Portage Learning BIOD 171 LAB 6 EXAM Question
With Answer NEW UPDATE YEAR 2025 UPGRADED
TO 2026 RATED A+AND FIVE STARS
True or False: viruses can be classified as prokaryotic or
eukaryotic - 100 correct answer as-False. Viruses are
neither prokaryotic or eukaryotic
What is an obligate intracellular parasite? - 100 correct
answer as-viruses cannot replicate unless inside a living host
cell. As a parasite, a virus depends on its living host to provide the
framework (proteins, etc) to replicate—to make additional copies
of itself.
What is a viral capsid? - 100 correct answer as-a
membrane-like protective structure that contains genetic material
similar to nucleus of eukaryotic cells.
What is the viral envelope, and what does the presence (or
absence) of it tell you about the type of virus? - 100 correct
answer as-The envelope surrounds the viral capsid, is derived
from the host cell membrane and serves as an additional barrier
to the external environment. The overwhelming majority of animal
viruses are enveloped whereas the majority of plant or bacteria-
infecting viruses are not.
What type of microscope would be used to study the shape of a
viral capsid? - 100 correct answer as-Due to its size (~30-
150 nm) most viral capsids must be visualized via electron
microscopy.
,How does the viral envelope both aid in cell entry as well as hide
it from being detected by the immune system? - 100 correct
answer as-The viral envelope contains the necessary proteins
required for interaction with host cells. As the envelope is derived
from the host cell membrane, this camouflages the virus and
lowers the likelihood of immune detection by making it appear
similar to the normal biological host cell.
What must happen before viral replication of its genome can
occur? - 100 correct answer as-For all viruses, the genome
is replicated following attachment and entry, never before.
Describe the basic steps of the viral life cycle. - 100 correct
answer as-1. Attachment: Viral receptors bind to host proteins
on the surface of the cell.2. Entry: The virus fuses with the host
membrane and enters the cell3. Uncoating: (where applicable) the
viral capsid disassembles4. Replication: The viral genome
provides the 'blueprint' to make copies of itself5. Exit: New viruses
are produced and leave the cell6. New infection: Newly produced
viruses leave the host cell and go on to infect new cells. The
process outlined above now restarts.
What is a bacteriophage? - 100 correct answer as-A virus
that infects bacteria
What structural aspects make bacteriophages distinct from
viruses that infect either animals or plants? - 100 correct
answer as-Bacteriophages possess an icosahedral capsid
head group and a helical tail. Attached to the tail are fibrous
extensions or 'legs' that aid in binding host cells. Notably, this
particular structural arrangement has not been observed among
viruses that infect either animals or plants.
,Which viral replicative process results in the destruction of the
host cell? - 100 correct answer as-The lytic replication cycle
occurs when a bacteriophage replicates within a host until it
ruptures, effectively destroying the host bacterial cell. The phrase
lytic stems from 'lysis', meaning to rupture or disintegrate
(breakdown) a cell.
Describe the appearance of a bacterial culture infected with virus
at the time of infection versus later once viral replication is
occurring at a high rate. - 100 correct answer as-During the
initial inoculation of virus and bacteria, the media has a high
degree of turbidity (cloudiness). However, as the lytic cycle
progresses and more and more bacterial cells are destroyed, the
culture media turns from turbid to clear, as turbidity is a function of
the number of intact bacterial cells present in the media. Thus, as
bacterial cell numbers decrease due to lysis, the media becomes
clearer.
To what family of viruses does rubella come from and how is it
transmitted? - 100 correct answer as-Rubella virus belongs
to a family of viruses called Togaviridae. Rubella is transmitted via
air-borne particles such as when a person coughs.
What is the common name for rubeola, and is it a DNA or RNA
virus? - 100 correct answer as-Rubeola is commonly
referred to as the measles and belongs to the family of viruses
called Paramyxovirus. Rubeola viruses are RNA viruses with a
genome ~ 15,000 nucleotides long.
What disease state emerges as a viral reactivation of a prior
infection with the varicella virus? - 100 correct answer as-
Shingles, also known as Herpes zoster, is due to the reactivation
of the varicella-zoster virus (VZV). Because VZV lies dormant in
inactive nerve cells, its reactivation typically results in painful
, blisters. However, unlike the initial chickenpox rash, the blisters
are localized and limited to small areas.
What linear, double-stranded, enveloped DNA virus is the first
virus (as of October 26, 1977) to be declared eradicated? - 100
correct answer as-Although once a major cause of death in
the world, a smallpox vaccine was developed in 1796 by Edward
Jenner. Global vaccination efforts have prevented smallpox from
appearing in humans since October 26, 1977, making smallpox
the first infectious disease ever to be eradicated.
What are the two key glycoproteins found in the influenza virus? -
100 correct answer as-The viral envelope contains two key
glycoproteins, hemagglutinins (HA) and neuraminidase (N).
Hemagglutinins are heavily involved in the entry of the viral
particle into a host cell, while neuraminidase proteins are involved
in the budding and release of new viral particles from the host
cell.
Describe the composition of HIV. - 100 correct answer as-
HIV contains two copies of single-stranded, linear RNA that is
enclosed by a capsid. The conical capsid surrounds the two RNA
strands and is comprised of ~2,000 copies of the viral protein p24.
A viral envelope derived from the cell host membrane then
surrounds the viral capsid. Within this envelope are two key
glycoproteins, gp120 and gp41, which are essential for viral
binding and entry into the host cell.
What are the 2 basic components of a virus? - 100 correct
answer as-1)genomic material comprised of DNA or RNA
2)capsid membrane-like protective structure that contains genetic
material similar to nucleus of eukaryotic cells.
