Quiz P3 Flashcards
(113 cards)
1
Q
The growth of viruses in a culture is described as a one-step growth curve, because
virion numbers show no increase during intracellular replication and can only be counted after the virions burst from the host cell.
assembly and release actually occur in one step.
there is only one step in the viral life cycle which leads to only one replicative cycle in a culture.
the eclipse phase prevents the plating and enumeration of virions although new virions are produced at a steady rate during the eclipse phase.
A
virion numbers show no increase during intracellular replication and can only be counted after the virions burst from the host cell.
2
Q
When a virus enters a host cell in which it can replicate, the process is called a(n)
infection.
excision.
prophage.
insertion
A
infection
3
Q
Viral replication occurs
Viral replication occurs
extracellularly.
intracellularly.
both intracellularly and extracellularly.
either intracellularly or extracellularly, depending on the virus involved.
A
intracellularly
4
Q
Viruses have both an intracellular and an extracellular form.
Viruses have both an intracellular and an extracellular form.
True
False
A
T
5
Q
Penetration requires that the entire virus is inserted within the host.
Penetration requires that the entire virus is inserted within the host.
True
False
A
F
6
Q
Viruses can redirect host metabolic functions.
Viruses can redirect host metabolic functions.
True
False
A
T
7
Q
lytic infection results in death of the host cell.
A lytic infection results in death of the host cell.
True
False
A
T
8
Q
e concentration of infectious plaque forming units (pfu) per volume of fluid is known as the
The concentration of infectious plaque forming units (pfu) per volume of fluid is known as the
virulence.
titer.
infectivity.
fluid infectivity.
A
titer
9
Q
The use of ________ is the easiest and most effective way of studying many animal and plant viruses.
The use of ________ is the easiest and most effective way of studying many animal and plant viruses.
prophages
live hosts
bacterial cultures
tissue or cell culture
A
tissue or cell culture
10
Q
Viruses infecting ________ are typically the easiest to grow in the laboratory.
Viruses infecting ________ are typically the easiest to grow in the laboratory.
plants
fungi
animals
prokaryotes
A
prokaryotes
11
Q
When solutions of host cells and infectious virions are mixed and spread on an agar plate, ________ form where viruses lyse the host cells.
When solutions of host cells and infectious virions are mixed and spread on an agar plate, ________ form where viruses lyse the host cells.
prophages
colonies
plaques
insertion sequences
A
plaques
12
Q
Bacteriophage have a ________ complex structure than animal viruses, because ________.
Bacteriophage have a ________ complex structure than animal viruses, because ________.
more / the bacteriophage must penetrate the peptidoglycan cell wall
less / there prokaryotic cells have a simple structure compared to eukaryotic cells
more / bacteriophages must be coated by lipopolysaccharide to attach to bacterial cells
less / the bacteriophage does not have to penetrate the nucleus
A
more / the bacteriophage must penetrate the peptidoglycan cell wall
13
Q
Virions infecting some bacteria possess the enzyme ________ that makes a small hole in the bacterial cell wall, allowing the viral nucleic acid to enter.
Virions infecting some bacteria possess the enzyme ________ that makes a small hole in the bacterial cell wall, allowing the viral nucleic acid to enter.
infectase
lysozyme
peptidoglycanase
nuclease
A
lysozyme
14
Q
Cellular receptors may be composed of Cellular receptors may be composed of carbohydrates. lipids. proteins. combinations of proteins, carbohydrates, and/or lipids.
A
combinations of proteins, carbohydrates, and/or lipids.
15
Q
T4 genes are transcribed by host RNA polymerase, yet the transcription of T4 genes is carefully controlled so that groups of T4 genes are transcribed at specific times after infection. How is this accomplished?
T4 genes are transcribed by host RNA polymerase, yet the transcription of T4 genes is carefully controlled so that groups of T4 genes are transcribed at specific times after infection. How is this accomplished?
Rolling circle replication of the viral genome ensures that the genes are available for transcription in the correct order.
Early and middle T4 genes encode for proteins that modify the activity of sigma factors and host RNA polymerase to regulate the expression of T4 genes.
Early T4 genes encode for proteolytic enzymes that destroy the host RNA polymerase. Subsequently a viral polymerase is created that transcribes the middle and late genes in the correct order.
Each group of T4 genes has a different promoter that indicates that order in which they should be transcribed in based on the affinity of the promoter for the host RNA polymerase.
A
Early and middle T4 genes encode for proteins that modify the activity of sigma factors and host RNA polymerase to regulate the expression of T4 genes
16
Q
What would be the consequence of deleting the late T4 genes?
What would be the consequence of deleting the late T4 genes?
T4 capsid proteins would not be made.
T4 mRNA would not be produced.
ATP would not be produced and the T4 genome would not be packaged into the capsid.
The T4 genome would not be copied.
A
T4 capsid proteins would not be made.
17
Q
Although T4 encodes over 250 proteins, it does not encode its own RNA polymerase.
Although T4 encodes over 250 proteins, it does not encode its own RNA polymerase.
