chapter 6
How does bacteriophage nucleic acid enter the host cell?
Injection
True or false: Embryonic tissue can serve as a primary cell line for viral culture.
True
True or false: Viral nucleic acid may be single-stranded or double-stranded DNA or RNA.
True
A single virus particle is known as a(n)
Virion
The process of_____________ , a type of penetration, occurs when viruses are taken into the cell followed by engulfment in a vacuole or vesicle.
endocytosis or phagocytosis
Which term is used to describe the process when a virus is engulfed by a cell in a vacuole or vesicle?
endocytosis.
A(n)_______ virus has a membranous layer external to the nucleocapsid.
enveloped
Budding is a type of ______ process where enveloped viruses are released from the host cell membrane.
exocytic
True or false: Chicken eggs have a monolayer of cells within them which offer a good place to propagate virus.
false
The membrane receptors that viruses attach to during adsorption are typically composed of ______.
glycoproteins
Viral transformation implies ______.
host DNA is changed
virus is latin for
poison
Capsomeres are composed of________
protein, protein molecules, protein subunits, or proteins
Which of the following best describes a prion?
proteinaceous infectious agent
A_____ is the stage of an animal virus life cycle which is integrated into the host cell's genome.
provirus
When it comes to virus multiplication, viral exocytosis refers to ______.
release
HIV is described as a(n)______ because it synthesizes DNA from RNA using reverse transcription.
retrovirus
What are viruses called which are capable of converting their RNA genomes into DNA?
retroviruses
Most human viral infections are
self-limiting
Viral glycoproteins that protrude from the viral envelope and attach to host cell receptors are termed ___________
spikes, peplomers, or glycoprotein spikes
Viruses are classified into families based on genetic makeup, chemical composition, and ______.
structure
A _____occurs when a virus induces multiple cells to fuse making a large multinucleated cell.
syncytium or syncytia
Identify any of the following which can be used as primary cell lines.
Any of the answers listed here
Identify all the methods that a virus can use to gain entry into an animal cell.
-Fusion of the viral envelope and the cell membrane.-Engulfment/phagocytosis of the virus.
Which structure immediately encloses viral nucleic acid?
Capsid
The term______ is used to describe how some viruses burst cells during the release stage of viral multiplication.
Lysis
Which term correctly refers to viral bursting of any host cell?
Lysis
______ active viral infections lead to cell death.
Most
During the________ step in the viral multiplication cycle, capsids and genetic material are packaged into virions. Please give the specific term for this step.
Assembly
Which of the following describes the various viral parts coming together to produce virions?
Assembly
Identify the different environments in which some viruses can replicate.1. Bacterial cells2. Animal cells3. Saliva4. Marine water5. Freshwater6. Human cells
Bacterial cells Animal cells Human cells
What term is used to specifically describe the types of viruses that infect bacteria?
Bacteriophage
Identify prion related diseases. Multiple select question. Bovine spongiform encephalopathy Lyme disease Creutzfeldt-Jakob disease primary amebic meningoencephalitis
Bovine spongiform encephalopathy Creutzfeldt-Jakob disease
In which way do enveloped viruses leave their host cell?
Budding
Mature enveloped viruses are released from host cells via ________or exocytosis.
Budding
Which of the following viral release methods will not initially destroy the cell?
Budding
Which is closest in physical proximity to the nucleic acid of a virus?
Capsid
A(n) ____________ is a protein subunit that forms the viral capsid.
Capsomere
Which of the following is the monomeric unit for a viral capsid?
Capsomere
Identify the virus types which are released from host cells by lysis.
Complex Naked
Which prion-associated spongiform encephalopathy is marked by dementia, impaired senses, and uncontrolled muscle contractions?
Creutzfeldt-Jakob disease
Where are most RNA viruses replicated and assembled within the host?
Cytoplasm
Identify all the components of the nucleocapsid. Multiple select question. Polymerase Nucleic acid Scaffolding proteins Envelope Capsid
Nucleic acid Capsid
Where are most DNA viruses replicated and assembled within the host?
Nucleus
A cell harboring a virus that is not causing cytopathic effects is characteristic of which type of infection?
Persistent infection
Which macromolecule composes capsomeres?
Proteins
Which of the following describe an animal virus that has integrated its genome into the host cell's genome?
Provirus
A single virion could contain a genome of
RNA only DNA only
In animal viruses, newly made ________is used to synthesize viral proteins.
