Quiz P2 Flashcards
An operon is a useful genetic element, because it
An operon is a useful genetic element, because it
translates DNA sequence into amino acid sequence.
encourages the binding of ribosomes in the correct location.
encourages the binding of RNA polymerase.
allows coordinated expression of multiple related genes in prokaryotes.
allows coordinated expression of multiple related genes in prokaryotes.
Proofreading of newly-synthesized DNA is important because __________.
Hints
Hint 1.
[[DNA Synthesis]] DNA is the primary repository of an organisms’ heredity, and natural selection acts upon the traits coded by this information.
Proofreading of newly-synthesized DNA is important because __________.
a high fidelity in the copying of DNA is necessary for good heredity
any protein made from mutated DNA will not function properly
the cell will invariably die if any mutations occur during replication
DNA pol III has a high error rate during replication
a high fidelity in the copying of DNA is necessary for good heredity
hich of the following is formed on the lagging strand during DNA synthesis?
Which of the following is formed on the lagging strand during DNA synthesis?
replisomes
DNA secondary structures
Okazaki fragments
RNA polymeras
Okazaki fragments
replication involves the synthesis of an RNA primer on one strand of the DNA.
DNA replication involves the synthesis of an RNA primer on one strand of the DNA.
True
False
T
During DNA replication Okazaki fragments are linked together by________, an enzyme that creates phosphodiester bonds between nicked fragments of DNA.
During DNA replication Okazaki fragments are linked together by________, an enzyme that creates phosphodiester bonds between nicked fragments of DNA.
topoisomerase
exopolymerase
DNA ligase
DNA gyrase
DNA ligase
DNA replication is bidirectional in prokaryotes with circular chromosomes.
DNA replication is bidirectional in prokaryotes with circular chromosomes.
True
False
T
The template for RNA polymerase is ________, and the new RNA chain is ________ to the template.
The template for RNA polymerase is ________, and the new RNA chain is ________ to the template.
DNA / antiparallel and complementary
DNA / parallel and identical
an independent RNA segment / antiparallel and complementary
an independent RNA segment / parallel and identical
DNA / antiparallel and complementary
The function of RNA polymerase is to
The function of RNA polymerase is to
catalyze the formation of phosphodiester bonds between ribonucleotides.
catalyze the formation of phosphodiester bonds between deoxyribonucleotids.
cleave mRNA to remove introns.
activate tRNAs.
catalyze the formation of phosphodiester bonds between ribonucleotides.
Which of the following is NOT correct regarding DNA and RNA synthesis?
DNA is the template for both DNA and RNA synthesis.
Both processes require an RNA primer to begin.
The template strand is antiparallel to the newly synthesized strand.
The overall direction of chain growth is from the 5’ to 3’ end.
Both processes require an RNA primer to begin.
Termination of RNA synthesis is ultimately determined by
Termination of RNA synthesis is ultimately determined by
special protein factors.
specific nucleotide sequences on the template strand.
exhaustion of RNA polymerase activity.
terminases.
specific nucleotide sequences on the template strand.
Stop codons are also called ________ codons.
Stop codons are also called ________ codons.
conversion
nonsense
degeneracy
release facto
nonsense
A triplet of bases on an mRNA molecule is known as a(n)
A triplet of bases on an mRNA molecule is known as a(n)
anticodon.
ribosome-binding sequence.
codon.
amino acid.
codon.
Which of the following is an example of one codon?
Which of the following is an example of one codon?
GCCATT
CCGUAA
CAG
CATT
CAG
Throughout the living world, the genetic code is generally universal; however, there are slight variations.
Throughout the living world, the genetic code is generally universal; however, there are slight variations.
True
False
T
The process of synthesizing proteins involves translating one “language,” nucleic acid sequences, into another “language,” amino acid sequences. The cellular component that does the actual translating from codons to amino acids is the __________.
Hints
Hint 1.
[[Translation]] Ribosomes, proteins, messenger RNA, and transfer RNAs all have specific roles during translation.
The process of synthesizing proteins involves translating one “language,” nucleic acid sequences, into another “language,” amino acid sequences. The cellular component that does the actual translating from codons to amino acids is the __________.
mRNA
tRNA
rRNA
RNA polymerase
tRNA
The Tat system is involved in The Tat system is involved in protein folding. transcriptional initiation. protein synthesis. protein secretion.
protein secretion.
