MCB 4403 Exam 2 vocab questions well
answered to pass
Which of the following techniques would be best to use to study extremophiles that cannot be
cultured in normal laboratory conditions? - correct answer ✔✔the polymerase chain reaction to
amplify the DNA to have enough for further analysis
growth rate of different kinds of bacteria at different pressures. - correct answer ✔✔*
Basophiles: Grows in high pressure environment
* Baro tolerant: Grow up to a certain pressure and @ that high pressure it dies.
* Baro sensitive: Organisms die from increased pressure.
What kind of cellular changes would be expected in oil-eating microbes moved from a warmer
environment to the Arctic? - correct answer ✔✔increased unsaturated fatty acids in membrane
phospholipids and development of trehalose being used as a cryoprotectant
How would genetically engineered proteins likely change when grown in organisms living in cold
temperatures? - correct answer ✔✔The proteins would likely be more flexible as the mutations
increasing flexibility would be selected for in this environment.
Which of the following adaptations helps microbes growing at the bottom of the ocean? -
correct answer ✔✔polyunsaturated fats in phospholipids to help increase membrane fluidity
What would be the effect of water evaporating from a puddle without anything else acting on
it? - correct answer ✔✔The water activity would decrease due to an increase in the
concentration of dissolved substances.
,Which of the following is a common compatible solute used by microbes to prevent water loss
in a hypertonic medium? - correct answer ✔✔K+ ions
If halophiles require high environmental concentrations of salt (NaCl), then why do they have
such high intracellular concentrations of potassium? - correct answer ✔✔They keep sodium
levels low by replacing it with potassium since sodium can be used for symport with other
solutes.
Which of the following would have the greatest effect on cell function due to changes in pH? -
correct answer ✔✔disrupting protein secondary structure, thus decreasing enzyme activity
Escherichia coli growing under slightly alkaline conditions produces organic acids to help negate
the extra hydroxide ions. This cell now gets dosed with tomato juice. How is it likely to respond?
- correct answer ✔✔
Molecular oxygen can form superoxide radicals and other harmful oxygen-containing molecules
that damage nucleic acids, proteins, and lipids. Therefore, which of the following choices would
best explain the benefit to microbes that grow in the presence of oxygen? - correct answer
✔✔It serves as the final electron acceptor in aerobic respiration, providing more energy in the
cell
A research lab is using DNA microarrays to examine gene expression in Salmonella enterica
during stress. It was noted that when exposed to nutrient limitations, 20 new genes were
expressed (as compared to normal laboratory growth conditions); when exposed to oxidative
stress, 24 new genes were expressed; and when exposed to low pH, 15 new genes were
expressed. The lab then subjected the bacteria to growth in macrophage phagolysosomes,
which mimicked the previous three conditions, and noted 59 new genes being expressed.
Which of the following would best explain this result? - correct answer ✔✔The result is most
likely a coincidence since although the conditions would add up to 59 if you just totaled the
changes, we need to consider that some of the genes for the different stressors would overlap,
thus causing a lower number; some genes wouldn't be expressed under the combined
conditions, which would also lower the number; and some new genes would likely be expressed
, due to the unrecognized stress of growing in the phagolysosome, which would increase the
number since this is a new condition.
A disinfectant was added to a culture of bacteria containing 20,000,000 CFUs per milliliter to
start. Since the D value of the disinfectant is 1 minute and 20 seconds, there will be...CFUs per
ml after 4 minutes. - correct answer ✔✔20,000 CFU's
phenol coefficient - correct answer ✔✔is the number obtained from the test used to compare
the effectiveness of a test substance to phenol.
antiparallel - correct answer ✔✔DNA strands run in opposite directions
5'-3'
3'-5'
Molecular cloning - correct answer ✔✔1.) Plasmid vector + Foreign DNA
2.) Both cleaved by EcoRi endonuclease
3.) Annealing
DNA Ligase
4.) Plasmid Chimera
DNA ligase - correct answer ✔✔facilitates the joining of DNA strands together by catalyzing the
formation of a phospho-diester bond
Exonuclease - correct answer ✔✔Enzyme that cleaves DNA from the end.
