MCB CH 6
Which is the correct term to describe viral adherence to a host cell receptor?
Adsorption
Which of the following is a common feature of continuous cell lines? No mutations, normal morphology Continuous growth Meiotic division
Continuous growth
Which term describes a nonliving microscopic agent?
Infectious particle
When phage nucleic acid is incorporated into the nucleic acid of its host cell and is replicated when the host DNA is replicated, this is considered part of which cycle? Cell cycle Multiplication cycle Virulence cycle Lysogenic cycle Lytic cycle
Lysogenic cycle
Which term refers to the persistence of bacteriophages within host cells?
Lysogeny
Which term refers to the persistence of bacteriophages within host cells? latency lysogeny
Lysogeny Lysogeny refers to temperate bacteriophages while latency refers to the persistence of animal viruses.
Identify the commonalities between temperate phages and lytic phages. Integration of the viral genome into the host genome Release Biosynthesis of viral components Penetration Adsorption Assembly
Release Biosynthesis of viral components Penetration Adsorption Assembly
Which type of phage generally can increase the pathogenicity of a bacterium?
Temperate phage
Select the three choices which are the primary purposes of cultivating viruses.
To isolate viruses from clinical specimens To prepare viruses for vaccines To research the biology of viruses
Which term describes the process of a virus losing its capsid and exposing viral nucleic acids to the immediate environment?
Uncoating
Which type of capsids are composed of multiple protein types and nonsymmetrical shapes?
complex
The two principal processes by which viruses penetrate host cells are _________ (engulfment) and direct fusion.
endocytosis
True or false: Primary cell cultures are naturally long-lived or immortal.
false- Primary cell lines can mutate into continuous cell lines that exhibit immortality.
The membrane receptors that viruses attach to during adsorption are typically composed of ______.
glycoproteins
What are the viral spikes typically composed of?
glycoproteins
Viruses with a _____ capsid have rod-shaped capsomers, while the capsomers of viruses with _______ capsids are arranged as a multifaceted polygon
helical icosahedral
Viral transformation implies ______.
host DNA is changed
Viruses which have symmetrical polygonal capsids are called ______.
icosahedral
Which Latin phrase describes the cultivation or testing "in glass" or outside of a living organism?
in vitro In vivo means "in life" or in the living organism.
The ____________ refers to the capsid and nucleic acid of a nonenveloped virus.
nucleocapsid
Phage DNA that is latently incorporated into the bacterial host genome is called a
prophage
True or false: The interior of eggs normally contains non-pathogenic bacterial flora but no viruses.
False The interior of eggs is normally a sterile environment and free from any type of microbes or viruses.
______ viruses in the human body are pathogenic. Most All Few None
Few
Different viruses can infect which of the following? Human cells only Bacterial cells only Human, bacterial, or plant cells Plant cells only
Human, bacterial, or plant cells
Which Latin phrase describes the cultivation or testing within a living organism?
In vivo In vitro means "in glass" or in a test tube.
What term is used to define the process of a prophage being activated and entering into the lytic cycle?
Induction
What was the significance of the discovery of filterable viruses? It demonstrated that infections could only be caused by cellular, rather than acellular, microbial agents. It demonstrated that infections could be caused by agents that were smaller than bacteria. It demonstrated that viruses could infect bacteria.
It demonstrated that infections could be caused by agents that were smaller than bacteria.
Which of the following would you expect to see from bacteriophage propagation? Lesion Clumping of cells Multinucleated cells Plaques
Plaques
Which of the following is used to describe the phage DNA that is latently incorporated into the bacterial host genome?
Prophage
Which of the following best describes a prion? Proteinaceous infectious agent RNA-based infectious agent Obligate aerobe Obligate intracellular parasite
Proteinaceous infectious agent
What are viruses called which are capable of converting their RNA genomes into DNA?
Retroviruses
Which of the following is an enzyme found in HIV that is responsible for converting its RNA genome into a DNA genome? Reverse polymerase Auto convertase Reverse transcriptase Retro transcriptase
Reverse transcriptase
What term is used to describe a virus type which depends on other viruses for replication? Eclipse virus Satellite virus Temperate virus Rho-dependent virus
Satellite virus
Which two of the following statements regarding the human virome are true? Some viruses are in a dormant state in the body. Most viruses in the human virome are pathogenic. The human virome includes viruses that infect our commensal bacteria. Only a few cell types in the human body are susceptible to viru
Some viruses are in a dormant state in the body. The human virome includes viruses that infect our commensal bacteria.
Transduction leads to which important consequence? Multiple choice question. Increased side effects to antiviral drugs in the patient Spread of drug resistance in bacteria Decreased immunity in the host
Spread of drug resistance in bacteria
True or false: Viruses cannot be called organisms.
True: The word organism infers the qualities of "life" and viruses are not living.
Select the three methods that are used to cultivate viruses.
