MIP302 - Final Exam QUESTIONS WITH
DETAILED VERIFIED ANSWERS (100%
CORRECT ANSWERS) / ALREADY
GRADED A+
thermophiles ✔✔bacteria that live in environments with elevated temperatures (above
131°F)
super/hyper thermophile ✔✔bacteria that live in environments with extremely elevated
temperatures (above 300°F)
Differential Media ✔✔allows for growth of bacteria, but differentiates bacteria based on
some characteristic appearance on a media type
Selective media ✔✔allows for certain types of bacteria to grow (inhibits others)
Aerobic bacteria ✔✔require atmospheric oxygen
microaerophilic bacteria ✔✔Require atmospheric oxygen but at reduced levels
facultative anaerobes ✔✔Grow with or without oxygen (better with oxygen)
obligate anaerobe ✔✔grow in absense of atmospheric oxygen
Ambient air ✔✔Normal air
candle jar ✔✔reduced levels of O2, higher levels of CO2
GasPak ✔✔reduced environment (devoid of O2)
,Redox indicators for Gaspak and Candle jar ✔✔Redox indicator methylene blue (blue when
oxidized, white in reduced state)
Catalase Test ✔✔To see if bacteria produces enzyme catalase; add 3% H2O2 to a DRY smear
of bacteria; produces bubbles=(+); delayed/no bubbles=(-)
Oxidase Test ✔✔To see if bacteria produces cytochrome oxidase (uses cytochrome C and
cytocrhome oxidase in ETC); uses Oxidrop as reagent; blue/maroon=oxidized, (+); colorless=
reduced, (-); 3 MIN
PR Glucose Broth ✔✔Testing for glucose fermentation; Differential media (ability to ferment
carb); phenol red indicator (yellow in acidic, red in basic); contains peptone and beef extract
in PR broth; Durham tube put in tube to catch gas; yellow=(+); red=(-); 18-24 hours
Nitrate Broth ✔✔Differential media [ability to reduce nitrate (NO3) to nitrite (NO2)] using
anaerobic resp.; Nitrate A and Nitrate B reagents (react w/ nitrite--> red); RESULTS: red
during first round, (+) nitrate reductase, (-) nitrite reductase; Colorless during first round,
inconclusive, add zinc; Red during second round (Nitrate A, B, and zinc) (-) for nitrate and
nitrite reductase; Colorless during second round (+) nitrate and nitrite reductase; 48 HOURS
MacConkey Agar ✔✔To test for lactose fermentation of Gram (-) rods; differential media
(lactose fermentation); selective media (grows Gram - enteric bacilli, inhibits Gram - cocci
and Gram +); neutral red reagent (red in acidic, yellow in basic); contains peptone and beef
extract; RESULTS: red/dark-pink colonies surrounded by zone of bile salt, strong lactose
fermenter; colorless colonies, do not ferment lactose; if no growth, cannot make
conclusions about lactose fermentation; 18-24 HOURS
Phenylethyl Alcohol (PEA) Agar ✔✔Test for Gram (+) growth; Selective (selective component
1/4 phenylethyl OH); not as stringent as MacConkey; RESULTS: growth, most likely Gram (+)
but have to do a Gram stain to check; 18-24 HOURS
Blood Agar (BAP) ✔✔Used to cultivate medically significant bacteria; all-purpose media;
differential (ability to hemolyze red blood cells); includes TSA and sheep red blood cells;
RESULTS: BETA, complete hemolysis, clear zone surrounding colonies; ALPHA, incomplete
lysis, green-ish brown area surrounding colony; GAMMA, no lysis; Don't look at colony itself
to determine results; 24 HOURS
, Pseudosel Agar (Cetrimide Agar) ✔✔Used to isolate and identify Pseudomonas aeruginosa;
Selective (P. aeruginosa can grow, all others inhibited bc of cetrimide); Differential (produce
pyocyanin); can see under room lighting; RESULTS: blue/green colonies, positive result, P.