True
False
A
T
18
Q
The consequence of an infection by a temperate bacteriophage is that the bacterial cell
The consequence of an infection by a temperate bacteriophage is that the bacterial cell
may lyse before it divides or may continue to divide and replicate both the virus and the cell.
lyses before it gets a chance to divide.
never lyses but continues to divide and replicate both the virus and the cell.
divides faster at moderate temperatures.
A
may lyse before it divides or may continue to divide and replicate both the virus and the cell.
19
Q
The virus repressor protein
The virus repressor protein
controls both the lytic genes on the prophage and prevents an incoming virus of the same type.
does not control the prophage’s lytic genes but does control the incoming genomes of the same virus.
controls the prophage’s lytic genes but not the incoming genomes of the same virus.
has different actions in different situations
A
controls both the lytic genes on the prophage and prevents an incoming virus of the same type.
20
Q
Ch8 MC Q 13
A
deletion or inactivation of the cro gene
21
Q
A virus that kills its host is said to be
A virus that kills its host is said to be
temperate.
virulent or lysogenic, but not temperate.
lysogenic.
lytic or virulent.
A
lytic or virulent.
22
Q
Viruses can confer additional properties on their host cells, which can in turn be inherited.
Viruses can confer additional properties on their host cells, which can in turn be inherited.
True
False
A
T
23
Q
Temperate viruses can enter into either a lytic or lysogenic cycle.
Temperate viruses can enter into either a lytic or lysogenic cycle.
True
False
A
T
24
Q
How is penetration different in animal viruses as compared to bacterial viruses?
Hints
Hint 1.
[[viral penetration]] During the life cycle of any virus, once the virus has attached to the surface of the target cell, penetration must occur. Part of the viral particle or the entire particle must enter the target cell in order for viral replication to occur.
How is penetration different in animal viruses as compared to bacterial viruses?
The viral genome penetrates an animal cell, while the entire viral particle penetrates a bacterial cell.
There is no difference; only the viral genome penetrates both cell types.
The entire viral particle penetrates an animal cell, while only the viral genome penetrates a bacterial cell.
There is no difference; the entire viral particle penetrates both cell types.
A
The entire viral particle penetrates an animal cell, while only the viral genome penetrates a bacterial cell.
25
Differentiate between persistent and latent animal virus infections.
Hints
Hint 1.
[[animal virus infections]] Infection of an animal cell by a virus can lead to different results. Some viruses immediately replicate the virus and lead to viral release by cell destruction. Others keep the host cell alive for long periods of time while releasing new virus particles.
Differentiate between persistent and latent animal virus infections.
Persistent infections always lead to cell lysis, while latent infections never lead to cell lysis.
In a latent infection, the host cell is continually releasing new viral particles slowly. In a persistent infection, there are periods of time where the virus is not replicating and creating new viral particles.
In a persistent infection, the host cell is continually releasing new viral particles slowly. In a latent infection, there are periods of time where the virus is not replicating and creating new viral particles.
Persistent infections can cause transformation of the host cell, which can lead to the development of cancer. Latent infections do not cause transformation.
In a persistent infection, the host cell is continually releasing new viral particles slowly. In a latent infection, there are periods of time where the virus is not replicating and creating new viral particles.
26
Some viruses are associated with cancer. There are a variety of ways in which viruses may affect a cell in a way that may lead to cancer. Based on your knowledge of the life cycles of viruses and of molecular genetics, what is one way that this might happen?
Hints
Hint 1.
[[Molecular genetics of cancer]] Cancer develops when mutations occur that disrupt the normal regulation of the cell cycle. Based on what you know about the life cycles of viruses, how might a virus be associated with a mutation?
Some viruses are associated with cancer. There are a variety of ways in which viruses may affect a cell in a way that may lead to cancer. Based on your knowledge of the life cycles of viruses and of molecular genetics, what is one way that this might happen?
Viral genetic material inserts into a host genome, placing a promoter in a new location and turning on a gene that had previously been turned off.
Viral genetic material inserts into a host genome in a repetitive noncoding region.
Viral genetic material inserts into a host genome close to the termination sequence, far downstream of the promoter, and causes a silent mutation.
Viral genetic material inserts into a host genome and causes a mutation in a promoter, turning off a gene that had previously been turned on.
Viral genetic material inserts into a host genome, placing a promoter in a new location and turning on a gene that had previously been turned off.
27
Blocking polyomavirus SV40's ability to integrate its genome into host cells would
Blocking polyomavirus SV40's ability to integrate its genome into host cells would
increase the latent period of SV40.
increase the rate of transformation.
avoid cancer development from the virus.
switch SV40 into a lytic lifecycle which would be especially harmful to the host cells.
avoid cancer development from the virus.
28
Herpesviruses can cause all of the following diseases in humans EXCEPT
Herpesviruses can cause all of the following diseases in humans EXCEPT
chicken pox.
spongiform encephalopathy.
cancer.
cold sores.
spongiform encephalopathy.
29
```
Herpesviruses can cause __________.
Hints
Hint 1.
[[Herpesviruses]] Herpesviruses are double-stranded DNA viruses that have an envelope surrounding the viral capsid. These viruses can remain latent in the human body for long periods of time.
Herpesviruses can cause __________.
cancer
cold sores or fever blisters
shingles
All of the listed responses are correct.