Histone - correct answer ✔✔Protein that binds eukaryotic DNA& compacts chromosomes in
nucleosomes
answered to pass
Which of the following techniques would be best to use to study extremophiles that cannot be
cultured in normal laboratory conditions? - correct answer ✔✔the polymerase chain reaction to
amplify the DNA to have enough for further analysis
growth rate of different kinds of bacteria at different pressures. - correct answer ✔✔*
Basophiles: Grows in high pressure environment
* Baro tolerant: Grow up to a certain pressure and @ that high pressure it dies.
* Baro sensitive: Organisms die from increased pressure.
What kind of cellular changes would be expected in oil-eating microbes moved from a warmer
environment to the Arctic? - correct answer ✔✔increased unsaturated fatty acids in membrane
phospholipids and development of trehalose being used as a cryoprotectant
How would genetically engineered proteins likely change when grown in organisms living in cold
temperatures? - correct answer ✔✔The proteins would likely be more flexible as the mutations
increasing flexibility would be selected for in this environment.
Which of the following adaptations helps microbes growing at the bottom of the ocean? -
correct answer ✔✔polyunsaturated fats in phospholipids to help increase membrane fluidity
What would be the effect of water evaporating from a puddle without anything else acting on
it? - correct answer ✔✔The water activity would decrease due to an increase in the
concentration of dissolved substances.
,Which of the following is a common compatible solute used by microbes to prevent water loss
in a hypertonic medium? - correct answer ✔✔K+ ions
If halophiles require high environmental concentrations of salt (NaCl), then why do they have
such high intracellular concentrations of potassium? - correct answer ✔✔They keep sodium
levels low by replacing it with potassium since sodium can be used for symport with other
solutes.
Which of the following would have the greatest effect on cell function due to changes in pH? -
correct answer ✔✔disrupting protein secondary structure, thus decreasing enzyme activity
Escherichia coli growing under slightly alkaline conditions produces organic acids to help negate
the extra hydroxide ions. This cell now gets dosed with tomato juice. How is it likely to respond?
- correct answer ✔✔
Molecular oxygen can form superoxide radicals and other harmful oxygen-containing molecules
that damage nucleic acids, proteins, and lipids. Therefore, which of the following choices would
best explain the benefit to microbes that grow in the presence of oxygen? - correct answer
✔✔It serves as the final electron acceptor in aerobic respiration, providing more energy in the
cell
A research lab is using DNA microarrays to examine gene expression in Salmonella enterica
during stress. It was noted that when exposed to nutrient limitations, 20 new genes were
expressed (as compared to normal laboratory growth conditions); when exposed to oxidative
stress, 24 new genes were expressed; and when exposed to low pH, 15 new genes were
expressed. The lab then subjected the bacteria to growth in macrophage phagolysosomes,
which mimicked the previous three conditions, and noted 59 new genes being expressed.
Which of the following would best explain this result? - correct answer ✔✔The result is most
likely a coincidence since although the conditions would add up to 59 if you just totaled the
changes, we need to consider that some of the genes for the different stressors would overlap,
thus causing a lower number; some genes wouldn't be expressed under the combined
conditions, which would also lower the number; and some new genes would likely be expressed
, due to the unrecognized stress of growing in the phagolysosome, which would increase the
number since this is a new condition.
A disinfectant was added to a culture of bacteria containing 20,000,000 CFUs per milliliter to
start. Since the D value of the disinfectant is 1 minute and 20 seconds, there will be...CFUs per
ml after 4 minutes. - correct answer ✔✔20,000 CFU's
phenol coefficient - correct answer ✔✔is the number obtained from the test used to compare
the effectiveness of a test substance to phenol.
antiparallel - correct answer ✔✔DNA strands run in opposite directions
5'-3'
3'-5'
Molecular cloning - correct answer ✔✔1.) Plasmid vector + Foreign DNA
2.) Both cleaved by EcoRi endonuclease
3.) Annealing
DNA Ligase
4.) Plasmid Chimera
DNA ligase - correct answer ✔✔facilitates the joining of DNA strands together by catalyzing the
formation of a phospho-diester bond
Exonuclease - correct answer ✔✔Enzyme that cleaves DNA from the end.
Histone - correct answer ✔✔Protein that binds eukaryotic DNA& compacts chromosomes in
nucleosomes