RNA or mRNA
Which factor enables certain laboratory animals to propagate viruses more readily than others?
Receptor specificity between virus and particular animal hosts
Which of the following viral structures typically make enveloped viruses very species-specific for the host cell they infect?
Receptors in the envelope
Which of the following structures of enveloped viruses must be specific for adsorption?
Spike proteins
What term is used to describe the viral proteins which protrude from the envelope and aid in attachment to host receptors?
Spikes
Which are the three main criteria used in classifying viruses into families?
Structure Genetic makeup Chemical composition
Which of the following is a multinucleated mass of cells due to the cytopathic effect of viral infection?
Syncytium
_______infections are those which cells are infected yet show no cytopathic effects.
persistent
A(n)____ is a proteinaceous infectious agent associated with spongiform encephalopathies.
prion
Phage DNA that is latently incorporated into the bacterial host genome is called a________
prophage
At minimum, viruses are composed of nucleic acid covered by a coating comprised of
protein
Which term is used to describe the phospholipid bilayer found surrounding the capsid of some viruses?
Envelope
Which types of viruses are released by budding?
Enveloped viruses
True or false: Bacteriophages infect eukaryotic and prokaryotic microorganisms.
False
True or false: Most bacteria engulf bacteriophages as part of the phage replication strategy.
False
Which of the following term describes the total nucleic content of a virus?
Genome
What are the viral spikes typically composed of?
Glycoproteins
The____________ range defines the limitations of the type of cell that a virus can invade.
Host
Which of the following is a term used to describe the different host cells which a virus can infect?
Host range
Different viruses can infect which of the following?
Human, bacterial, or plant cells
_______bodies are masses of viruses or damaged organelles of a cell due to a cytopathic effect of viral infection.
Inclusion
Which of the following is a mass of viruses or damaged organelles due to the cytopathic effect of viral infection?
Inclusion body
What term is used to define the process of a prophage being activated and entering into the lytic cycle?
Induction
Hepatitis viruses have a tropism for cells of the ______.
liver
When a bacterium acquires a new trait from a temperate phage, _____conversion has occurred
lysogenic
When a temperate phage infects a bacterium which gives the bacterium new traits, this is called ______
lysogenic conversion
Which term refers to the persistence of bacteriophages within host cells?
lysogeny
A ___________virus does not have an envelope surrounding its capsid.
naked
A nonenveloped virus is also called a(n) ______ virus.
naked
Capsids of ______ helical viruses are rigid and tight, while capsids of ______ helical viruses are flexible and loose.
naked; enveloped
The ___________ refers to the capsid and nucleic acid of a noneveloped virus.
nucleocapsid
The____ refers to the capsid and nucleic acid of a nonenveloped virus.
nucleocapsid
Viruses that are_____ lead to cancer in infected hosts.
oncogenic, oncovirus, or oncoviruses
In some viruses, including HIV, the enzyme______ ________ transcribes RNA into DNA.
reverse transcriptase
An enzyme capable of taking an RNA genome and generating a DNA copy is called ______.
reverse transcriptase
When an enveloped virus buds off the cell membrane, the membrane differs ______ from the host cell's membrane.
significantly
Identify all the types of nucleic acid genomes which have been discovered carried by various bacteriophages. Both ss and ds RNA in a single phage Both RNA and DNA in a single phage ssRNA ssDNA Both ss and ds DNA in a single phage dsDNA
ssRNA ssDNA dsDNA
At a minimum, a viral genome must include genes for
synthesizing the viral capsid packaging the mature virus particles regulating the actions of the host cell
A_______ phage is a bacteriophage that incorporates itself into the host genome as a lysogenic prophage.
temperate
A virus that only infects cells of a specific tissue in the body is described as having a ______.
tropism
True or false: Inoculation of laboratory animals is an in vivo method of viral cultivation.
true
The process of ________occurs when viruses lose their envelope during penetration into a host cell or when the envelope/capsid is are dissolved within a vacuole.
uncoating
Genes for synthesizing the viral capsid, for regulating actions of the host cell, and for packaging the mature virus are found in the ______ genome.
viral
At minimum, all viruses are composed of
Nucleic acids Proteins
which of the following best describe the relationship between viruses and their host cell?
Parasitism
Bacteriophages can infect which of the following? Eukaryotes only Both prokaryotes and eukaryotes Prokaryotes only
Prokaryotes only
Which of the following is used to describe the phage DNA that is latently incorporated into the bacterial host genome?