```
All of the listed responses are correctTrue
30
```
Evolution is driven by
Evolution is driven by
random mutation.
selection pressure applied to random mutation.
novel metabolic pathways.
selection pressure.
```
selection pressure applied to random mutation.
31
According to the RNA world hypothesis, which of the following was the correct sequence of developments?
Hints
Hint 1.
[[RNA world hypothesis]] The RNA world hypothesis is a hypothesis that has been proposed to help explain the sequence of events that led to the origin of cellular life.
According to the RNA world hypothesis, which of the following was the correct sequence of developments?
biological building blocks (e.g., amino acids, sugars, and nucleosides), then RNA (including catalytic and self-replicating RNA), then protein synthesis, then DNA, then lipid bilayers surrounding early cellular life
biological building blocks (e.g., amino acids, sugars, and nucleosides), then lipid bilayers surrounding these building blocks, then RNA (including catalytic and self-replicating RNA), then protein synthesis, then DNA
biological building blocks (e.g., amino acids, sugars, and nucleosides), then DNA, then RNA (including catalytic and self-replicating RNA), then protein synthesis, then lipid bilayers surrounding early cellular life
biological building blocks (e.g., amino acids, sugars, and nucleosides), then RNA (including catalytic and self-replicating RNA), then DNA, then protein synthesis, then lipid bilayers surrounding early cellular life
biological building blocks (e.g., amino acids, sugars, and nucleosides), then RNA (including catalytic and self-replicating RNA), then protein synthesis, then DNA, then lipid bilayers surrounding early cellular life
32
What was the LUCA?
Hints
Hint 1.
[[Terminology]] LUCA stands for Last Universal Common Ancestor.
What was the LUCA?
the last eukaryote before eukaryotes diversified
the type of prokaryote that evolved into a eukaryote
the last organism prior to the divergence of bacteria and archaea
the first cellular organism to evolve
the last organism prior to the divergence of bacteria and archaea
33
LUCA is
LUCA is
actually somewhat of a misnomer because it is now believed that each of the domains arose independently.
the individual ancestor of each of the three domains.
the last universal common ancestor.
All of the answers are correct.
the last universal common ancestor.
34
Compared with today, the temperature on Earth during its first half-billion years was probably
Compared with today, the temperature on Earth during its first half-billion years was probably
considerably colder.
about the same as today on average, but the diurnal fluctuations were much greater.
considerably warmer.
about the same as today.
considerably warmer.
35
Microorganisms were probably restricted to the oceans and subsurface environments until
Microorganisms were probably restricted to the oceans and subsurface environments until
the ozone layer was made.
phototrophy evolved.
chemoorganotrophy developed.
aquatic life brought them onto land.
the ozone layer was made.
36
The first catalytic and self-replication biological molecule was most likely
The first catalytic and self-replication biological molecule was most likely
proteins.
ATP.
RNA.
DNA.
RNA.
37
The earliest nucleic acid was probably a simple DNA molecule.
The earliest nucleic acid was probably a simple DNA molecule.
True
False
False
38
The establishment of DNA as the genome of the cell may have resulted from the need to store genetic information in a more stable form than RNA.
The establishment of DNA as the genome of the cell may have resulted from the need to store genetic information in a more stable form than RNA.
True
False
True
39
When exposed to UV light, oxygen gas produces ozone gas.
When exposed to UV light, oxygen gas produces ozone gas.
True
False
True
40
The earliest stromatolites were probably formed by
The earliest stromatolites were probably formed by
anoxygenic lithotrophs.
oxygenic lithotrophs.
oxygenic phototrophs.
anoxygenic phototrophs.
anoxygenic phototrophs.
Stromatolites are layered mounds, columns, and sheet-like sedimentary rocks. They were originally formed by the growth of layer upon layer of cyanobacteria, a single-celled photosynthesizing microbe that lives today in a wide range of environments ranging from the shallow shelf to lakes, rivers, and even soils.
41
If there were photosynthetic organisms present when the earth was primarily anoxic, why was the development of cyanobacteria critical for the oxidation of the atmosphere?
Hints
Hint 1.
[[early earth]] The biochemical processes that were carried out on the early earth were all anaerobic. There was little or no oxygen available. In addition, the temperatures were thought to be very hot.
If there were photosynthetic organisms present when the earth was primarily anoxic, why was the development of cyanobacteria critical for the oxidation of the atmosphere?
The early forms of photosynthesis did produce oxygen, but it was not enough to make a difference in the atmosphere.
The early forms of photosynthesis were carried out in the water and there was no way for the oxygen to move into the atmosphere.
The early forms of photosynthesis did not produce oxygen as a waste product.
Cyanobacteria carry out anoxic photosynthesis.
The early forms of photosynthesis did not produce oxygen as a waste product.
42
It is hypothesized that early photosynthesis was anoxygenic. If so, what was the effect of the appearance of organisms using oxygenic photosynthesis?
Hints
Hint 1.
[[Anoxygenic]] "Anoxygenic" means without generating oxygen.
It is hypothesized that early photosynthesis was anoxygenic. If so, what was the effect of the appearance of organisms using oxygenic photosynthesis?