With Answer NEW UPDATE YEAR 2025 UPGRADED
TO 2026 RATED A+AND FIVE STARS
True or False: viruses can be classified as prokaryotic or
eukaryotic - 100 correct answer as-False. Viruses are
neither prokaryotic or eukaryotic
What is an obligate intracellular parasite? - 100 correct
answer as-viruses cannot replicate unless inside a living host
cell. As a parasite, a virus depends on its living host to provide the
framework (proteins, etc) to replicate—to make additional copies
of itself.
What is a viral capsid? - 100 correct answer as-a
membrane-like protective structure that contains genetic material
similar to nucleus of eukaryotic cells.
What is the viral envelope, and what does the presence (or
absence) of it tell you about the type of virus? - 100 correct
answer as-The envelope surrounds the viral capsid, is derived
from the host cell membrane and serves as an additional barrier
to the external environment. The overwhelming majority of animal
viruses are enveloped whereas the majority of plant or bacteria-
infecting viruses are not.
What type of microscope would be used to study the shape of a
viral capsid? - 100 correct answer as-Due to its size (~30-
150 nm) most viral capsids must be visualized via electron
microscopy.
,How does the viral envelope both aid in cell entry as well as hide
it from being detected by the immune system? - 100 correct
answer as-The viral envelope contains the necessary proteins
required for interaction with host cells. As the envelope is derived
from the host cell membrane, this camouflages the virus and
lowers the likelihood of immune detection by making it appear
similar to the normal biological host cell.
What must happen before viral replication of its genome can
occur? - 100 correct answer as-For all viruses, the genome
is replicated following attachment and entry, never before.
Describe the basic steps of the viral life cycle. - 100 correct
answer as-1. Attachment: Viral receptors bind to host proteins
on the surface of the cell.2. Entry: The virus fuses with the host
membrane and enters the cell3. Uncoating: (where applicable) the
viral capsid disassembles4. Replication: The viral genome
provides the 'blueprint' to make copies of itself5. Exit: New viruses
are produced and leave the cell6. New infection: Newly produced
viruses leave the host cell and go on to infect new cells. The
process outlined above now restarts.
What is a bacteriophage? - 100 correct answer as-A virus
that infects bacteria
What structural aspects make bacteriophages distinct from
viruses that infect either animals or plants? - 100 correct
answer as-Bacteriophages possess an icosahedral capsid
head group and a helical tail. Attached to the tail are fibrous
extensions or 'legs' that aid in binding host cells. Notably, this
particular structural arrangement has not been observed among
viruses that infect either animals or plants.
,Which viral replicative process results in the destruction of the
host cell? - 100 correct answer as-The lytic replication cycle
occurs when a bacteriophage replicates within a host until it
ruptures, effectively destroying the host bacterial cell. The phrase
lytic stems from 'lysis', meaning to rupture or disintegrate
(breakdown) a cell.
Describe the appearance of a bacterial culture infected with virus
at the time of infection versus later once viral replication is
occurring at a high rate. - 100 correct answer as-During the
initial inoculation of virus and bacteria, the media has a high
degree of turbidity (cloudiness). However, as the lytic cycle
progresses and more and more bacterial cells are destroyed, the
culture media turns from turbid to clear, as turbidity is a function of
the number of intact bacterial cells present in the media. Thus, as
bacterial cell numbers decrease due to lysis, the media becomes
clearer.
To what family of viruses does rubella come from and how is it
transmitted? - 100 correct answer as-Rubella virus belongs
to a family of viruses called Togaviridae. Rubella is transmitted via
air-borne particles such as when a person coughs.
What is the common name for rubeola, and is it a DNA or RNA
virus? - 100 correct answer as-Rubeola is commonly
referred to as the measles and belongs to the family of viruses
called Paramyxovirus. Rubeola viruses are RNA viruses with a
genome ~ 15,000 nucleotides long.
What disease state emerges as a viral reactivation of a prior
infection with the varicella virus? - 100 correct answer as-
Shingles, also known as Herpes zoster, is due to the reactivation
of the varicella-zoster virus (VZV). Because VZV lies dormant in
inactive nerve cells, its reactivation typically results in painful
, blisters. However, unlike the initial chickenpox rash, the blisters
are localized and limited to small areas.
What linear, double-stranded, enveloped DNA virus is the first
virus (as of October 26, 1977) to be declared eradicated? - 100
correct answer as-Although once a major cause of death in
the world, a smallpox vaccine was developed in 1796 by Edward
Jenner. Global vaccination efforts have prevented smallpox from
appearing in humans since October 26, 1977, making smallpox
the first infectious disease ever to be eradicated.
What are the two key glycoproteins found in the influenza virus? -
100 correct answer as-The viral envelope contains two key
glycoproteins, hemagglutinins (HA) and neuraminidase (N).
Hemagglutinins are heavily involved in the entry of the viral
particle into a host cell, while neuraminidase proteins are involved
in the budding and release of new viral particles from the host
cell.
Describe the composition of HIV. - 100 correct answer as-
HIV contains two copies of single-stranded, linear RNA that is
enclosed by a capsid. The conical capsid surrounds the two RNA
strands and is comprised of ~2,000 copies of the viral protein p24.
A viral envelope derived from the cell host membrane then
surrounds the viral capsid. Within this envelope are two key
glycoproteins, gp120 and gp41, which are essential for viral
binding and entry into the host cell.
What are the 2 basic components of a virus? - 100 correct
answer as-1)genomic material comprised of DNA or RNA
2)capsid membrane-like protective structure that contains genetic
material similar to nucleus of eukaryotic cells.
