©JOSHCLAY 2024/2025. YEAR PUBLISHED 2024.
MCB2010L Final Exam Questions with
100% Correct Answers | Already Passed
What is fluid thioglycollate broth (FTB)? - ✔✔It is prepared as a basic
medium or with a variety of substances, depending on the needs of the
organism being cultivated. It is appropriate for a broad variety of aerobic
and anaerobic, and fastidious (requiring specific nutrients to grow) and non
fastidious organisms. Well adapted for strict anaerobes and
microaerophiles.
What are the key components of FTB? - ✔✔Yeast extract, pancreatic
digest of casein, dextrose, sodium thioglycollate, L-cystine, and resazurin.
-yeast extract and casein provide nutrients
-sodium thioglycollate and L-cystine reduce oxygen to water
-resazurin is an indicator of oxygen
What purpose does resazurin dye serve in FTB? - ✔✔Oxygen indicator.
Pink when oxidized, colorless when reduced.
,©JOSHCLAY 2024/2025. YEAR PUBLISHED 2024.
What is the application of FTB? - ✔✔Can be modified to promote growth of
a wide variety of fastidious to non fastidious microorganisms. It can be
used to illustrate microbial growth representing all levels of oxygen
tolerance. However, it generally is associated with the cultivation of
anaerobic and microaerophilic bacteria.
Why is it preferred to use fresh FTB medium over old medium? -
✔✔Oxygen removed during autoclaving will diffuse back into the medium
as the tubes cool to room temperature. This produces a gradient of
concentrations from aerobic (comparable to air) at the top to anaerobic at
the bottom. Fresh media will appear clear to straw coloured with a pink
region at the top, where the dye has become oxidized. The use of old
medium will cause the aerobic region of the tube to grow, indicating
widespread oxidation throughout the tube.
Where would you expect to see growth on FTB medium of a strict aerobe,
anaerobe, microaerophile, facultative anaerobe, and an aerotolerant
anaerobe? - ✔✔-Strict aerobe: at the top of the broth, where oxygen is
abundant
-Anaerobe: at the bottom of the broth, where oxygen is not present
,©JOSHCLAY 2024/2025. YEAR PUBLISHED 2024.
-Microaerophile: in the middle of the broth where oxygen is present, but not
in large amounts
-Facultative anaerobe: concentrated at the top (grows best when most
oxygen is present), but spread throughout (can grow anaerobically)
-Aerotolerant anaerobe: growth relatively evenly throughout (anaerobic, but
tolerates oxygen presence)
Consider resazurin dye. Considering the major application of this medium,
which is more desirable, a thick coloured or a thin coloured band? - ✔✔A
thin coloured band would be more desirable, as it would indicate that the
medium is more fresh. The older the medium, the more oxidation occurs
within the media, creating the indicator band to expand. Certain bacteria
will not be able to grow or the results of their growth will become skewed.
Where is the resazurin located in the broth column? - ✔✔At the very top of
the broth, forming a band.
Why is the FTB broth pink at the surface of the medium? - ✔✔This is where
the most oxygen is present.
Which type of organism would most likely be affected negatively by the use
of old FTB media? - ✔✔Strict (obligate) anaerobes; these organisms are
, ©JOSHCLAY 2024/2025. YEAR PUBLISHED 2024.
inhibited by the presence of oxygen, therefore an abundance of oxygen in
the tube may produce limited growth by these organisms.
Which type of organism would most likely be positively affected by the use
of old FTB media? - ✔✔Strict (obligate) aerobes; the abundance of oxygen
in the media will provide a tremendous advantage to these organism's
growth, as they need sufficient amounts of oxygen to produce.
Which type of organism would be least affected by the use of old FTB
media? - ✔✔Aerotolerant anaerobes; these bacteria continue their
production anaerobically in the presence of oxygen. Oxygen presence will
neither inhibit, nor fuel their growth.
What is the GasPak Anaerobic System? - ✔✔A plastic jar in which we
create anaerobic, microaerophilic, or CO2 enriched conditions, depending
on the specific needs of the bacteria being cultivated.
What components are required for the anaerobic jar? - ✔✔Chemical gas
generator packet containing sodium borohydride and sodium bicarbonate,
and a paper indicator strip saturated in methylene blue and resazurin.
Palladium acts as a catalyst for the reaction that will produce the necessary
conditions within the jar.
