Lab Quiz 11: Exoenzymes, White Blood Cells, and Miscellaneous Topics (Bio 286 - Microbiology) Flashcards
exoenzyme
enzymes that catalyze reactions outside of the cell, such as hydrolyzing macromolecules to smaller molecules for transport into cells
amylase
enzyme that hydrolyzes STARCH (AMYLOSE) (a polymer of glucose) into monomers that can be transported into cells
gram’s iodine to starch agar
reacts with remaining starch in medium to yield a brown color…. if bacteria have degraded the starch a clear zone will be observed around the bacteria and if the bacteria produced or stored starch the bacteria will stain darkly
positive result after adding gram’s iodine
CLEAR ZONE IN STARCH MEDIUM
negative result after adding gram’s iodine
no clear zone in starch medium
DNase
ability of bacteria to hydrolyze DNA in the growth medium to its component nucleotides
1 M HCl
added to DNA agar, causing DNA to come out of solution and turn the medium opaque… a clear zone around the colonies indicates that the DNA has been hydrolyzed
gelatinase
hydrolyzes gelatin (protein produced by partial hydrolysis of collagen extracted from animal tissues)…. after two days of bacterial growth, the culture is placed into an ice bucket to chill to determine if the medium resolidifies, indicating presence or lack of gelatin if it doesn’t solidify or does, respectively
positive result of chilling gelatin culture on ice
CULTURE REMAINS LIQUID
negative result of chilling gelatin culture on ice
culture gels
lipase
ability of bacteria to hydrolyze triglycerides to glycerol and fatty acids… tributryin (glycerol esterified to three butyric acids) emulsified with Polysorbate (Tween) 80 is base medium… if present, the medium around the bacteria will grow less opaque/halo around growth
positive result of lipase plate
CLEAR ZONE
negative result of lipase plate
no change in medium
leukocyte (white blood cell) types
neutrophil, lymphocyte, monocyte, eosinophil, basophile
neutrophil
approximately 62% of white blood cells… most common white blood cell… type of granulocyte and are main phagocytic cells in circulation… lobed nucleus (3-5 lobes connected by thin strands of nuclein)
elevated neutrophil numbers indicates
microbial infection
lymphocyte
approximately 30% of white blood cells… include B-cells and T-cells of adaptive immune response
elevated lymphocyte numbers indicates
infection (or rarely cancer)
monocyte
approximately 5% of white blood cells… immune cells differentiate into tissue macrophage and dendritic cells… important antigen presenting cells
elevated monocyte numbers indicates
chronic infections
eosinophil
approximately 3% of white blood cells… cells filled with pink stained granules… function is to primarily deal with worm infections but are also associated with type I hypersensitivity (allergies)
elevated eosinophil numbers indicates
worm infection or allergies
basophile
less than 1% of white blood cells… cells filled with purple stained granules (that often obscure view of nucleus)
elevated basophile numbers indicates
anemia or microbial infections (like chicken pox)
what enzyme caused bubbles after addition of H2O2?
catalase
what kind of media is MSA?
selective and differential
what antibiotic is on the A disk?
bacitracin
what organism was used to inoculate the tests above?
staph. aureus
what is the target of lysozyme?
peptidoglycan
what distinguishes coliforms from non-coliforms?
ferment lactose
what color is a positive citrate agar test?
blue
what did the methyl red test check for?
acid production
which amino acid was degraded to cause a positive indole test?
tryptophan
how should a TSI tube appear if a coliform is used to inoculate it?
A/A
what compound makes EF broth selective?
sodium azide
what makes MSA a differential media?
mannitol
what color does a positive bile esculin test turn?
black
what enzyme performs this reaction: 2 H2O2 -> 2 H2O + O2
catalase
what type of hemolysis causes complete clearing of blood agar?
beta
how is wastewater disinfected at the Big Rapids plant?
UV light
what is the main purpose of secondary wastewater treatment in Big Rapids?
reduce biological oxygen demand
what did we add to our DNA plates to visualize the DNase exoenzyme action?
HCl
what type of relationship do cows have with their rumen bacteria?
mutualism
what type of relationship do bacteriophage have with bacteria?
parasitism
what term refers to the ability of some bacteria to take up naked DNA?
competent
if you filter 10 mL of undiluted water and observe 15 colonies, how many cfu/100 mL were in that sample?
150 cfu/mL (# of colonies * dilution factor / filter volume) x 100
if a water sample gave 50 blue and 10 red colonies, what would be the most likely source of contamination?
human feces
what is the phenotype of the lactose operon mutant shown to the right?
constitutive
based upon the complementation results, what is the genotype of the mutant?
lacI-
what color did our positive urea plates turn?
pink
what chemical is detected in a positive voges proskauer test?
acetoin
what color is a negative citrate agar test?
green
which amino acid was degraded to turn the TSI tubes black?
cysteine
if a microbe can ferment glucose but neither lactose nor sucrose, how would its TSI tube appear?
K/A
with respect to 10 minutes and 70C, what is the thermal death point?
