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Bio 2051 test 2 nyugen Questions | Questions Solved 100% Correct | Verified Answers
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Bio 2051 test 2 nyugen Questions | Questions Solved 100% Correct | Verified Answers
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Bio 2051 test 2 nyugen Questions | Questions Solved100% Correct | Verified Answers
How might understanding the natural growth requirements of a microorganism help a
researcher?
It is essential for its cultivation.
It is important to understand the natural environments in which the organism can thrive (or fail
to thrive).
We can make predictions based on what the organism can and cannot grow on, as to what
metabolic pathways are present in the cell.
None of these statements is correct.
All of these statements are correct. - ✔✔all are correct
Why does growing in a salty environment pose a challenge?
Salty environments pose a challenge to cellular life both because of the osmotic stress it places
on the cell (in a salty environment we would expect much the water in the cell to escape to the
outside).
Water has more activity (e.g., of the water that remains, more is available due to the
interaction of water with the ions) in a salty environment.
Water contains strong hydrogen bonds that allows more of it to interact with the ions.
All of these statements are correct.
None of these statements is correct. - ✔✔Salty environments pose a challenge to cellular
life both because of the osmotic stress it places on the cell (in a salty environment we would
expect much the water in the cell to escape to the outside).
Select the incorrect statement.
,Complex media are derived in part from components where the specific concentrations of each
nutrient are unknown.
Examples of complex media include media formulated from crude yeast or animal (beef or
brain) extracts.
In defined media, the chemical identity and concentration of all components are known.
In defined media, yeast, animal, and plant tissue is present.
None of these choices are incorrect. - ✔✔In defined media, yeast, animal, and plant tissue is
present.
Pure cultures can be obtained by:
streaking the mixture of bacteria on solid media in a petri dish. If properly performed the
sequential streaking of an initial mixture of bacteria onto different sections of the petri dish will
result in single colonies of bacteria that are spatially separated from one another. Each colony
arises from a single cell that underwent several rounds of cell division.
spreading several dilutions of bacteria containing liquid onto plates of solid nutrient media one
is able to isolate single colonies that grow.
diluting the bacteria into molten nutrient agar at a temperature that should not kill the
bacteria and rapidly pouring a plate from this mixture. The pour plate method is best for
isolating individual, non-overlapping colonies but is the most laborious and can kill some of the
bacteria if the temperature is not well controlled or if the bacteria is particularly heat sensitive.
all - ✔✔all of these statements are correct
Unculturable microorganisms can be characterized by determining the types of bacteria
present in a sample by:
isolating DNA from all cells and amplifying and sequencing the 20S ribosomal DNA.
isolating DNA from all cells and amplifying and sequencing the 60S ribosomal DNA.
isolating DNA from all cells and amplifying and sequencing the 16S ribosomal DNA.
isolating RNA from all cells and amplifying and sequencing the 16S ribosomal RNA.
, isolating RNA from all cells and amplifying and sequencing the 20S ribosomal RNA. -
✔✔isolating DNA from all cells and amplifying and sequencing the 16S ribosomal DNA.
How is temperature used to eliminate microbes or control their growth?
Most, but not all, microorganisms can be killed by elevating the temperature 100 °C (boiling).
Some microbes, however, produce spores that are resistant to temperatures.
Most common pathogens can be removed from milk or juice by brief heating to temperatures
below boiling (a process called pasteurization). This process is widely used because it kills most
pathogens while preserving the properties of the liquid, however many bacteria are not
destroyed during this process and pasteurized milk or juice will spoil after prolonged storage.
Refrigeration is used to impede the growth of microbes and can preserve specimens, food or
media for extended periods whereas, freezing stops the growth of almost all microbes for
indefinite periods and is an excellent way to preserve food or specimens for long term storage.
All of these choices are correct. - ✔✔all of these choices are correct
How do oxidizing agents affect microbes?
Oxidizing agents including peroxides, bleach, iodine, chlorine and ozone all work by stripping
electrons away from proteins, nucleic acids, lipids and cell walls.
Oxidizing agents including peroxides, bleach, iodine, chlorine and ozone all work by stripping
protons away from proteins, nucleic acids, lipids and cell walls.
Oxidizing agents including peroxides, bleach, iodine, chlorine and ozone all work by stripping
neutrons away from proteins, nucleic acids, lipids and cell walls.
Oxidizing agents including peroxides, bleach, iodine, chlorine and ozone all work by stripping
electrons away from carbohydrates.
None of these choices because oxidizing agents do not affect microbes. - ✔✔Oxidizing
agents including peroxides, bleach, iodine, chlorine and ozone all work by stripping electrons
away from proteins, nucleic acids, lipids and cell walls.
The primary difference between organotrophs and lithotrophs is
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