Use of cell culture techniques Use of animal inoculation Inoculation of embryonated eggs
What does "obligate" mean in regard to viruses? Viruses are infectious Viruses are airborne Viruses must have a host cell Viruses are composed of proteins and nucle
Viruses must have a host cell
List the correct order of viral life cycle phases, starting with the first at the top. synthesis release assembly adsoption penetration/uncoating
adsoption penetration/uncoating synthesis assembly release
_______ is the viral process of attaching to the host cell receptor for the virus.
adsorption
It is well known that have _________ no effect on treating viral infections.
antibiotics
Embryonic eggs ______. are completely sterile have a few non-pathogenic bacteria
are completely sterile
Which of the following describes the various viral parts coming together to produce virions? Assembly Absorption Release Penetration
assembly
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/maturation
Mature enveloped viruses are released from host cells via ________ or exocytosis.
budding
The word __________ is used to describe viruses which have a non-icosahedral or non-helical arrangement of capsomer proteins.
complex
Where are most RNA viruses replicated and assembled within the host?
cytoplasm
Most bacteriophages have _______ -stranded DNA genomes.
double
Most bacteriophages contain which type of nucleic acid?
dsDNA
This micrograph illustrating viruses documents that the best method for viewing viruses is
electron microscope
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? RNA viruses Enveloped viruses DNA viruses Naked viruses
enveloped
Which two of the following are cytopathic effects in virally infected animal cells? Prions Inclusions Viroids Syncytia
inclusions syncytia
Through the process of __________ , a prophage is activated and enters the lytic cycle.
induction
Which of the following terms is used to describe a viral RNA genome which CANNOT be immediately translated into protein? Neutral Negative-sense Transcription Positive-sense
negative sense
Where are most DNA viruses replicated and assembled within the host? rough er cytoplasm dna
nucleus dna replicated in nucleus for host cells
Which three of the following steps are found in both the animal virus life cycle and the bacteriophage life cycle? Multiple select question. penetration uncoating adsorption assembly oncogenesis
penetration adsorption assembly
A(n) ________ is a proteinaceous infectious agent associated with spongiform encephalopathies.
prion
Viral glycoproteins that protrude from the viral envelope and attach to host cell receptors are termed
spikes
True or false: Bacteriophages can increase the pathogenicity of their bacterial host.
true
True or false: Both naked and complex viruses are released from host cells via lysis once mature.
true
True or false: Viral nucleic acid may be single-stranded or double-stranded DNA or RNA.
true
True or false: Interferons are naturally produced during some viral infections.
true- Interferons are produced by cells in response to many types of viral infections.
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
Which of the following steps of the animal virus life cycle is not found in the bacteriophage life cycle? assembly lysis penetration uncoating adsorption
uncoating
A fully formed virus that is able to establish an infection in a host cell is often called a ______.
virion
A single virus particle is known as a(n)
virion
Identify the different environments in which some viruses can replicate. Bacterial cells Animal cells Human cells Marine water Freshwater
Bacterial cells Animal cells Human cells
______ phages enter the prophage state, while ________ phages burst the host cell.
Blank 1: Temperate or Lysogenic Blank 2: lytic, virulent, or T-even
Identify all the components of the nucleocapsid. Scaffolding proteins Polymerase Envelope Capsid Nucleic acid
Capsid Nucleic acid
Which two of the following are cytopathic effects in virally infected animal cells? Change in cell shape Appearance of plaques Change in cell size Production of viroids
Change in cell shape Change in cell size Reason: Plaques are associated with virally infected bacterial cells.
Identify the virus types which are released from host cells by lysis.
Complex Naked
A single virion could contain a genome of
DNA only RNA only
Identify all the methods that a virus can use to gain entry into an animal cell. Engulfment/phagocytosis of the virus Injection of viral nucleic acids across the cell membrane Fusion of the viral envelope and the cell membrane
Engulfment/phagocytosis of the virus Fusion of the viral envelope and the cell membrane Not Injection of viral nucleic acids across the cell membrane Reason: This is the method used by bacteriophages but bacteriophages cannot infect animal cells.
True or false: "Transduction" has been linked to the spread of antibiotic resistance in bacteria.
t- Reason: Transduction is the process during which a phage is released from a bacterial cell but it carries a portion of the host cell's genome rather than viral genes and infects a new cell. The phage could bring with it antibiotic resistant genes to the new bacterial cell.
A ______ phage is a bacteriophage that incorporates itself into the host genome as a lysogenic prophage.
temperate
A bacteriophage that incorporates itself into the host genome as a lysogenic prophage is called a(n) ______phage.
temperate
Which term describes the integration of an oncogenic virus that changes mammalian host DNA?
transformation
Lysogeny is best described as ______. lysis of the host cell replication of virions fragmentation of the host chromosome integration of the viral genome into the host chromosome
integration of the viral genome into the host chromosome
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 ______. latency lysogenic cycle lysogenic conversion
lysogenic conversion
In a chronic latent state, a virus will ______. rely on host ribosomes to make its proteins remain dormant in cells for years lose its glycoprotein spikes adsorb to many different cell types
remain dormant in cells for years
HIV is described as a(n) ________ because it synthesizes DNA from RNA using reverse transcription.
retrovirus
An enzyme capable of taking an RNA genome and generating a DNA copy is called ______. retro transcriptase reversable genetics reverse translation reverse transcriptase
reverse transcriptase
The enzyme _______ ________ is a preformed protein carried in by HIV responsible for converting its RNA genome into DNA.
reverse transcriptase