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MCB 101 FINAL EXAM NEWEST 2024 ACTUAL EXAM QUESTIONS AND CORRECT ANSWERS | A+ GRADE STUDYGUIDE
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MCB 101 FINAL EXAM NEWEST 2024 ACTUAL EXAM QUESTIONS AND CORRECT ANSWERS | A+ GRADE STUDYGUIDE
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MCB 101 FINAL EXAM NEWEST 2024ACTUAL EXAM QUESTIONS AND
CORRECT ANSWERS | A+ GRADE
STUDYGUIDE
Why does Kovac Reagent contain isoamyl alcohol?
A. Isoamyl alcohol reacts with the products of mixed acid
fermentation to turn red.
B. Isoamyl alcohol concentrates indole allowing it to react
with p-dimethylaminobenzaldehyde.
C. Isomayl alcohol concentrates the hydrogen sulfide
allowing to react with iron salts.
D. Isoamyl alcohol reacts with phenylpyruvic acid so that it
can bind ferric ions.
E. Isolamyl alcohol oxidizes acetoin to diacetyl. Correct
Answer B. Isoamyl alcohol concentrates indole allowing it
to react with p-dimethylaminobenzaldehyde.
You run a Kligler's test on the Gram-negative organism,
Serratia marcescens, to see if it produces hydrogen
sulfide when grown in the presence of sulfur-containing
amino acids. After 48 h, you score the test and find that S.
marcescens gives a positive result. What is the most likely
appearance of the Kligler's test agar slant when you score
it?
A. The bottom of the slant is orange while the slant/air
interface is red
B. The bottom of the slant is yellow, the slant/air interface
is red, and there is an obvious black precipitate in the agar
,C. The entire slant is yellow, and the agar is cracked from
excessive gas production
D. The bottom of the slant is yellow while the slant/air
interface is red
E. The entire slant is red and there is dense growth on the
slant surface Correct Answer B. The bottom of the slant is
yellow, the slant/air interface is red, and there is an
obvious black precipitate in the agar
Biochemical tests can be used to ________________?
A. determine whether or not acid is being produced.
B. determine exactly how an acid waste product is
produced.
C. determine the identity of a particular acid waste
product.
D. determine the identity of a particular gas that is being
produced.
E. obtain a pure culture of an organism. Correct Answer A.
determine whether or not acid is being produced.
A Durham tube is used to look for ____________.
A. production of alkaline waste products.
B. ability to use a nitrogen source.
C. H2 production.
D. ability to use a carbon source.
E. acid production. Correct Answer C. H2 production.
All the biochemical tests we perform in this exercise
should be incubated at _________ for _________ .
A. 37C, 48 hours
B. 37C, 24 hours
,C. 30C, 24 hours
D. 30C, 48 hours Correct Answer A. 37C, 48 hours
Which is not an enzymatic function detected with the
biochemical tests described in this exercise?
A. Antibiotic resistance
B. Utilization of a particular sugar for energy
C. Breaking down an organic compound for the cell to use
D. Tolerate oxygen Correct Answer A. Antibiotic
resistance
MacConkey agar is both a selective and differential
medium.
A. True
B. False Correct Answer A. True
Biochemical tests can be used to determine both whether
a bacteria can grow utilizing a nutrient and how the
nutrient is being utilized.
A. False
B. True Correct Answer A. False
Which component(s) in MacConkey agar restrict the
growth of Gram-positive bacteria?
A. Bile salts and crystal violet
B. Mannitol
C. Peptone and sodium chloride
D. Esculin and peptone Correct Answer A. Bile salts and
crystal violet
, If the culture used to inoculate the biochemical tests in the
previous question was contaminated with a second
organisms, how would this effect the results?
A. It would not be possible to identify the organisms using
those biochemical test results.
B. Organism A would have been the correct identification
or the organism.
C. Organism B would have been the correct identification
or the organism.
D. Organism D would have been the correct identification
or the organism.
E. It would not effect the results since some of the tests
were negative. Correct Answer A. It would not be possible
to identify the organisms using those biochemical test
results.
Match the following statements with whether they describe
the Dichotmous Key or Best Fit approach to identification
of bacterial species.
1. A misread in scoring a biochemical test prevents
reaching the correct identification
2. Start 1 biochemical test at a time and select the next
based on the result of the previous.
3. A misread in scoring a biochemical test may not prevent
reaching the correct identification
4. Requires less time to identify a bacterial species
Correct Answer 1. Dichotomous Key: A misread in scoring
a biochemical test prevents reaching the correct
identification
2. Dichotomous Key: Start 1 biochemical test at a time and
select the next based on the result of the previous.
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