The time interval required for the formation of two cells from one is called the
The time interval required for the formation of two cells from one is called the
growth rate.
generation time.
division rate.
growth time.
generation time.
The process by which two prokaryotic cells arise from one is known as
The process by which two prokaryotic cells arise from one is known as
binary fission.
meiosis.
mitosis.
conjugation
binary fission.
The activity of MinC and MinD direct whether a bacterial cell will be coccoid or bacillus shaped.
The activity of MinC and MinD direct whether a bacterial cell will be coccoid or bacillus shaped.
True
False
False
Fts proteins are essential for bacterial cell division because they __________.
Hints
Fts proteins are essential for bacterial cell division because they __________.
are responsible for peptidoglycan synthesis
are responsible for forming the divisome
are responsible for pulling apart the two copies of the chromosome
All of the listed responses are correct.
All of the listed responses are correct.
acterium that lacks the mreB gene will have a ________ shape.
A bacterium that lacks the mreB gene will have a ________ shape.
coccoid
bacillus
vibrio
short bacillus
coccoid
In which bacteria would you find MreB proteins and why?
Hints
Hint 1.
[[MreB protein]] MreB is the major shape-determining factor in Bacteria. It forms a basic cytoskeleton directly underneath the plasma membrane.
In which bacteria would you find MreB proteins and why?
Staphylococcus aureus, because it is coccus-shaped
Mycoplasma pneumoniae, because it is pleomorphic
Neisseria gonorrhea, because it is coccus-shaped
E. coli, because it is rod-shaped.
E. coli, because it is rod-shaped.
To determine the specific growth rate of a bacterial population, it is essential to know
To determine the specific growth rate of a bacterial population, it is essential to know
turbidity measurements and the total number of cells in the population at varied time points.
total number of cells in the population at varied time points.
turbidity measurements at varied time points.
cell concentrations at varied time points and the generation time
total number of cells in the population at varied time points.
a bacterial culture contains 1 cell at time zero, 4 cells after 1 hour, and 16 cells after 2 hours, then all EXCEPT which of the following is true?
Hints
Hint 1.
[[Growth rates]] Bacterial cell numbers double with each generation.
If a bacterial culture contains 1 cell at time zero, 4 cells after 1 hour, and 16 cells after 2 hours, then all EXCEPT which of the following is true?
The generation time, g, is constant
The division rate, v, is constant.
The growth rate is constant.
The growth rate is increasing with each generation.
The growth rate is increasing with each generation.
Optical density and viable cell concentration are LEAST proportional to each other during
Optical density and viable cell concentration are LEAST proportional to each other during
stationary phase.
lag phase.
death phase.
exponential growth phase.
death phase.
In a batch culture, bacterial cultures typically exhibit four different phases of growth. In which phase are the cells rapidly synthesizing proteins, but cell numbers are not changing?
Hints
Hint 1.
[[Phases of growth]] Cells inoculated into fresh media must adjust to the new substrates and conditions.
In a batch culture, bacterial cultures typically exhibit four different phases of growth. In which phase are the cells rapidly synthesizing proteins, but cell numbers are not changing?
death phase
exponential phase
lag phase
stationary phase
lag phase
Which choice illustrates best what occurs in the stationary phase of bacterial growth?
Hints
Which choice illustrates best what occurs in the stationary phase of bacterial growth?
cryptic growth, where the number of new cells equals the number of dying cells
unbalanced growth, where the number of dead cells increases while the number of new cells decreases
balanced growth, where the number of dead cells equals the number of new cells
cryptic growth, where the number of dead cells decreases while the number of new cells increases
cryptic growth, where the number of new cells equals the number of dying cells
ime between inoculation and the beginning of growth is usually called the
The time between inoculation and the beginning of growth is usually called the
lag phase.
log phase.
dormant phase.
death phase.
lag phase.
The duration of logarithmic growth would increase if bacterial cells divided into three equal daughter cells rather than two.
The duration of logarithmic growth would increase if bacterial cells divided into three equal daughter cells rather than two.
True
False
False
The lag phase does NOT occur if all the cells in the culture are viable.
The lag phase does NOT occur if all the cells in the culture are viable.
True
False
False
In both lag and stationary phase, there is no net increase or decrease in viable cells.
In both lag and stationary phase, there is no net increase or decrease in viable cells.