aeruginosa; 18-24 HOURS
Pseudomonas Agar F ✔✔Used to differentiate bacteria based on ability to produce pigment
fluorescein (differential); all-purpose medium; contains magnesium and potassium salts
(enhance fluorescein production); should be visualized under UV, even tho can see green
pigment in room lighting; RESULTS: glowing under UV, produces fluorescein, (+); 18-24
HOURS
enteric bacteria ✔✔Gram negative facultative anaerobic rods
coliforms ✔✔Gram negetaive rods that ferment lactose and produce gas, facultative
anaerobes, and do not produce spores
tryptophanase ✔✔enzyme produced by bacteria that can use tyrptophan as a carbon source
tryptophan ✔✔catabolized into indole, pyruvic acid, and ammonia
tryptone broth ✔✔medium for indole test
48 ✔✔indole test is incubated for __ hours
Kovac's reagent ✔✔added to broth after incubation in indole test
present ✔✔if bacterium produces tryptophanase, indole will be ______ in the broth
absent ✔✔if bacterium does not produce tryptophanase, indole will be ______ in the broth
DETAILED VERIFIED ANSWERS (100%
CORRECT ANSWERS) / ALREADY
GRADED A+
thermophiles ✔✔bacteria that live in environments with elevated temperatures (above
131°F)
super/hyper thermophile ✔✔bacteria that live in environments with extremely elevated
temperatures (above 300°F)
Differential Media ✔✔allows for growth of bacteria, but differentiates bacteria based on
some characteristic appearance on a media type
Selective media ✔✔allows for certain types of bacteria to grow (inhibits others)
Aerobic bacteria ✔✔require atmospheric oxygen
microaerophilic bacteria ✔✔Require atmospheric oxygen but at reduced levels
facultative anaerobes ✔✔Grow with or without oxygen (better with oxygen)
obligate anaerobe ✔✔grow in absense of atmospheric oxygen
Ambient air ✔✔Normal air
candle jar ✔✔reduced levels of O2, higher levels of CO2
GasPak ✔✔reduced environment (devoid of O2)
,Redox indicators for Gaspak and Candle jar ✔✔Redox indicator methylene blue (blue when
oxidized, white in reduced state)
Catalase Test ✔✔To see if bacteria produces enzyme catalase; add 3% H2O2 to a DRY smear
of bacteria; produces bubbles=(+); delayed/no bubbles=(-)
Oxidase Test ✔✔To see if bacteria produces cytochrome oxidase (uses cytochrome C and
cytocrhome oxidase in ETC); uses Oxidrop as reagent; blue/maroon=oxidized, (+); colorless=
reduced, (-); 3 MIN
PR Glucose Broth ✔✔Testing for glucose fermentation; Differential media (ability to ferment
carb); phenol red indicator (yellow in acidic, red in basic); contains peptone and beef extract
in PR broth; Durham tube put in tube to catch gas; yellow=(+); red=(-); 18-24 hours
Nitrate Broth ✔✔Differential media [ability to reduce nitrate (NO3) to nitrite (NO2)] using
anaerobic resp.; Nitrate A and Nitrate B reagents (react w/ nitrite--> red); RESULTS: red
during first round, (+) nitrate reductase, (-) nitrite reductase; Colorless during first round,
inconclusive, add zinc; Red during second round (Nitrate A, B, and zinc) (-) for nitrate and
nitrite reductase; Colorless during second round (+) nitrate and nitrite reductase; 48 HOURS
MacConkey Agar ✔✔To test for lactose fermentation of Gram (-) rods; differential media
(lactose fermentation); selective media (grows Gram - enteric bacilli, inhibits Gram - cocci
and Gram +); neutral red reagent (red in acidic, yellow in basic); contains peptone and beef
extract; RESULTS: red/dark-pink colonies surrounded by zone of bile salt, strong lactose
fermenter; colorless colonies, do not ferment lactose; if no growth, cannot make
conclusions about lactose fermentation; 18-24 HOURS
Phenylethyl Alcohol (PEA) Agar ✔✔Test for Gram (+) growth; Selective (selective component
1/4 phenylethyl OH); not as stringent as MacConkey; RESULTS: growth, most likely Gram (+)
but have to do a Gram stain to check; 18-24 HOURS
Blood Agar (BAP) ✔✔Used to cultivate medically significant bacteria; all-purpose media;
differential (ability to hemolyze red blood cells); includes TSA and sheep red blood cells;
RESULTS: BETA, complete hemolysis, clear zone surrounding colonies; ALPHA, incomplete
lysis, green-ish brown area surrounding colony; GAMMA, no lysis; Don't look at colony itself
to determine results; 24 HOURS
, Pseudosel Agar (Cetrimide Agar) ✔✔Used to isolate and identify Pseudomonas aeruginosa;
Selective (P. aeruginosa can grow, all others inhibited bc of cetrimide); Differential (produce
pyocyanin); can see under room lighting; RESULTS: blue/green colonies, positive result, P.
aeruginosa; 18-24 HOURS
Pseudomonas Agar F ✔✔Used to differentiate bacteria based on ability to produce pigment
fluorescein (differential); all-purpose medium; contains magnesium and potassium salts
(enhance fluorescein production); should be visualized under UV, even tho can see green
pigment in room lighting; RESULTS: glowing under UV, produces fluorescein, (+); 18-24
HOURS
enteric bacteria ✔✔Gram negative facultative anaerobic rods
coliforms ✔✔Gram negetaive rods that ferment lactose and produce gas, facultative
anaerobes, and do not produce spores
tryptophanase ✔✔enzyme produced by bacteria that can use tyrptophan as a carbon source
tryptophan ✔✔catabolized into indole, pyruvic acid, and ammonia
tryptone broth ✔✔medium for indole test
48 ✔✔indole test is incubated for __ hours
Kovac's reagent ✔✔added to broth after incubation in indole test
present ✔✔if bacterium produces tryptophanase, indole will be ______ in the broth
absent ✔✔if bacterium does not produce tryptophanase, indole will be ______ in the broth
