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