The increase in organisms using oxygenic photosynthesis led to an increased ability to use solar radiation.
The increase in organisms using oxygenic photosynthesis led to a decrease in the diversity of organisms as they outcompeted organisms using anoxygenic photosynthesis.
Organisms using oxygenic photosynthesis release oxygen into the atmosphere, causing an increase in the oxygen in the atmosphere and allowing for the development of aerobes.
The increase in oxygen in the atmosphere from organisms using oxygenic photosynthesis caused a great decrease in diversity as obligate aerobes were killed.
Organisms using oxygenic photosynthesis release oxygen into the atmosphere, causing an increase in the oxygen in the atmosphere and allowing for the development of aerobes.
43
It is hypothesized that early photosynthesis was anoxygenic. Think about the role of oxygen in photosynthesis as carried out by green plants, green algae, and cyanobacteria (as opposed to modern organisms that use anoxygenic photosynthesis). What would have been different in anoxygenic photosynthesis (or is different in modern organisms that use anoxygenic photosynthesis)?
Hints
Hint 1.
[[Anoxygenic]] "Anoxygenic" means without generating oxygen.
It is hypothesized that early photosynthesis was anoxygenic. Think about the role of oxygen in photosynthesis as carried out by green plants, green algae, and cyanobacteria (as opposed to modern organisms that use anoxygenic photosynthesis). What would have been different in anoxygenic photosynthesis (or is different in modern organisms that use anoxygenic photosynthesis)?
Anoxygenic organisms would not have been able to produce ATP, only NADPH.
Anoxygenic organisms do not require light while oxygenic organisms do require light.
Anoxygenic organisms would have been able to produce only NADPH, not ATP.
Green plants, green algae, and cyanobacteria split H2O to replace an excited electron in noncyclic photophosphorylation. Oxygen is released into the atmosphere. In anoxygenic photosynthesis, a different molecule (such as H2S) is split and a different product (such as sulfur) is released.
Green plants, green algae, and cyanobacteria split H2O to replace an excited electron in noncyclic photophosphorylation. Oxygen is released into the atmosphere. In anoxygenic photosynthesis, a different molecule (such as H2S) is split and a different product (such as sulfur) is released.
44
It is believed that phototrophy arose approximately 3.3 billion years ago in
It is believed that phototrophy arose approximately 3.3 billion years ago in
LUCA.
Bacteria.
Archaea.
Eukarya.
Bacteria
45
As oxygen appeared in the atmosphere, ________ also accumulated, which formed a protective barrier that protects the Earth from ________.
As oxygen appeared in the atmosphere, ________ also accumulated, which formed a protective barrier that protects the Earth from ________.
sulfate / hydrogen sulfide
elemental sulfur / volcanism
ozone / UV radiation
ferrous iron / hydroxylating radicals
ozone / UV radiation
46
Eukaryotes originated after the rise in atmospheric oxygen.
Eukaryotes originated after the rise in atmospheric oxygen.
True
False
True
47
Oxygen was a driving factor in the formation of eukaryotic cells.
Oxygen was a driving factor in the formation of eukaryotic cells.
True
False
True
48
Which of the following statements is FALSE concerning the universal tree of life?
Which of the following statements is FALSE concerning the universal tree of life?
Previous versions of the universal tree of life were based largely on fossils and comparative biology, which overlooked the diversity of and relationships between most prokaryotes.
The current universal tree of life depicts three domains of life, two of which are prokaryotic.
The current universal tree of life is based on molecular sequences and completely changes our view of evolutionary relationships between eukaryotic species.
The current universal tree of life is supported by multiple genes including SSU rRNA sequences.
The current universal tree of life is based on molecular sequences and completely changes our view of evolutionary relationships between eukaryotic species.
49
The evolutionary history of a group of organisms is called its ________ and it is inferred from ________.
The evolutionary history of a group of organisms is called its ________ and it is inferred from ________.
phylogeny / nucleotide sequence data
phylogeny / phenotype
taxonomy / phenotype
taxonomy / morphology
phylogeny / nucleotide sequence data
50
What characteristics make a gene a good candidate for determining the evolutionary relationships between organisms?
What characteristics make a gene a good candidate for determining the evolutionary relationships between organisms?
highly conserved and universally distributed
universally distributed
transferred horizontally between species
highly conserved
highly conserved and universally distributed
51
Sequencing technology and molecular phylogenetic analyses have had very little impact on our understanding of the evolution and diversity of life on Earth.
Sequencing technology and molecular phylogenetic analyses have had very little impact on our understanding of the evolution and diversity of life on Earth.
True
False
False
52
The primary domains were founded based on comparative ribosomal RNA gene sequencing.
The primary domains were founded based on comparative ribosomal RNA gene sequencing.
True
False
True
53
Approximately 4 billion years ago Archaea and Bacteria diverged as being distinct from each other.
Approximately 4 billion years ago Archaea and Bacteria diverged as being distinct from each other.
True
False
True
54
Based on the phylogenetic tree below, which of the following statements is FALSE?
Based on the phylogenetic tree below, which of the following statements is FALSE?
Species C is more closely related to species B than to species D.
Species F is more closely related to species D than to species E.
Species D is more closely related to species C than to species E.
