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MICROBIOLOGY LAB FINAL EXAM VERSION 2 EXAM NEWEST
2025/2026 ACTUAL EXAM WITH COMPLETE QUESTIONS AND
CORRECT DETAILED ANSWERS (100% VERIFIED ANSWERS)
|ALREADY GRADED A+| ||PROFESSOR VERIFIED||
What other reason other than mixing did you shake the tube after
adding reagent B? - ANSWER-add oxygen gas
Voges-Proskauer)
What chemical if present is reacting with the reagents? -
ANSWER-Acetoin
Red color after the addtion of the reagents for the test with in 60
minutes - ANSWER-positive for 2,3 butanediol fermanation
No red color after the addition of the reagents for the test after 60
minutes - ANSWER-negative for 2,3 butanediol fermanation
(Phenol Red)
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What pH indicator is in this medium? - ANSWER-Phenol Red
(Phenol Red)
What color indicates a modest drop in pH (below 6.8) from the
production of acid? - ANSWER-Yellow
(Phenol Red)
What color indicates a rise in pH from the production of alkaline or
basic products? - ANSWER-Pink
(Phenol Red)
What product does a bubble in the Durham tube indicate? -
ANSWER-Gas (either Hydrogen or Carbon Dioxide or Both)
(Phenol Red)
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When sugars are fermented, what end-products are generated
that can be detected by this test? - ANSWER-Acid and Gas
(Phenol Red)
When proteins are deaminated, what product is generated that
then reacts with water to produce a pH change? - ANSWER-
Ammonia
(Phenol Red)
Yellow tube with bubble in Durham tube - ANSWER-A/G
(Phenol Red)
Yellow tube with NO bubble in Durham tube - ANSWER-A/-
(Phenol Red)
Pink tube with NO bubble in Durham tube - ANSWER-k
(Phenol Red)
MICROBIOLOGY LAB FINAL EXAM VERSION 2 EXAM NEWEST
2025/2026 ACTUAL EXAM WITH COMPLETE QUESTIONS AND
CORRECT DETAILED ANSWERS (100% VERIFIED ANSWERS)
|ALREADY GRADED A+| ||PROFESSOR VERIFIED||
What other reason other than mixing did you shake the tube after
adding reagent B? - ANSWER-add oxygen gas
Voges-Proskauer)
What chemical if present is reacting with the reagents? -
ANSWER-Acetoin
Red color after the addtion of the reagents for the test with in 60
minutes - ANSWER-positive for 2,3 butanediol fermanation
No red color after the addition of the reagents for the test after 60
minutes - ANSWER-negative for 2,3 butanediol fermanation
(Phenol Red)
,2|Page
What pH indicator is in this medium? - ANSWER-Phenol Red
(Phenol Red)
What color indicates a modest drop in pH (below 6.8) from the
production of acid? - ANSWER-Yellow
(Phenol Red)
What color indicates a rise in pH from the production of alkaline or
basic products? - ANSWER-Pink
(Phenol Red)
What product does a bubble in the Durham tube indicate? -
ANSWER-Gas (either Hydrogen or Carbon Dioxide or Both)
(Phenol Red)
, 3|Page
When sugars are fermented, what end-products are generated
that can be detected by this test? - ANSWER-Acid and Gas
(Phenol Red)
When proteins are deaminated, what product is generated that
then reacts with water to produce a pH change? - ANSWER-
Ammonia
(Phenol Red)
Yellow tube with bubble in Durham tube - ANSWER-A/G
(Phenol Red)
Yellow tube with NO bubble in Durham tube - ANSWER-A/-
(Phenol Red)
Pink tube with NO bubble in Durham tube - ANSWER-k
(Phenol Red)