MCB2010L Final Exam Questions with
100% Correct Answers | Already Passed
What is fluid thioglycollate broth (FTB)? - ✔✔It is prepared as a basic
medium or with a variety of substances, depending on the needs of the
organism being cultivated. It is appropriate for a broad variety of aerobic
and anaerobic, and fastidious (requiring specific nutrients to grow) and non
fastidious organisms. Well adapted for strict anaerobes and
microaerophiles.
What are the key components of FTB? - ✔✔Yeast extract, pancreatic
digest of casein, dextrose, sodium thioglycollate, L-cystine, and resazurin.
-yeast extract and casein provide nutrients
-sodium thioglycollate and L-cystine reduce oxygen to water
-resazurin is an indicator of oxygen
What purpose does resazurin dye serve in FTB? - ✔✔Oxygen indicator.
Pink when oxidized, colorless when reduced.
,©JOSHCLAY 2024/2025. YEAR PUBLISHED 2024.
What is the application of FTB? - ✔✔Can be modified to promote growth of
a wide variety of fastidious to non fastidious microorganisms. It can be
used to illustrate microbial growth representing all levels of oxygen
tolerance. However, it generally is associated with the cultivation of
anaerobic and microaerophilic bacteria.
Why is it preferred to use fresh FTB medium over old medium? -
✔✔Oxygen removed during autoclaving will diffuse back into the medium
as the tubes cool to room temperature. This produces a gradient of
concentrations from aerobic (comparable to air) at the top to anaerobic at
the bottom. Fresh media will appear clear to straw coloured with a pink
region at the top, where the dye has become oxidized. The use of old
medium will cause the aerobic region of the tube to grow, indicating
widespread oxidation throughout the tube.
Where would you expect to see growth on FTB medium of a strict aerobe,
anaerobe, microaerophile, facultative anaerobe, and an aerotolerant
anaerobe? - ✔✔-Strict aerobe: at the top of the broth, where oxygen is
abundant
-Anaerobe: at the bottom of the broth, where oxygen is not present
,©JOSHCLAY 2024/2025. YEAR PUBLISHED 2024.
-Microaerophile: in the middle of the broth where oxygen is present, but not
in large amounts
-Facultative anaerobe: concentrated at the top (grows best when most
oxygen is present), but spread throughout (can grow anaerobically)
-Aerotolerant anaerobe: growth relatively evenly throughout (anaerobic, but
tolerates oxygen presence)
Consider resazurin dye. Considering the major application of this medium,
which is more desirable, a thick coloured or a thin coloured band? - ✔✔A
thin coloured band would be more desirable, as it would indicate that the
medium is more fresh. The older the medium, the more oxidation occurs
within the media, creating the indicator band to expand. Certain bacteria
will not be able to grow or the results of their growth will become skewed.
Where is the resazurin located in the broth column? - ✔✔At the very top of
the broth, forming a band.
Why is the FTB broth pink at the surface of the medium? - ✔✔This is where
the most oxygen is present.
Which type of organism would most likely be affected negatively by the use
of old FTB media? - ✔✔Strict (obligate) anaerobes; these organisms are
, ©JOSHCLAY 2024/2025. YEAR PUBLISHED 2024.
inhibited by the presence of oxygen, therefore an abundance of oxygen in
the tube may produce limited growth by these organisms.
Which type of organism would most likely be positively affected by the use
of old FTB media? - ✔✔Strict (obligate) aerobes; the abundance of oxygen
in the media will provide a tremendous advantage to these organism's
growth, as they need sufficient amounts of oxygen to produce.
Which type of organism would be least affected by the use of old FTB
media? - ✔✔Aerotolerant anaerobes; these bacteria continue their
production anaerobically in the presence of oxygen. Oxygen presence will
neither inhibit, nor fuel their growth.
What is the GasPak Anaerobic System? - ✔✔A plastic jar in which we
create anaerobic, microaerophilic, or CO2 enriched conditions, depending
on the specific needs of the bacteria being cultivated.
What components are required for the anaerobic jar? - ✔✔Chemical gas
generator packet containing sodium borohydride and sodium bicarbonate,
and a paper indicator strip saturated in methylene blue and resazurin.
Palladium acts as a catalyst for the reaction that will produce the necessary
conditions within the jar.