Species E is more closely related to species A than to species D.
Species D is more closely related to species C than to species E.
55
The most widely used molecule in sequence-based evolutionary analyses are ________ genes.
The most widely used molecule in sequence-based evolutionary analyses are ________ genes.
ATPase
SSU rRNA
electron transport
tRNA
SSU rRNA
56
Systematic analysis now commonly includes ________ to identify, characterize, and determine relationships between new strains of bacterial species.
Systematic analysis now commonly includes ________ to identify, characterize, and determine relationships between new strains of bacterial species.
pigments
staining
microscopy
whole genome analysis
whole genome analysis
57
In taxonomy, family is a more general term than order.
In taxonomy, family is a more general term than order.
True
False
False
58
Chemolithotrophs that obtain electrons from donors such as sulfide use the same electron transport chains to obtain energy as chemoorganotrophs.
Chemolithotrophs that obtain electrons from donors such as sulfide use the same electron transport chains to obtain energy as chemoorganotrophs.
True
False
True
59
What metabolism would be favored when there is a lack of electron acceptors?
What metabolism would be favored when there is a lack of electron acceptors?
anoxic ammonia oxidation
anaerobic fermentation
anoxygenic photosynthesis
acetogenesis
anaerobic fermentation
60
Some anaerobic bacteria not only use organic compounds as a carbon source but can also use them for energy as well.
Some anaerobic bacteria not only use organic compounds as a carbon source but can also use them for energy as well.
True
False
True
61
Fermentation of organic compounds, such as acetate, produces NADH and ATP.
Fermentation of organic compounds, such as acetate, produces NADH and ATP.
True
False
False
62
Which of the following is a similarity between Archaea and Eukarya?
Hints
Hint 1.
[[Domains]] At first glance, Archaea seem to look similar to Bacteria. However, they are more similar to Eukarya than to Bacteria in several important ways.
Which of the following is a similarity between Archaea and Eukarya?
Their cell membranes are the same.
Their DNA is complexed with histones.
They both have peptidoglycan.
They have identical RNA polymerases.
Their DNA is complexed with histones.
63
Some Archaea live in remarkably saline environments. What is the challenge of living in a highly saline environment?
Hints
Hint 1.
[[Osmosis]] Osmosis is the diffusion of water across a semipermeable membrane.
Some Archaea live in remarkably saline environments. What is the challenge of living in a highly saline environment?
In a highly saline environment, most cells desiccate. Extreme halophiles have specialized adaptations to prevent desiccation.
The high salt concentration will damage the cell wall and cause it to burst.
The high salt concentration will cause water to flow into the cell until it lyses.
In extremely saline environments, salt will move into most cells through diffusion. Because of the influx of salt, the ionic balance within the cell will be disrupted.
In a highly saline environment, most cells desiccate. Extreme halophiles have specialized adaptations to prevent desiccation.
64
Archaea is divided into three phyla.
Archaea is divided into three phyla.
True
False
False
65
Thus far, only Archaea have been found in the salt lakes, while Bacteria and Eukarya are noticeably absent.
Thus far, only Archaea have been found in the salt lakes, while Bacteria and Eukarya are noticeably absent.
True
False
False
66
Halophilic Archaea are the only inhabitants of highly saline environments.
Halophilic Archaea are the only inhabitants of highly saline environments.
True
False
False
67
Methanogens
Methanogens
produce, utilize, and detoxify methane.
produce methane as a part of their energy metabolism.
utilize methane as an energy source.
process and store methane to detoxify it.
produce methane as a part of their energy metabolism.
68
The cell walls of methanogens can consist of __________.
Hints
Hint 1.
[[methanogens]] Methanogens are obligate anaerobes that produce methane. They have a diversity of morphologies within these genera.
The cell walls of methanogens can consist of __________.
S-layer
pseudomurein
methanochondroitin
all of the listed materials
all of the listed materials
69
Though the known diversity of acetotrophic methanogens is low, they are ecologically significant in nature.
Though the known diversity of acetotrophic methanogens is low, they are ecologically significant in nature.
True
False
True
70
The microorganisms that are thought to resemble the first cellular forms of life on Earth are
The microorganisms that are thought to resemble the first cellular forms of life on Earth are
the Nanoarchaeota.
acidophilic Archaea.
fermentative thermophiles.
H2-oxidizing hyperthermophiles.
H2-oxidizing hyperthermophiles.
71
There is a class of cells that are thought to be the closest evolutionarily related cells to the first cells on Earth. Which class and the listed justification are correct?
Hints
Hint 1.
[[microbial evolution]] Early Earth is thought to have been an anoxic environment with extreme temperatures. Very few organisms would have been able to survive and reproduce under these conditions.
There is a class of cells that are thought to be the closest evolutionarily related cells to the first cells on Earth. Which class and the listed justification are correct?
hyperthermophiles; similar metabolism
hyperthermophiles; similar phenotype
halophiles; similar metabolism
halophiles; similar habitat
hyperthermophiles; similar metabolism
72
Some Archaea are chemoorganotrophs and use organic compounds as electron donors for energy metabolism.
Some Archaea are chemoorganotrophs and use organic compounds as electron donors for energy metabolism.
