Chapter 6 microbiology
In which way do enveloped viruses leave their host cell?
Budding
which protein-associated spongiform encephalopathy is marked by dementia, impaired senses, and uncontrolled muscle contractions.
Creutzfeldt-Jakob disease
A single virion could contain a genome of
DNA only or RNA only but not both
viral nucleic acids are
Either single-stranded or double stranded
identify any of the following pathways which could produce proteins used by viruses.
Host DNA --> mRNA--> proteins used by viruses Viral positive-ssRNA--> proteins used by viruses
In animal viruses, newly made ___ is used to synthesize viral proteins
RNA
which of the following is the monomeric unit for a viral capsid?
capsomere
viruses ____ depend on a host cell for replication
completely
identify the virus types which are released from host cells by lysis
complex and naked
identify prion related diseases
creutzfeldt-Jakob disease and Bovine spongiform encephalopathy
where are most RNA viruses replicated and assembled within the host
cytoplasm
Most bacteriophages have ____-stranded DNA genomes
double
most bacteriophages have _____-stranded DNA genomes
double
Most bacteriophages contain which type of nucleic acid?
dsDNA
identify all the types of nucleic acid genomes which have been discovered carried by various bacteriophages.
dsDNA ssDNA ssRNA
The 2 principle processes by which viruses penetrate host cells are _____ (engulfment) and direct fusion
endocytosis
The process of _______, a type of penetration, occurs when viruses are taken into the cell followed by engulfment in a vacuole or vesicle
endocytosis
bacteria are incapable of...
engulfment and phagocytosis
identify all the methods that a virus can use to gain entry into an animal cell
engulfment/phagocytosis of the virus, and fusion of the viral envelope and the cell membrane
which term is used to describe the phospholipid bilayer found surrounding the capsid of some viruses ?
envelope
A_____ virus has a membranous layer external to the nucleocapsid.
enveloped virus
Typically, naked helical viruses are ____ flexible than enveloped helical viruses.
less
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
when bacterium Acquires a new trait from a temperate phage, _______ conversation has occurred
lysogenic
when a temperate phage infects a bacterium which give the bacterium new traits, this is called....
lysogenic conversation
which term refers to the persistence of bacteriophages within host cells
lysogeny
_______ active viral infections lead to cell death
most
A ____ virus does not have an envelope surrounding its capsid
naked
what is the order of viral cycle phases, starting with the first
Adsorption Penetration Uncoating Synthesis Assembly and Release Andy, Please Use SARah
identify the different environments in which some viruses can replicate
Human cells, Bacterial cells, and Animal cells
different viruses can infect which of the following ?
Human, bacterial, or plants cells e.g: bacteria algae fungi protozoa plants and animals
which of the following is used to describe the phage DNA that is latently incorporated into the bacterial host genome
PROPHAGE
in animal viruses, newly made ______ is used to synthesize viral proteins
RNA
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
In some viruses, including HIV, the enzyme _______ _________ transcribes RNA into DNA
Reverse transcriptase
when an enveloped virus buds off the cell membrane, the membrane differs _____ from the host cell's membrane
Significantly
which of the following is a multinucleated mass of cells due to the CPE of viral infection?
Syncytium
bacteriophages can contain double-stranded DNA or RNA
TRUE
which term describes the integration of an oncogenic virus that changes mammalian host DNA
Transformation
At minimum, all viruses are composed of
a covering aka a capsid (envelope) and a central core containing nucleic acid (DNA or RNA) (Matrix proteins) (one or two enzymes)
oncogenic
a naturally occurring type of gene that when activated can transform a normal cell into a cancer cell
syncytia- respiratory syncytial virus
a result of some viruses ability to fuse membranes
which two of the following statements about virophages are correct?
a virophage uses genes from another virus for its own replication. A virophage is a virus that parasitizes another virus
______ is the viral process of attaching to the host cell receptor for the virus
adsorption
which is the correct term to describe viral adherence to a host cell receptor?
adsorption
during the _____ step in the viral multiplication cycle, capsids and genetic material are packaged into virions
assembly
which of the following describes the various parts coming together to produce virions ?
assembly
any virus that specifically infects bacteria is called a
bacteriophage
what term is used to specifically describe the types of viruses that infect bacteria ?
bacteriophage
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-slowly sheds off
Two ways in which newly assembled viruses are released from host cells are through _______ (exocytosis) by enveloped viruses, and through ________(rupture) by naked viruses.
budding; lyses
persistent infections
can last from a few weeks to the remainder of the hosts life... some cells will develop a carrier relationship, in which the cell harbors the virus and is not immediately lysed.
some retroviruses carry oncogenes that may incorporate into the host cell DNA and ultimately result in _____
cancer
identify any of the following which can be used as primary cell lines
cancer cells Embryonic tissue adult tissue cells fetal cells
most cell lines used to propagate virus are
cancerous cells
the structure directly surrounding the viral nucleic acid is the ____ a coat of proteins
capsid
which is closest in physical proximity to the nucleic acid of a virus
capsid
which is closest in physical proximity to the nucleic acid of a virus?
capsid
which structure immediately encloses viral nucleic acid ?
capsid
identify all the components of a nucleocapsid
capsid and nucleic acid
A ___ is a protein subunit that forms the viral capsid
capsomere
which type of virus are released by budding?
enveloped viruses
Budding is a type of ______ process where enveloped viruses are released from the host cell membrane
exocytic
bacteriophages infect eukaryotic and prokaryotic microorganism's
false
chicken eggs have a monolayer of cells within them which offer a good place to propagate virus.
