MCB 101 FINAL EXAM PRACTICE QUESTIONS WITH
VERIFIED ANSWERS
Which biochemical test media requires that you remove a specific amount of culture to a
new tube prior to reading the result?
Urease
Lysine Decarboxylase
Indole
Methyl Red - Answers - Methyl Red
Which sugar fermentation test utilizes a Durham tube?
Mannitol
Raffinose
Sucrose
Lactose
Glucose - Answers - Glucose
Which biochemnical test requires a larger inoculum than other the other tests?
Esculin
Citric Acid
Raffinose
Lysine Decarboxylase
Urease - Answers - Urease
Match the appropiate developing reagent with the biochemical tests listed below.
Catalase - Answers - Hydrogen Peroxide
Match the appropiate developing reagent with the biochemical tests listed below.
Phenylalanine Deaminase - Answers - 10% Ferric Chloride
Match the appropiate developing reagent with the biochemical tests listed below.
Voges-Proskauer - Answers - VPI/VPII
Match the appropiate developing reagent with the biochemical tests listed below.
Indole - Answers - Kovac Reagent
Agar Plate vs Agar Slant vs Broth Media
,For each fo the media listed below, is it an agar plate, an agar slant, or a broth medium?
Phenylalanine Deaminase -->
Lysine Decarboxylase -->
Mannitol -->
MacConkey -->
Kligler's Test --> - Answers - Phenylalanine Deaminase --> Agar Slant
Lysine Decarboxylase --> Broth Media
Mannitol --> Broth Media
MacConkey --> Agar Plate
Kligler's Test --> Agar Slant
Why does Kovac Reagent contain isoamyl alcohol?
Isomayl alcohol concentrates the hydrgoen sulfide allowing to react with iron salts.
Isoamyl alcohol reacts with phenylpyruvic acid so that it can bind ferric ions.
Isolamyl alcohol oxidizes acetoin to diacetyl.
Isoamyl alcohol reacts with the products of mixed acid fermentation to turn red.
Isoamyl alcohol concentrates indole allowing it to react with p-
dimethylaminobenzaldehyde. - Answers - 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?
the bottom of the slant is orange while the slant/air interface is red
the entire slant is red and there is dense growth on the slant surface
the entire slant is yellow, and the agar is cracked from excessive gas production
, the bottom of the slant is yellow, the slant/air interface is red, and there is an obvious
black precipitate in the agar
the bottom of the slant is yellow while the slant/air interface is red - Answers - 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 ________________?
measure a specific biochemical capability.
determine exactly how an acid waste product is produced.
distinguish between different groups of bacteria.
determine the identity of a particular acid waste product.
obtain a pure culture of an organism. - Answers - distinguish between different groups
of bacteria.
A Durham tube is used to look for ____________.
production of alkaline waste products.
H2 production.
ability to use a nitrogen source.
acid production.
a color change. - Answers - H2 production.
All the biochemical tests we perform in this exercise should be incubated at _________
for _________ .
30C, 48 hours
37C, 24 hours
30C, 24 hours
37C, 48 hours - Answers - 37C, 48 hours
Which component(s) in MacConkey agar restrict the growth of Gram-positive bacteria?
Bile salts and crystal violet
VERIFIED ANSWERS
Which biochemical test media requires that you remove a specific amount of culture to a
new tube prior to reading the result?
Urease
Lysine Decarboxylase
Indole
Methyl Red - Answers - Methyl Red
Which sugar fermentation test utilizes a Durham tube?
Mannitol
Raffinose
Sucrose
Lactose
Glucose - Answers - Glucose
Which biochemnical test requires a larger inoculum than other the other tests?
Esculin
Citric Acid
Raffinose
Lysine Decarboxylase
Urease - Answers - Urease
Match the appropiate developing reagent with the biochemical tests listed below.
Catalase - Answers - Hydrogen Peroxide
Match the appropiate developing reagent with the biochemical tests listed below.
Phenylalanine Deaminase - Answers - 10% Ferric Chloride
Match the appropiate developing reagent with the biochemical tests listed below.
Voges-Proskauer - Answers - VPI/VPII
Match the appropiate developing reagent with the biochemical tests listed below.
Indole - Answers - Kovac Reagent
Agar Plate vs Agar Slant vs Broth Media
,For each fo the media listed below, is it an agar plate, an agar slant, or a broth medium?
Phenylalanine Deaminase -->
Lysine Decarboxylase -->
Mannitol -->
MacConkey -->
Kligler's Test --> - Answers - Phenylalanine Deaminase --> Agar Slant
Lysine Decarboxylase --> Broth Media
Mannitol --> Broth Media
MacConkey --> Agar Plate
Kligler's Test --> Agar Slant
Why does Kovac Reagent contain isoamyl alcohol?
Isomayl alcohol concentrates the hydrgoen sulfide allowing to react with iron salts.
Isoamyl alcohol reacts with phenylpyruvic acid so that it can bind ferric ions.
Isolamyl alcohol oxidizes acetoin to diacetyl.
Isoamyl alcohol reacts with the products of mixed acid fermentation to turn red.
Isoamyl alcohol concentrates indole allowing it to react with p-
dimethylaminobenzaldehyde. - Answers - 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?
the bottom of the slant is orange while the slant/air interface is red
the entire slant is red and there is dense growth on the slant surface
the entire slant is yellow, and the agar is cracked from excessive gas production
, the bottom of the slant is yellow, the slant/air interface is red, and there is an obvious
black precipitate in the agar
the bottom of the slant is yellow while the slant/air interface is red - Answers - 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 ________________?
measure a specific biochemical capability.
determine exactly how an acid waste product is produced.
distinguish between different groups of bacteria.
determine the identity of a particular acid waste product.
obtain a pure culture of an organism. - Answers - distinguish between different groups
of bacteria.
A Durham tube is used to look for ____________.
production of alkaline waste products.
H2 production.
ability to use a nitrogen source.
acid production.
a color change. - Answers - H2 production.
All the biochemical tests we perform in this exercise should be incubated at _________
for _________ .
30C, 48 hours
37C, 24 hours
30C, 24 hours
37C, 48 hours - Answers - 37C, 48 hours
Which component(s) in MacConkey agar restrict the growth of Gram-positive bacteria?
Bile salts and crystal violet