True
False
True
73
Bacteria will become part of a biofilm because __________.
Hints
Hint 1.
[[biofilms]] Biofilms contain multiple layers of cells held together by a sticky matrix. Once formation begins, signals are sent out to recruit other cells to join the biofilm.
Bacteria will become part of a biofilm because __________.
It allows them to be phagocytosed easier.
It allows them to live separated from other bacteria.
It allows them to remain in a favorable niche.
It allows all compounds in the environment to diffuse to the organism's location much faster.
It allows them to remain in a favorable niche.
74
Characteristics of biofilms include __________.
Hints
Hint 1.
[[biofilms]] Bacteria can colonize any surface and, once colonized, a biofilm can develop. Biofilms are very beneficial to bacteria.
Characteristics of biofilms include __________.
They are a single layer of cells.
the presence of a cellulose matrix to hold the organisms together
the presence of one or more species of bacteria
They do not have to be attached to a surface.
the presence of one or more species of bacteria
75
Which of the following is an example of a biofilm?
Which of the following is an example of a biofilm?
marine diatom
soap scum
dental plaque
planktonic microcolony
dental plaque
76
__________.
Hints
Hint 1.
[[Biofilms in nature]] Many organisms are capable of forming biofilms on surfaces as an adaptation for survival.
All of the following are true of biofilms EXCEPT that __________.
biofilm formation and dispersal are regulated processes
biofilms are always composed of only one species at a time
biofilms form on virtually all submerged surfaces in nature
biofilms protect organisms from antibiotics
biofilms are always composed of only one species at a time
77
Cells within a biofilm excrete an adhesive matrix primarily composed of ________ but can also contain nucleic acids as well as proteins.
Cells within a biofilm excrete an adhesive matrix primarily composed of ________ but can also contain nucleic acids as well as proteins.
fatty acids
polysaccharides
monomers
lipids
polysaccharides
78
The cells within a biofilm can undergo intra-species signaling; however, inter-species signaling does not occur.
The cells within a biofilm can undergo intra-species signaling; however, inter-species signaling does not occur.
True
False
False
79
Chocolate agar is an example of a ________ medium.
Chocolate agar is an example of a ________ medium.
differential
selective
general-purpose
selective and differential
general-purpose
80
The component that enriches chocolate agar is
The component that enriches chocolate agar is
heat-lysed blood cells.
methyl brown indicator dye.
chocolate.
None of the answers are correct.
heat-lysed blood cells.
81
Which type of medium typically contains an indicator dye?
Which type of medium typically contains an indicator dye?
differential but not selective
selective but not differential
both selective and differential
neither selective nor differential
differential but not selective
82
MacConkey agar and eosin-methylene blue (EMB) agar are ________ media.
MacConkey agar and eosin-methylene blue (EMB) agar are ________ media.
differential but not selective
selective but not differential
both selective and differential
neither selective nor differential
both selective and differential
83
In cases of suspected foodborne or waterborne infections, fecal samples should be inoculated into a variety of selective media.
In cases of suspected foodborne or waterborne infections, fecal samples should be inoculated into a variety of selective media.
True
False
True
84
Many pathogens can be readily grown in laboratory culture.
Many pathogens can be readily grown in laboratory culture.
True
False
True
85
Immunoassays are techniques that use immunology to determine the presence of antigens, antibodies, or both. In one type of enzyme-linked immunoassay test, antibodies are attached to a matrix (such as the bottom of a microtiter plate). Next, the sample to be tested (such as patient serum) is added. An antibody-enzyme complex is then added. Finally, the enzyme substrate is added. The enzyme must catalyze a reaction that is visible (such as a color change), meaning that it is possible to see if the antibodies were present by seeing if there is a color change. The development of the colored product is proportional to the concentration of antibody. What would this sort of test be useful for?
Hints
Hint 1.
[[Immunoassays]] Immunoassays involve testing using antigen-antibody reactions. Consider that the process was started with an antibody that was bound to the matrix.
Immunoassays are techniques that use immunology to determine the presence of antigens, antibodies, or both. In one type of enzyme-linked immunoassay test, antibodies are attached to a matrix (such as the bottom of a microtiter plate). Next, the sample to be tested (such as patient serum) is added. An antibody-enzyme complex is then added. Finally, the enzyme substrate is added. The enzyme must catalyze a reaction that is visible (such as a color change), meaning that it is possible to see if the antibodies were present by seeing if there is a color change. The development of the colored product is proportional to the concentration of antibody. What would this sort of test be useful for?
It would be useful for detecting whether a patient had antibodies for a particular pathogen. The second antibody (attached to the enzyme) is able to bind because it is specific for the antigen.
It would be useful for detecting whether a patient had antibodies for a particular antigen. The second antibody (attached to the enzyme) is not necessary as the enzyme can react directly with the antigen if the antigen is present.
It would be useful for detecting a virus in a patient's blood, as the antibody on the matrix would bind to the virus. The second antibody (attached to the enzyme) is able to bind because it is specific for the first antibody.
It would be useful for detecting a virus in a patient's blood, as the antibody on the matrix would bind to the virus. The second antibody (attached to the enzyme) is able to bind because it is specific for the antigen.