Prophage
True or false: Budding viruses do not lyse the host cell during release.
True
Which term describes the process of a virus losing its capsid and exposing viral nucleic acids to the immediate environment?
Uncoating
Viruses ______ depend on a host cell for replication.
completely
Most bacteriophages have________ -stranded DNA genomes.
double
Viruses which have a series of rod-shaped capsomer proteins linked together forming a series of interconnected hollow discs are termed ______.
helical
Two shapes of viral capsids are__________, which resembles a bracelet; or ____________, which is a type of polyhedron.
helical icosahedral or icosahedron
Through the process of ________, a prophage is activated and enters the lytic cycle.
induction
Lysogeny is best described as
integration of the viral genome into the host chromosome
Typically, naked helical viruses are ______ flexible than enveloped helical viruses.
less
True or false: Bacteriophages can contain double-stranded or single-stranded DNA or RNA.
true
True or false: Most active viral infections lead to cell death regardless of the type of release process.
true
True or false: Most infections caused by animal viruses do not result in death of the host organism.
true
True or false: Viruses are among the smallest infective agents.
true
True or false: Viruses can contain either DNA or RNA, but not both. True false question.
true
A fully formed virus that is able to establish an infection in a host cell is often called a ______.
virion
A virus that parasitizes another virus is called a(n) ______.
virophage
Louis Pasteur proposed the term ______, Latin for "poison", to denote a special group of infectious agents.
virus
The term "in _______" implies that a virus is being propagated in a living animal.
vivo
_________is the viral process of attaching to the host cell receptor for the virus.
Adsorption
List the correct order of viral life cycle phases, starting with the first at the top.
1. Adsorption2. Penetration3. Uncoating4. Synthesis5. Assembly6. Release
Which two of the following statements about virophages are correct? Multiple select question. Virophages are specific for the AIDS virus, and are being developed as a vaccine. Virophages are being developed to treat cancers caused by oncogenic viruses. A virophage is a virus that parasitizes another virus. A virophage uses genes from another virus for its own replication.
A virophage is a virus that parasitizes another virus. A virophage uses genes from another virus for its own replication.
Which is the correct term to describe viral adherence to a host cell receptor?
Adsorption
Which viral stage occurs first?
Adsorption
What name is given to a phage "type" which can incorporate itself into the host genome as a lysogenic prophage?
Temperate
Which is NOT a reason that eggs provide an excellent in vivo viral cultivation system?
The egg contains a tissue monolayer
Which term describes the integration of an oncogenic virus that changes mammalian host DNA?
Transformation
True or false: Both naked and complex viruses are released from host cells via lysis once mature.
True
Identify any of the following pathways which could produce proteins used by viruses.
Viral positive-ssRNA --> proteins used by viruses Host DNA --> mRNA --> proteins used by viruses
Which two of the following mechanisms are found to result in cancer caused by a virus? Multiple select question. Bacteriophages from host microbiota infect host cells to cause cancer. Viral proteins cause changes in growth regulation, leading to cancer. The virus carries genes that can cause the cancer. Viruses carry genes from an existing tumor to other body sites to cause cancer.
Viral proteins cause changes in growth regulation, leading to cancer. The virus carries genes that can cause the cancer.
Which is most important for attachment of a virus to a host cell?
Viral specificity for host receptors
Identify the smallest pathogenic agent.
Virion
Which of the following statements regarding the membrane on an enveloped virus is true?
Viruses insert their own proteins in the membrane.
Any virus that specifically infects bacteria is called a(n) .________
bacteriophage
two ways in which newly assembled viruses are released from host cells are through ___________ or exocytosis by enveloped viruses, and through _________ by naked viruses
budding lysis or cell lysis
Some retroviruses carry oncogenes that may incorporate into the host cell DNA and ultimately result in ______.
cancer
The structure directly surrounding the viral nucleic acid is the___________a coat of proteins.
capsid
Most bacteriophages contain which type of nucleic acid?
dsDNA
Viral nucleic acids are ______.
either single-stranded or double stranded
The 2 principle processes by which viruses penetrate host cells are |_______________(engulfment) and direct fusion.
endocytosis
True or false: The viral envelope and capsid are the same thing. True false question.
false
True or false: Viruses which can lead to cancer are termed carcinoviruses.
false
The total nucleic acid content of a virus can be referred to as the viral .___________
genome