True
False
True
The rates of exponential growth (in the exponential phase) vary greatly according to the bacterial species as well as the bioavailable nutrients.
The rates of exponential growth (in the exponential phase) vary greatly according to the bacterial species as well as the bioavailable nutrients.
True
False
True
The death phase applies to individual cells rather than populations.
The death phase applies to individual cells rather than populations.
True
False
False
Direct microscope counting of stained cells is an accurate method for calculating the exact number of cells in a sample.
Direct microscope counting of stained cells is an accurate method for calculating the exact number of cells in a sample.
True
False
True
The number of colonies obtained in a plate count does NOT depend on the
The number of colonies obtained in a plate count does NOT depend on the
incubation time.
type of culture medium.
size of the colonies.
inoculum volume.
size of the colonies.
For most purposes of studying bacterial isolates, viable counting usually gives accurate information about the number of active cells present in a culture volume.
For most purposes of studying bacterial isolates, viable counting usually gives accurate information about the number of active cells present in a culture volume.
True
False
True
When viable cell concentrations are too high to count on an agar medium, it is most common to use larger sized plates to increase the surface area for counting the colonies.
When viable cell concentrations are too high to count on an agar medium, it is most common to use larger sized plates to increase the surface area for counting the colonies.
True
False
False
A microbe growing in a refrigerator is likely
A microbe growing in a refrigerator is likely
mesophilic.
psychrophilic.
psychrotolerant or psychrophilic.
hyperthermophilic.
psychrotolerant or psychrophilic.
Bacteria that are able to grow in humans and cause disease have likely evolved to be
Bacteria that are able to grow in humans and cause disease have likely evolved to be
hyperthermophiles.
mesophiles.
thermophiles.
psychrophiles
mesophiles
Most mesophilic organisms can grow in a temperature range of
Most mesophilic organisms can grow in a temperature range of
20-40°C.
10-20°C.
0-15°C.
50-65°C.
20-40°C.
One reason food is refrigerated to control microbial growth is because irreversible cell damage is more likely to occur at low rather than high temperatures.
One reason food is refrigerated to control microbial growth is because irreversible cell damage is more likely to occur at low rather than high temperatures.
True
False
False
Relative to enzymes in mesophilic microorganisms, which of the following is NOT characteristic of enzymes in psychrophiles?
Relative to enzymes in mesophilic microorganisms, which of the following is NOT characteristic of enzymes in psychrophiles?
decreased beta sheets
less ionic bonds
less hydrogen bonds
decreased alpha helices
decreased alpha helices
A bacterium such as a snow alga that is able to survive a cold temperature is called a psychrophile.
A bacterium such as a snow alga that is able to survive a cold temperature is called a psychrophile.
True
False
False
Which of these statements is/are TRUE?
Which of these statements is/are TRUE?
The most thermophilic prokaryotes are species of Archaea.
In general, prokaryotic organisms can grow at higher temperatures than eukaryotic organisms.
Nonphototrophic organisms are able to grow at higher temperatures than phototrophic organisms.
All of the statements are true.
All of the statements are true.
Some microbes can grow in boiling water.
Some microbes can grow in boiling water.
True
False
T
Due to the relationship between the rate of enzyme catalysis and temperature, organisms living in boiling hot springs are also rapid growers with fast doubling times.
Due to the relationship between the rate of enzyme catalysis and temperature, organisms living in boiling hot springs are also rapid growers with fast doubling times.
True
False
False
Taq polymerase was isolated from a thermophile and is used in the polymerase chain reaction (PCR) technique because it does not become inactivated at high temperatures.
Taq polymerase was isolated from a thermophile and is used in the polymerase chain reaction (PCR) technique because it does not become inactivated at high temperatures.
True
False
T
Where would it be best to isolate bacteria from to study the mechanism of the sodium motive force?
Where would it be best to isolate bacteria from to study the mechanism of the sodium motive force?
hot springs
soda lakes
volcanoes
human gut
soda lakes
A bacterium’s pH optimum reflects the optimal pH of its intracellular environment.
A bacterium’s pH optimum reflects the optimal pH of its intracellular environment.
True
False
False
In principle, the chemical composition of membranes in obligate acidophiles could be distinguished from neutrophiles.
In principle, the chemical composition of membranes in obligate acidophiles could be distinguished from neutrophiles.
