lab exam 2 Flashcards
this media looks to see if cells secrete amylase to create glucose from starch
starch hydrolysis plate
flooding the starch plate with iodine & seeing a clearing on the media means the organism utilizes
starch
glycosidic bond has to be broken to turn starch into
glucose
tributyrin agar tests bacteria that can break down
fats
an organism that can do lipid hydrolysis will break down _____ into fatty acids
triglycerides
the break down of triglyceride is done by breaking an ______ bond
ester
positive tributyrin test is a _____ around growth
clearing
casein test looks to see if bacteria can break down peptides into ___ ___ by secreting _____
amino acids; protease
break down casein requires breaking _____ bond
peptide
gelatin hydrolysis also looks for organisms that can break a ____ bond
peptide
cells that secrete ______ will break down gelatin into amino acids
gelatinase
positive result for gelatinase is when media does not _____
solidify
DNAse agar contains _____ as an indicator
methyl green
DNAse cleaves ____ bond
phosphodiester
biooxidations in which molecular oxygen can serve as final electron acceptor
aerobic cell respiration
biooxidations in which inorganic ions can serve as a final electron acceptor
anaerobic cell respiration
phenol red is _____ when acidic
yellow
phenol red is ____ when alkaline
fuschia
a biooxidative process not requiring oxygen in which organic substrate serves as final elector receptor
fermentation
the durham tube looks to see what bacteria can make ____ products
acidic
dextrose is ____
glucose
E. coli should be ____ for fermentation of glucose and lactose
positive
pseudomonas should be _____ for fermentation of glucose and lactose
negative
CO2 can be captured in durham tube which is production of ____ ____ accompanied by gas
organic acids
yellow color in Durham tube is ____ for production of acetic acids
positive
IMViC is used to distinguish ____
enterics
what is used to see if tryptophan can be degraded into indole?
sulfide indole motility (SIM) agar
listeria is a disease caused by _____ _____ that is commonly talked about in food safety (dangerous to pregnant women)
listeria monocytogenes
gram -, nonspore forming, rod-shaped “enteric” bacteria (gut microbiome)
bacteriodetes
gram + rods or cocci; includes bacillus, clostridium, staph and lactobacillus (gut microbiome)
firmicutes
more bacteriodetes in comparison to fermicutes can lead to
obesity
more fermicutes in comparison to bacteriodetes can lead to
IBD
kefir is plated on an _____ agar which is selective for what (partially selective; low pH for lactobacilli. (5.5))
LBS, lactobacilli
glucose is a major sugar and _____ source
carbon
on LBS agar, lactobacilli appear as medium sized to large _____ _____
white colonies
kefir dilution plates are kept at
37C
kefir says their probiotics have _____
41.6 x 10^6 CFU/mL
urease is helpful in the identification of _____ _____
proteus vulgaris (will turn pink)
_____ converts urea into ammonia
urease
urea broth contains urea and pH indicator ____ ____
phenol red
a positive test for urease in a bacteria will be a deep pink color in an _____ environment
alkaline
staph and micrococcus are catalase _____
+
strep and enterococcus are catalase ____
-
_______ differentiate mostly among Enterobacteriaceae
decarboxylation
decarboxylation is characterized by remove of _____ under aerobic conditions
carboxyl
what reaction yields amine (cadaverine) and CO2 products
decarboxylation
_____ _____ _____ has glucose supplemented with - lysine; a layer of glycerol is added as well, why?
moellers decarboxylase broth; to exclude oxygen (anaerobic)
the decarboxylase test indicator is ____ ____ ____
brom cresol purple
brom cresol purple is _____ at neutral and _____ but when acid (<5.2)
purple; yellow
decarboxylases are inducible enzymes, which means what?
the microbe must first use the glucose to cause the pH to become acidic
decarboxylase + test will change from what color to what color
purple to yellow (incubated at 37C for 24 hours)
once the decarboxylase medium has been acidified and glucose has been used up what is induced (an additional 24 hours is required to allow microbe to use this)
lysine
for the decarboxylase test after 48 hours a color change from ____ to _____ indicates a positive test for lysine decarboxylase
purple to yellow
phenylalanine slant phenylalanine is deaminated to ____ ____ and ammonia
keto acid
ferric chloride (FeCl3) is a chelating agent used to detect phenylpyruvic acid (keto acid) which turns what color
green
beta galactosidase (ONPG) in bacteria normally converts ______ to galactose and alpha nitrophenol
lactose
beta - galactosidase is an inducible enzyme apart of the ____ ____ encoded by lacz gene
lac operon
alpha-nitrophenol turns ____
yellow
the SIM medium will be tested using kovacs reagent (24 hours after incubation), a positive result is what color
red layer at the top
a positive result for SIM indicates the presence of what
tryptophanase and subsequently production of indole
within the MRVP broth a methyl red test will show a positive result which is
red color after addition of methyl red (production of organic acids)
a positive VP test is development of ____ color after the addition of barritts A & B reagents
red-brown color (production of neutral non-acidic products)
the methyl red test looks to see if microbe can ferment _____ with the production of high concentration of acid end products
glucose
the VP test looks to see if microbe can ferment ____ with the production of neutral end products such as
glucose; acetoin and 2,3-butanediol
barritt’s solution is made up of
alpha-naphthol & KOH
(simmons citrate agar) the citrate media contains ____ ____ as the sole carbon source
sodium citrate
(simmons citrate agar) the citrate media uses ____ ____ as the sole nitrogen source
ammonium salts
simmons citrate the positive result bacteria metabolize _____ back to pyruvate for ATP production
citrate
the products of simmons citrate are
CO2 and sodium carbonate
the indicator in citrate agar is ___ ____
bromthymol blue (from green to blue at alkaline pH)
enzymes brings citrate into the cell
citrate permease
what enzyme breaks down lysine into CO2 and cada something
lysinase
what enzyme breaks down H2O2
catalase
which media tests for anerobic capabilities
thioglycolate
substrate needed for lipase to act on media
tributryn
what is the fat source in LBS agar
polysorbate 80
3 carbon sources for fermentation broth
lactose, glucose and sucrose
organisms that only grow above 70C
extreme (obligate) thermophile
an organism that can live in arctic ice
psychrophile (-10 to 25)
will grow at 37C, with optimum of 45C to 60C
facultative thermophiles
bacteria that can survive at stomach pH of two
E. coli, Lactobacillus, and Helicobacter pylori
7 is the pH optimum for
neutrophile
grow well at pH above 9
alkalophile
pH optimum 1-5 are called
acidophile
what temperatures were used for zenwise, s. wholesome, E. coli, and S. marcescens
4, 20, 37, 60
serratia marcescens pigment shows up at what temperature
20
what are barritts A & B reagents
KOH & Alpha-naphthol
what enzyme turns phenylalanine into phenylpyruvic acid + ammonia
phenylalanine deaminase
what is the CFU/mL equation
colonies counted/amount plated (mL) x diultion
what is the thermophile we used in class
bacillus stearothermophilus
what is mineral oil in decarboxylase and lysine test used for
allow anerobic respiration
