BIOL 401: MICROBIOLOGY EXAM 2 QUESTIONS AND
VERIFIED ANSWERS
Typically, which nutrient would be needed at the lowest concentration in a bacterial
culture medium? - Answers - manganese
Which of the following is NOT a mactronutrient required by all microogranisms? -
Answers - chloride
An organism that uses organic compounds from its environment as energy source is
best described as a - Answers - chemotroph
When performing photosynthesis, cyano bacteria such as Antrospira platensis serve as
an example of a - Answers - photoautotroph
When a microorganism obtains energy by oxidizing glucose and passing electrons
through a transport chain to sulfate, which of the following terms best indicates its
metabolic activity? - Answers - anaerobic respiration
Which of the following types of metabolism involves iron (ferrous iron, for example) as
an electron donor and oxygen as a terminal electron acceptor? - Answers - lithotrophy
Which of the following statements is true?
- The vast majority of microorgaisms cannot be grown in the laboratory.
- Micronutrients are present in sufficient quantities for growth as contaminants in water
and glassware.
- Different bacterial species require different essential nutrients from the environment.
- Nitrogen fixation is the conversion of molecular nitrogen into ammonium.
- All of the above - Answers - All of the above are true statements.
What is true regarding minimal media? - Answers - All the chemical components in
minimal media are known and have defined concentrations.
Which type of growth media contains blood components? - Answers - enriched media
The presence of penicillin in a culture medium favors the growth of bacteria that are
resistant to that particular antibiotic. This is an example of - Answers - selective medium
Which of the following nutrient uptake systems does not require cellular energy? -
Answers - facilitated diffusion of glycerol
, A bacterial permease that moves an uncharged sugar molecule into the cell along with
a proton should be considered as an - Answers - electrogenic symporter
Identify the energy source that allows bacteria to scavenge and import siderophores. -
Answers - ATP
Siderophores can help bacterial cells acquire this particular nutrient: - Answers - iron
If the E1 enzyme of the phosphotransferase (PTS) was nonfunctional, which of the
following would be a most likely consequence? - Answers - Import of all substrates
dependent on the PTS would eventually stop.
Which of the following statement is true regarding microbial biofilms? - Answers - They
may contain multiple species of bacteria.
Which of the following is the correct order of how biofilms usually develop? - Answers -
attachment --> microcolonies --> EPS production --> maturation --> dissolution and
dispersal
Why do some autotrophoic cyanobacteria, such as Anabaena, develop heterocysts? -
Answers - Heterocysts allow nitrogen fixation to occur separately from oxygenic
photosynthesis.
*Suppose you ingest 20 cells of Listeria monocytogenes in a piece of cheese. They all
survive the stomach and enter the intestine. Suppose further that the sum total of
subsequent bacterial replication and death (caused by the host) produces an average
generation time of 2 hours and you feel sick when there are 10^6 bacteria. Roughly how
much time will elapse before you feel sick? - Answers - 31 hours
A human pathogen is most likely a(n) - Answers - mesophile.
Compared to when it is growing at a higher temperature, a bacterium growing at a lower
temperature (but still within its optimal range) should have more of the following in its
lipid membrane: - Answers - unsaturated fatty acids
A particular species of bacterium has a growth range between 15 and 42ºC, with
optimum growth at 37ºC. If the doubling time at 37º is 40 mins, then at 27ºC the
doubling time should be approximately - Answers - 80 minutes
The synthesis of compatible solutes is most likely associated with which of the following
organisms? - Answers - halophiles
One reason many microorganisms are killed by pasteurization is that - Answers -
proteins denature.
VERIFIED ANSWERS
Typically, which nutrient would be needed at the lowest concentration in a bacterial
culture medium? - Answers - manganese
Which of the following is NOT a mactronutrient required by all microogranisms? -
Answers - chloride
An organism that uses organic compounds from its environment as energy source is
best described as a - Answers - chemotroph
When performing photosynthesis, cyano bacteria such as Antrospira platensis serve as
an example of a - Answers - photoautotroph
When a microorganism obtains energy by oxidizing glucose and passing electrons
through a transport chain to sulfate, which of the following terms best indicates its
metabolic activity? - Answers - anaerobic respiration
Which of the following types of metabolism involves iron (ferrous iron, for example) as
an electron donor and oxygen as a terminal electron acceptor? - Answers - lithotrophy
Which of the following statements is true?
- The vast majority of microorgaisms cannot be grown in the laboratory.
- Micronutrients are present in sufficient quantities for growth as contaminants in water
and glassware.
- Different bacterial species require different essential nutrients from the environment.
- Nitrogen fixation is the conversion of molecular nitrogen into ammonium.
- All of the above - Answers - All of the above are true statements.
What is true regarding minimal media? - Answers - All the chemical components in
minimal media are known and have defined concentrations.
Which type of growth media contains blood components? - Answers - enriched media
The presence of penicillin in a culture medium favors the growth of bacteria that are
resistant to that particular antibiotic. This is an example of - Answers - selective medium
Which of the following nutrient uptake systems does not require cellular energy? -
Answers - facilitated diffusion of glycerol
, A bacterial permease that moves an uncharged sugar molecule into the cell along with
a proton should be considered as an - Answers - electrogenic symporter
Identify the energy source that allows bacteria to scavenge and import siderophores. -
Answers - ATP
Siderophores can help bacterial cells acquire this particular nutrient: - Answers - iron
If the E1 enzyme of the phosphotransferase (PTS) was nonfunctional, which of the
following would be a most likely consequence? - Answers - Import of all substrates
dependent on the PTS would eventually stop.
Which of the following statement is true regarding microbial biofilms? - Answers - They
may contain multiple species of bacteria.
Which of the following is the correct order of how biofilms usually develop? - Answers -
attachment --> microcolonies --> EPS production --> maturation --> dissolution and
dispersal
Why do some autotrophoic cyanobacteria, such as Anabaena, develop heterocysts? -
Answers - Heterocysts allow nitrogen fixation to occur separately from oxygenic
photosynthesis.
*Suppose you ingest 20 cells of Listeria monocytogenes in a piece of cheese. They all
survive the stomach and enter the intestine. Suppose further that the sum total of
subsequent bacterial replication and death (caused by the host) produces an average
generation time of 2 hours and you feel sick when there are 10^6 bacteria. Roughly how
much time will elapse before you feel sick? - Answers - 31 hours
A human pathogen is most likely a(n) - Answers - mesophile.
Compared to when it is growing at a higher temperature, a bacterium growing at a lower
temperature (but still within its optimal range) should have more of the following in its
lipid membrane: - Answers - unsaturated fatty acids
A particular species of bacterium has a growth range between 15 and 42ºC, with
optimum growth at 37ºC. If the doubling time at 37º is 40 mins, then at 27ºC the
doubling time should be approximately - Answers - 80 minutes
The synthesis of compatible solutes is most likely associated with which of the following
organisms? - Answers - halophiles
One reason many microorganisms are killed by pasteurization is that - Answers -
proteins denature.
