MCB 101 Exam 3 Practice Questions With Complete
Solutions
A Durham tube is used to look for __________________
Correct Answers gas production
All the biochemical tests we perform in this exercise should be
incubated at ________ for ____________ Correct Answers
37C, 48 hours
An unknown bacteria is tested for lysine decarboxylase activity.
The media shown below has been incubated for 24 hours at 37
degrees celsius. The color is yellow/brown... Correct Answers
Lysine decarboxylase activity cannot be determined
Biochemical tests can be used to ________ Correct Answers
distinguish between different groups of bacteria
Electron transport driven by a difference in proton concentration
across a membrane allows for the regeneration of NAD+ in
fermenting bacteria Correct Answers False
For each fo the media listed below, is it an agar plate, an agar
slant, or a broth medium?
Agar Slant:
Agar Plate:
Agar Slant:
Broth Media: Correct Answers Agar Slant: Kligler
Agar Plate: MacConkey Agar Slant: Citric Acid Broth Media:
Mannitol
, For each of the following components of XLD media, select
whether it is "Selective", "Differential", or "Neither": Yeast
extract, sodium deoxycholate, agar, and lactose Correct Answers
Neither: Yeast Extract Selective: Sodium Deoxycholate
Neither: Agar
Differential: Lactose
How long will you incubate your biochemical tests before
scoring them? Correct Answers 48 hours
How many colony types should you see on your first streak
plates after they have been incubated? Correct Answers 2
How many isolated colonies will you streak onto your
Salmonella Chromagenic agar plate? Correct Answers 4
How should Salmonella colonies appear on MacConkey, XLD,
and Salmonella Chromagenic media? Correct Answers
MacConkey: beige
XLD: Red with black center
Salmonella Chromagenic: purple
How will you start your biochemical tests once your TA has
approved your dichotomous key? Correct Answers One of each
test listed in your dichotomous key started on the same day
How would the following changes influence the sensitivity of
PCR primers for the target DNA sequence in a PCR reaction?
Correct Answers Increase: Few mismatches between the target
DNA and primer sequences
Decrease: Decrease the annealing temperatures
Solutions
A Durham tube is used to look for __________________
Correct Answers gas production
All the biochemical tests we perform in this exercise should be
incubated at ________ for ____________ Correct Answers
37C, 48 hours
An unknown bacteria is tested for lysine decarboxylase activity.
The media shown below has been incubated for 24 hours at 37
degrees celsius. The color is yellow/brown... Correct Answers
Lysine decarboxylase activity cannot be determined
Biochemical tests can be used to ________ Correct Answers
distinguish between different groups of bacteria
Electron transport driven by a difference in proton concentration
across a membrane allows for the regeneration of NAD+ in
fermenting bacteria Correct Answers False
For each fo the media listed below, is it an agar plate, an agar
slant, or a broth medium?
Agar Slant:
Agar Plate:
Agar Slant:
Broth Media: Correct Answers Agar Slant: Kligler
Agar Plate: MacConkey Agar Slant: Citric Acid Broth Media:
Mannitol
, For each of the following components of XLD media, select
whether it is "Selective", "Differential", or "Neither": Yeast
extract, sodium deoxycholate, agar, and lactose Correct Answers
Neither: Yeast Extract Selective: Sodium Deoxycholate
Neither: Agar
Differential: Lactose
How long will you incubate your biochemical tests before
scoring them? Correct Answers 48 hours
How many colony types should you see on your first streak
plates after they have been incubated? Correct Answers 2
How many isolated colonies will you streak onto your
Salmonella Chromagenic agar plate? Correct Answers 4
How should Salmonella colonies appear on MacConkey, XLD,
and Salmonella Chromagenic media? Correct Answers
MacConkey: beige
XLD: Red with black center
Salmonella Chromagenic: purple
How will you start your biochemical tests once your TA has
approved your dichotomous key? Correct Answers One of each
test listed in your dichotomous key started on the same day
How would the following changes influence the sensitivity of
PCR primers for the target DNA sequence in a PCR reaction?
Correct Answers Increase: Few mismatches between the target
DNA and primer sequences
Decrease: Decrease the annealing temperatures