It would be useful for detecting a virus in a patient's blood, as the antibody on the matrix would bind to the virus. The second antibody (attached to the enzyme) is able to bind because it is specific for the antigen.
If the second antibody bound to the first antibody, then it would always bind and the concentration would reflect the amount of antibody initially plated on the matrix.The patient's sample might contain antibodies, but those would not be able to bind to the antibody initially on the matrix.
86
```
Indirect ELISA is used to detect
Indirect ELISA is used to detect
antibodies.
antigens.
viruses.
serum.
```
antibodies.
87
The ELISA test for HIV infection is a direct test for HIV envelope proteins.
The ELISA test for HIV infection is a direct test for HIV envelope proteins.
True
False
The ELISA test for HIV infection is a direct test for HIV envelope proteins.
The ELISA test for HIV infection is a direct test for HIV envelope proteins.
True
False
88
One problem with the EIA test is the disposal of radioactive wastes.
One problem with the EIA test is the disposal of radioactive wastes.
True
False
False
An enzyme-linked immunosorbent assay, also called ELISA or EIA, is a test that detects and measures antibodies in your blood. This test can be used to determine if you have antibodies related to certain infectious conditions
89
Identification of a pathogen in a patient can be done without having to culture the pathogen using __________.
Hints
Hint 1.
[[nucleic acid amplification]] PCR (polymerase chain reaction) is the process of making many copies of a specific DNA sequence. PCR based tests are available for a number of pathogens.
Identification of a pathogen in a patient can be done without having to culture the pathogen using __________.
PCR testing if a pathogen specific genetic sequence is not known
none of the listed responses are correct
PCR testing if a host specific genetic sequence is known
PCR testing if growing the pathogen in the lab is common
none of the listed responses are correct
PCR cannot be performed if there is not a pathogen specific gene sequence.A host specific gene sequence is not needed for PCR identification of pathogensIf it were common to grow the pathogen in the lab, PCR identification would not be necessary.
90
Why is a special polymerase, such as Taq polymerase, used for PCR?
Hints
Hint 1.
[[PCR]] Polymerase chain reaction is used to amplify DNA (in other words, to make many copies of DNA).
Why is a special polymerase, such as Taq polymerase, used for PCR?
It has exceptionally good proofreading ability.
It is able to add DNA nucleotides without requiring an existing strand to add on to.
It can add both DNA and RNA nucleotides.
It works at relatively high temperatures.
It works at relatively high temperatures.
Taq polymerase is a DNA dependent DNA polymerase, meaning that is makes DNA from a DNA template
Like other DNA polymerases, Taq polymerase requires a primer in order to add DNA nucleotides.
Taq polymerase actually lacks proofreading ability, making it more error-prone than other DNA polymerases.
91
Influenza vaccines do NOT provide lifelong immunity on account of __________.
Hints
Hint 1.
[[influenza]] Influenza is caused by a negative-sense RNA virus. Of the three classes of influenza viruses (A, B, and C), class A is the most important human pathogen.
Influenza vaccines do NOT provide lifelong immunity on account of __________.
antigenic drift in the neuraminidase and hemagglutinin proteins
antigenic drift in the protein coat of the influenza virus
antigenic shift in the neuraminidase and hemagglutinin proteins
antigenic shift in the protein coat of the influenza virus
antigenic drift in the neuraminidase and hemagglutinin proteins
Antigenic drift does not involve the viral capsid proteins.
92
Influenza A virus can be identified by which of the following surface glycoproteins?
Influenza A virus can be identified by which of the following surface glycoproteins?
M protein
HA
both HA and NA
NA
both HA and NA
93
More than one type of influenza virus can infect a given cell at a given time.
More than one type of influenza virus can infect a given cell at a given time.
True
False
True
94
The influenza viral envelope is unique because it contains only one type of protein.
The influenza viral envelope is unique because it contains only one type of protein.
True
False
False
95
Reassortment of the genes of the influenza virus is facilitated by the fact that the genome is segmented.
Reassortment of the genes of the influenza virus is facilitated by the fact that the genome is segmented.
True
False
True
96
Which of the following statements is TRUE about HIV infections?
Which of the following statements is TRUE about HIV infections?
The viral nucleocapsid of the virus enters the host cell when the viral and host membranes fuse.
T-helper cells are greatly reduced in number.
The cDNA can integrate into the host chromosome.
All of these statements are true.
All of these statements are true.
97
Amphotericin B is an antifungal medication. What might its mechanism of action be?
Hints
Hint 1.
[[Choosing effective medications]] The best medications are those that target structures found in the pathogen but not found in human cells. What types of cells do fungi have? How are these cells similar to and different from those of humans?
Amphotericin B is an antifungal medication. What might its mechanism of action be?
It binds to phospholipids in fungal membranes.
It binds to ergosterol.
It binds to ribosomes.
It prevents synthesis of peptidoglycan cell walls
It binds to ergosterol.
The phospholipids in fungal membranes are similar to those of other eukaryotes, including humans. When treatments target a structure common to both pathogenic and human cells, they increase the risk of severe side effects.
However, peptidoglycan is found in bacterial cell walls, not fungal cell walls.