false
which are the main three criteria used in classifying viruses into families ?
genetic makeup, chemical composition and structure
The total nucleic acid content of a virus can be referred to as the viral ____
genome
which of the following term describes the total nucleic content of a virus
genome
The membrane receptors that viruses attach to during adsorption are typically composed of ...
glycoproteins
what are the viral spikes typically composed of?
glycoproteins
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 (rod shaped); and icosahedral
The ______ range defines the limitations of the type of cell that a virus can invade
host
Viral transformation implies ______
host DNA is changed
viral transformation implies
host DNA is changed
which of the following is a term used to describe the different host cells which a virus can infect?
host range
________ 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 bodies
through the process of _________, a prophage is activated and enters the lytic cycle
induction
what term is used to define the process of a prophage being activated and entering into the lytic cycle
induction
how do bacteriophage nucleic acid enter the host cell?
injection
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
hepatitis viruses have a tropism for cells of the _________
liver
The term ____ is used to describe how some viruses burst cells during the release stage of viral multiplication
lysis
A nonenveloped virus is also called a ____ virus
naked
identify the virus types which are released from host cells by lysis
naked and complex
The virus indicated by the letter A is a _____ virus
naked virus- the simplest virus is a naked virus (nucleocapsid) consisting of a geometric capsid assembled around a nucleic acid strand or strands.
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 nonenveloped virus
nucleocapsid
where are most DNA viruses replicated and assembled within the host?
nucleus
enveloped virus is composed...
of nucleocapsid surrounded by a flexible membrane called an envelope
which of the following best describe the relationship between viruses and their host cell?
parasitism
______ infections are those which cells are infected yet show no cytopathic effects
persistent
a cell harboring a virus that is not causing cytopathic effects is characteristic of which type of infection?
persistent infection
"Virus" is latin for ____
poison
A ____ is a proteinaceous infectious agent associated with spongiform encephalopathies
prion
bacteriophages can infect which of the following
prokaryotes only
Phage DNA that is latently incorporated into the bacterial host genome is called a _____
prophage
Capsomeres are composed of ____ (a macromolecule)
protein
At minimum, viruses are composed of nucleic acid covered by a coating comprised of
protein or capsomers
which of the following best describes a prion?
proteinaceous infectious agent- a cytopathic protein associated with the slow-virus spongiform encephalopathies of humans and animals
which macromolecule composes capsomeres
proteins
A _____ is the stage of an animal virus life cycle which is integrated into the host cell's genome
provirus
A ______ is the stage of an animal virus life cycle which is integrated into the host cells genome
provirus
which of the following describe an animal virus that has integrated its genome into the host cells genome
provirus
At minimum, a viral genome must include genes for
regulating the actions of the host cell, synthesizing the viral capsid, and packaging the mature virus particles
when it comes to virus multiplication, viral exocytosis refers to .....
release
HIV is described as a _______ 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
an enzyme capable of taking an RNA genome and generating a DNA copy is called _______
reverse transcriptase
Bacteriophages can contain dsDNA/dsRNA or ssDNA/ssRNA
true
Budding viruses do not lyse the host cell during release
true
Cancerous tissue can serve as a primary cell line for viral culture
true
Embryonic tissue can serve as a primary cell line for viral culture
true
Inoculation of laboratory animals in an in vivo method of viral cultivation
true
Viruses can contain DNA or RNA, but not both.
true
both naked and complex viruses are released from host cells via lysis once mature
true
budding viruses do not lyse the host cell during the release
true
most active viral infections lead to call death regardless of the type of release process
true
most infections caused by animal viruses do not result in death of the host organism
true
viruses are among the smallest infective agents.
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
which term describes the process of a virus losing its capsid and exposing viral nucleic acids to the immediate environment?
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
which two of the following mechanisms are found to result in cancer caused by a virus
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
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 ____
virion
Identify the smallest pathogenic agent
virion
A virus that parasitizes another virus is called a
virophage
Louis Pasteur proposed the term ______, Latin for "poison", to denote a special group of infectious agents
virus
enveloped virus
virus that contains additional layers around the nucleocapsid
cytopathic effects (CPEs)
virus-induced damage to the cell that alters its microscopic appearance
which of the following statements regarding the membrane on an enveloped virus is true?
viruses insert their own proteins in the membrane of the host cell
naked viruses
viruses that consist of only a nucleocapsid
the term "in ____" implies that a virus is being propagated in a living animal
vivo
provirus
when Viral DNA is incorporated into the DNA of the host
what viral stage occurs first?
adsorption
Most human viral infections are
self-limiting
which of the following structures of enveloped viruses must be specific for adsorption?
spike proteins
Viral glycoproteins that protrude from the viral envelope and attach to host cell receptors are termed...
spikes
what term is used to describe the viral proteins which protrude from the envelope and aid in attachment to host receptors?
spikes
A _____ occurs when a virus induces multiple cells to fuse making a large multinucleated cell
syncytia
A ____ occurs when a virus induces multiple cells to fuse making a large multinucleated cell
syncytium
A _____ phage is a bacteriophage that incorporates itself into the host genome as a lysogenic prophage
temperate
what name is given to a phage "type" which can incorporate itself into the host genome as a lysogenic prophage ?
temperate
one common CPE
the fusion of multiple host cells into single large cells containing multiple nuclei
which is A reason that eggs provide an excellent in vivo cultivation system ?
the interior environment of the egg is sterile AND the egg is self-supporting
A virus that only infects cells of a specific tissue in the body is described as having a
tropism