True
False
T
The ratio of the vapor pressure of the air in equilibrium with a substance to the vapor pressure of pure water is known as
The ratio of the vapor pressure of the air in equilibrium with a substance to the vapor pressure of pure water is known as
positive water balance.
osmosis.
water activity.
vapor activity.
water activity.
Organisms able to live in environments with high sugar concentrations are
Organisms able to live in environments with high sugar concentrations are
xerophiles.
anaerobic fermenting bacteria.
osmophiles.
halotolerant
osmophiles.
When water activity is low, an organism must
When water activity is low, an organism must
increase its external solute concentration.
decrease its internal solute concentration.
decrease its external solute concentration.
increase its internal solute concentration.
increase its internal solute concentration.
A halotolerant facultative anaerobic bacterium would grow BEST in a ________ environment.
A halotolerant facultative anaerobic bacterium would grow BEST in a ________ environment.
oxygenated non-saline
oxygen depleted non-saline
oxygenated saline
oxygen depleted saline
oxygenated non-saline
Superoxide dismutase and catalase work together to convert superoxide into
Superoxide dismutase and catalase work together to convert superoxide into
carbon dioxide.
peroxide.
oxygen.
ozone
oxygen
A bacterium containing ________ provided with hydrogen peroxide will produce oxygen bubbles.
A bacterium containing ________ provided with hydrogen peroxide will produce oxygen bubbles.
catalase
superoxide reductase
superoxide dismutase
peroxidase
catalase
Which of the following forms of oxygen is/are generally toxic to living organisms?
Which of the following forms of oxygen is/are generally toxic to living organisms?
superoxide, hydrogen peroxide, and hydroxyl radicals are all toxic
hydrogen peroxide
superoxide
hydroxyl radical
superoxide, hydrogen peroxide, and hydroxyl radicals are all toxic
During a growth curve of Aliivibrio fischeri, when would you expect to see the strongest bioluminescence?
During a growth curve of Aliivibrio fischeri, when would you expect to see the strongest bioluminescence?
lag phase
late log to early stationary phase
early to middle log phase
middle to late stationary phase
late log to early stationary phase
A bacterium that either partially or fully catabolizes an acyl-homoserine lactone will likely disrupt
A bacterium that either partially or fully catabolizes an acyl-homoserine lactone will likely disrupt
attenuation.
quorum sensing.
endospore formation.
chemotaxis.
quorum sensing.
ALL viral particles
ALL viral particles
exhibit cell lysis under a particular condition.
are metabolically inert.
contain an envelope to prevent its degradation outside of a host.
are smaller than bacterial cells.
are metabolically inert.
Viral replication is
Viral replication is
dependent on the host cell’s DNA, RNA, enzymes, and metabolism.
dependent on the host cell’s DNA and RNA.
independent of both the host cell’s DNA and the host cell’s enzymes and metabolism.
independent of the host cell’s DNA but dependent on the host cell’s enzymes and metabolism.
independent of the host cell’s DNA but dependent on the host cell’s enzymes and metabolism.
For bacteriophages and animal viruses ________ is the step in the viral life cycle that determines host cell or tissue specificity.
For bacteriophages and animal viruses ________ is the step in the viral life cycle that determines host cell or tissue specificity.
penetration
attachment
synthesis
assembly
attachment
What are the consequences of a viral infection of an animal cell?
What are the consequences of a viral infection of an animal cell?
rapid lysis or latent infections
Outcomes vary from rapid lysis to persistent infections, latent infections, or cancer.
lysogeny followed by eventual lysis
lysis or lysogeny
Outcomes vary from rapid lysis to persistent infections, latent infections, or cancer.
The term “phage” is generally reserved for the viruses that infect
The term “phage” is generally reserved for the viruses that infect
bacteria.
multiple species.
animals.
plants.
bacteria
Reverse transcriptase is a(n) Reverse transcriptase is a(n) RNA-dependent RNA polymerase. RNA-dependent DNA polymerase. DNA-dependent RNA polymerase. DNA-dependent DNA polymerase.
RNA-dependent DNA polymerase
a natural population of diverse slow-growing prokaryotic cells, what type of viruses would you expect to be most common?
In a natural population of diverse slow-growing prokaryotic cells, what type of viruses would you expect to be most common?
enveloped viruses
lytic bacteriophages
icosahedral viruses
temperate bacteriophages
lytic bacteriophages