98
Which fungal genus is correctly matched to the class of disease it causes?
Hints
Hint 1.
[[medically important fungi]] Fungal diseases are called mycoses. These diseases can range from superficial infections to life-threatening systemic infections.
Which fungal genus is correctly matched to the class of disease it causes?
systemic mycosis: Sporothrix
subcutaneous mycosis: Microsporum
superficial mycosis: Aspergillus
systemic mycosis: Candida
systemic mycosis: Candida
99
Azole medications inhibit the production of ergosterols. Which infection would they be most effective against?
Hints
Hint 1.
[[Terminology]] Ergosterols are found in cell membranes.
Azole medications inhibit the production of ergosterols. Which infection would they be most effective against?
a tapeworm
malaria
a ringworm infection of the scalp
a bacterial infection
a ringworm infection of the scalp
Bacteria do not have ergosterols in their cell membranes
Malaria is caused by Plasmodium vivax, a protist. Protists do not have ergosterols in their cell membranesTapeworms do not have ergosterols in their cell membranes.
100
```
Which of these organisms has hyphae?
Hints
Hint 1.
[[Terminology]] Hyphae are filamentous structures.
Which of these organisms has hyphae?
a bread mold
an amoeboid protozoan
a Staphylococcus aureus bacterium
rotifers
```
a bread mold
| Hyphae are not typical of protozoa.Staphylococcus bacteria form grapelike clusters of spherical cells.
101
Fungi that can grow in a yeast or a mold form depending on the conditions are termed __________.
Hints
Hint 1.
[[medically important fungi]] Fungi can be unicellular yeast or multicellular molds. Most fungi are non-pathogenic to humans; however, a few fungi are capable of causing serious human illness.
Fungi that can grow in a yeast or a mold form depending on the conditions are termed __________.
pleomorphic
dimorphic
amphimorphic
morphic
dimorphic
102
ALL fungal infections can broadly be termed
ALL fungal infections can broadly be termed
superficial.
benign.
systemic.
mycoses.
mycoses.
103
What is the term used for the filamentous body found in many fungal species?
Hints
Hint 1.
[[Fungi]] One distinguishing characteristic of fungi is that many have a unique filamentous body structure consisting of hyphae.
What is the term used for the filamentous body found in many fungal species?
dikaryote
protonema
mycelium
gametophyte
mycelium
104
Which of the following is MOST likely to cause an infection in HIV/AIDS patients?
Which of the following is MOST likely to cause an infection in HIV/AIDS patients?
Schistosoma mansoni
Leishmania tropica
Candida albicans
Giardia intestinalis
Candida albicans
105
The MOST serious types of fungal infections are
The MOST serious types of fungal infections are
mycotoxic infections.
superficial mycoses.
subcutaneous infections.
systemic mycoses.
systemic mycoses.
106
The most common method of contracting a systemic mycosis is through __________.
Hints
Hint 1.
[[mycoses]] Systemic mycoses are the most serious of the fungal infections. In these cases, the fungi grow within the patient, causing damage and affecting multiple organ systems.
The most common method of contracting a systemic mycosis is through __________.
ingestion
sexual contact
person-to-person contact
inhalation
inhalation
Stomach acid would destroy fungal spores that are ingested.Fungi that cause systemic infections are most commonly found in soil.
107
Which of the following is considered an opportunistic pathogen?
Which of the following is considered an opportunistic pathogen?
Toxoplasma gondii
Candida albicans
Plasmodium vivax
Trichomoniasis vaginalis
Candida albicans
108
Which of the following is an example of a secondary systemic mycosis?
Hints
Hint 1.
[[Terminology]] A mycosis is a fungal infection.
Which of the following is an example of a secondary systemic mycosis?
a Staphylococcus aureus infection on the surface of the skin
amoebic dystentery, a gastrointestinal illness
a ringworm infection of the scalp
cryptococcosis that develops in the lungs of a patient with HIV/AIDS
cryptococcosis that develops in the lungs of a patient with HIV/AIDS
Amoeibic dysentery is systemic, but it is not a mycosis.
109
Superficial mycoses are caused by a group of fungal pathogens called __________.
Hints
Hint 1.
[[mycoses]] Superficial mycoses are very common. Flaky skin, itching, and redness characterize these types of fungal infections.
Superficial mycoses are caused by a group of fungal pathogens called __________.
dermatophytes
dermatologic
dematiaceous
dimorphic
dermatophytes
110
```
Athlete's foot is an example of a
Athlete's foot is an example of a
superficial parasitic infection.
hypersensitivity reaction.
superficial fungal infection.
protozoal infection.
```
superficial fungal infection.
111
Many fungi produce ________ that can cause significant disease.
Many fungi produce ________ that can cause significant disease.
mycotoxins
cellulases
endotoxins
chitinases
mycotoxins
112
Systemic fungal infections are difficult to treat because active antifungal drugs cause significant host toxicity.
Systemic fungal infections are difficult to treat because active antifungal drugs cause significant host toxicity.
True
False
True
113
Counting chambers are used for estimating the number of cells present in a liquid culture.
Counting chambers are used for estimating the number of cells present in a liquid culture.
True
False
True