80C
why was bacillus cereus resistant to heat killing?
forms endospores
which of these scientists studied genetic transformation in bacteria?
griffith and avery
what color did our fecal coliform colonies turn?
blue
what makes mEA agar selective?
sodium azide
what was the pore size of the filters that we used for water quality testing?
0.45 micrometers
how many fecal coliforms are acceptable in treated drinking water?
0 cfu/100 mL
what makes mFC media differential?
lactose
what type of UV light is most germicidal?
UVC
what is the most common type of damage caused by UV light in bacteria?
thymine dimers
which of the following microbes was an acidophile in our lab?
saccharomyces cerevisiae
which of the following microbes was most halotolerant in our lab?
staphylococcus aureus
which of the following microbes was an alkalinophile in our lab?
alcaligenes faecalis
which of the following microbes was a psychrophile in our lab?
pseudomonas fluorescens
which of the following microorganisms was most antibiotic susceptible in our lab?
staphylococcus aerues
which of the following microorganisms was most antibiotic resistant in our lab?
candida albicans
where would an antiseptic most likely be used?
on your arm
what is the target of streptomycin’s action?
70S ribosome
germicidal soap contains triclosan. what group of chemicals includes this compound (triclosan)?
phenolic
which of the following disks had a drug that these bacteria were most resistant to?
Disk B (largest zone of inhibition)
what phase of growth does this culture exhibit at 40 minutes?
lag
using the points at 120 and 200 minutes, what is the slope (m) of the line?
log (y1) - log (y2) / x1 - x2
using the slope from previously, what is the generation time (g) of the culture in minutes?
g = log(2) / m
what phase of growth does this culture exhibit at 200 minutes?
log
what sort of organism grows best at 5C?
psychrophile
what sort of organism grows best at pH 5?
acidophile
what sort of organism requires 5% NaCl for growth?
halophile
what sort of organism growth best at 60C?
thermophile
suppose that you inoculated both of the plates illustrated below with the same pure bacterial culture. plate A was incubated for 48 hours at 35C in a GasPak jar. Plate B was incubated as usual in our incubator at 35C for 48 hours. what sort of microbial growth do these results suggest?
aerobe (only plate B had growth)
where would this organism grow in a thioglycolate tube? (it is an aerobe)
top only
what is the tube dilution factor if you add 2 mL of sample to 18 mL of diluent?
10x … (sample + diluent / sample)
what is the tube dilution factor if you add 0.2 mL of sample to 0.8 mL of diluent?
5x … (sample + diluent / sample)
what is the tube dilution factor of tube A above?
100x … (sample + diluent / sample)
what is the tube dilution factor of tube B above?
50x … (sample + diluent / sample)
what is the serial dilution factor of tube E above?
5x10^6 … (all TDFs multiplied together)
what does CFU stand for?
colony forming units
what term refers to the “holes” made in bacterial cultures by phage?
plaque
what is the tube dilution factor for tube A below?
100x … (sample + diluent / sample)
what is the serial dilution factor for tube D below?
10^5x … (multiply all TDFs together)
based on the plate from tube D, how many cells were in the original flask below?
3.7x10^7 cfu/mL … (CFU * SDF / volume plated)
which of the following microbes causes malaria?
plasmodium falciparum
trichomonas vaginalis differs from many other protozoa because it does not form what structures?
cyst
what protist is shown to the right?
balantidium coli
what type of asexual spores appeared like little footballs?
macroconidia
which of these fungi is “black bread mold”?
rhizopus stolonifer
what fungus is illustrated in the picture to the right?
penicillium chrysogenum
what does “fast” mean in acid-fast stain?
the primary stain does not rinse out with acid
most motile bacteria use _____ for motility
flagella
what color did mycobacterium smegmatis appear when acid-fast stained?
red
what type of flagellar arrangement is illustrated to the right?
peritrichous
who created the gram stain?
hans christian gram
what color do gram negative cells appear?
pink
what chemical acts as the primary stain in the gram stain?
crystal violet
escherichia coli, a gram negative rod, appeared as purple rods when gram stained. how do you explain this result?
the decolorizer was not applied long enough
what stain is used in both the gram and endospore stain?
saphranin
what was the mordant for the endospore stain?
heat
which plate had the most endospores on it?
tryptic soy agar
what are most capsules formed from?
polysaccharides
what is the function of bacterial capsules?
immune evasion
which of the following bacterial genera most often form endospores?
clostridium and bacillus
what color is the shortest wavelength that humans can see?
violet
what does Dr. Franklund say is the most dangerous thing in our lab?
the bunsen burners
what term refers to the ability to distinguish two objects as being separate?
resolution
when you switch from the 10X to 40X objective, which of these increases?
magnification
which of these microbe categories is the most common that we will use in our lab?
BSL-1
what would the total magnification be if using a 10X ocular and 25x objective lens?
250x
how would the letter q appear when viewed through our microscopes?
b
what term refers to a macroscopic pile of microscopic cells?
colony
what term refers to the shape and arrangement of these cells?
staphylococcus
what is the size of one ocular division?
1.4 micrometers
