MicroBio Chapter 5
True or false: Antibiotics are an effective treatment for most viral infections.
False
True or false: The interior of eggs normally contains non-pathogenic bacterial cells but no viruses.
False
True or false: The viral envelope and capsid are the same thing.
False
Which of the host cell structures must usually be specific for adsorption?
Glycoprotein receptors
Which of the following is a term used to describe the different host cells which a virus can infect?
Host range
What are the three main criteria used to classify viruses?
Structure Genetic makeup Chemical composition
When a cell harbors a virus that is not immediately lysing the cell, it's known as what type of infection?
Persistent infection
Which factor enables certain laboratory animals to propagate viruses more readily than others?
Receptor specificity between virus and particular animal hosts
In which stage of viral multiplication would you expect to see "budding" occur?
Release
In viral multiplication, capsids and genetic material are packaged into virus particles during the _________step.
assembly
Mature virus particles are constructed from nucleic acid and protein during the ______ phase of the viral life cycle.
assembly
The step in viral multiplication in which capsids and genetic material are packaged into virions.
assembly (viral)
Antibiotics are effective at combating ______ but not ______.
bacteria; viruses
A virus that infects bacterial cells is called a(n) ______.
bacteriophage
A virus that specifically infects bacteria.
bacteriophage
During the release stage of the viral multiplication cycle, enveloped viruses leave their host cells through ________ , or exocytosis.
budding
During the release stage of the viral multiplication cycle, enveloped viruses leave their host cells through_________ , or exocytosis.
budding
Two ways in which newly assembled viruses are released from host cells are through _______ or exocytosis by enveloped viruses, and through ___________ (rupture) by naked viruses.
budding lysis, cell lysis, lyses, or lysing
Two ways in which newly assembled viruses are released from host cells are through________ or exocytosis by enveloped viruses, and through ___________(rupture) by naked viruses.
budding lysis, cell lysis, lyses, or lysing
Enveloped viruses are released from host cells through ______ or exocytosis, while naked viruses are released through ______ (rupture).
budding; lysis
The protein covering of a virus's nucleic acid core. Capsids exhibit symmetry due to the regular arrangement of subunits called capsomers. See icosahedron.
capsid
At minimum, viruses are composed of nucleic acid and a ___________ comprised of protein.
capsid or shell
A subunit of the virus capsid shaped as a triangle or disc.
capsomere
Identical protein subunits that make up the viral capsid are called ______.
capsomeres
The degenerative changes in cells associated with virus infection. Examples: the formation of multinucleate giant cells (Negri bodies), the prominent cytoplasmic inclusions of nerve cells infected by rabies virus.
cytopathic effect
In penetration by ______, the entire virus is engulfed by the cell and enclosed in a vacuole or vesicle.
endocytosis
The process whereby solid and liquid materials are taken into the cell through membrane invagination and engulfment into a vesicle.
endocytosis
The type of penetration that occurs when viruses are taken into the cell followed by engulfment in a vacuole or vesicle is called ________
endocytosis or phagocytosis
A virus whose nucleocapsid is enclosed by a membrane derived in part from the host cell. It usually contains exposed glycoprotein spikes specific for the virus.
enveloped virus
The complete set of chromosomes and genes in an organism.
genome
The sum total of the genetic information carried by a virus is called the viral ____________
genome
The total nucleic acid content of a virus can be referred to as the viral _______
genome
The total nucleic acid content of a virus can be referred to as the viral ___________
genome
Protein covering of viruses made of rod-shaped capsomeres that form a coiled nucleic acid/capsid structure.
helical capsid
The limitation of the type of cell that a virus can invade is called the _______ range.
host
The limitation imposed by the characteristics of the host cell on the type of virus that can successfully invade it.
host range
A regular geometric figure having 20 surfaces that meet to form 12 corners. Some virions have capsids that resemble icosahedral crystals.
icosahedron
Methods to study viruses that use living animals are called _____ methods, whereas methods that use tissue culture are called _____ methods.
in vivo; in vitro
One type of cytopathic effect is the accumulation of ______, compacted masses of viruses or damaged cell organelles within an infected host cell.
inclusion bodies
Which of the following is a mass of viruses or damaged organelles caused by viral infection of a cell?
inclusion body
The process whereby a bacteriophage in the prophage state is activated, begins replication, and enters the lytic cycle.
induction
Which of the following are in vivo methods for viral cultivation?
inoculating mice with viruses inoculating chicken eggs with viruses
Viruses have tropisms, that is they can infect ______.
only cells of a certain tissue type
The step in viral multiplication in which virus enters the host cell.
penetration (viral)
Infections in which cells harbor the virus but are not immediately lysed are called ________ infections.
persistent or latent
In viruses, the close physical combination of the nucleic acid with its protective covering.
nucleocapsid
Some animal viruses are called ______ because they enter a host cell and permanently alter its genetic material, leading to cancer.
oncogenic
Mammalian virus capable of causing malignant tumors.
oncovirus
A clear area where virus-infected monolayers of cells have been disrupted or destroyed is called a(n)
plaque
In virus propagation methods, the clear zone of lysed cells in tissue culture or chick embryo membrane that corresponds to the area containing viruses. In dental application, the filamentous mass of microbes that adheres tenaciously to the tooth and predisposes to caries, calculus, or inflammation.
plaque
When observing a monolayer of cells, the areas where virus-infected cells have been destroyed show up as clear, well-defined patches called ______.
plaques
A concocted word to denote "proteinaceous infectious agent"; a cytopathic protein associated with the slow-virus spongiform encephalopathies of humans and animals.
prion
An infectious agent made up of only protein and associated with spongiform encephalopathies is a(n)
prion
Some diseases of the nervous system result from an infectious agent in the form of protein fibrils that is called a ______.
prion
A lysogenized bacteriophage; a phage that is latently incorporated into the host chromosome instead of undergoing viral replication and lysis.
prophage
A bacteriophage that incorporates itself into the host genome as a lysogenic prophage is called a(n) _______phage.
temperate
A bacteriophage that enters into a less virulent state by becoming incorporated into the host genome as a prophage instead of in the vegetative or lytic form that eventually destroys the cell.
temperate phage
The category of DNA phages that can participate in a lytic phase or enter into a lysogenic cycle is the ______.
temperate phages
In microbial genetics, the transfer of genetic material contained in "naked" DNA fragments from a donor cell to a competent recipient cell.
transformation
Viruses that can infect only certain tissues are described as having a tissue specificity or _____.
tropism
The process of removal of the viral coat and release of the viral genome by its newly invaded host cell.
uncoating
The process that occurs when viruses lose their capsid (and envelope, if they have one) during or after penetration into a host cell is called _________
uncoating
An elementary virus particle in its complete morphological and thus infectious form. A virion consists of the nucleic acid core surrounded by a capsid, which can be enclosed in an envelope.
virion
An infectious agent that, unlike a virion, lacks a capsid and consists of a closed circular RNA molecule. Although known viroids are all plant pathogens, it is conceivable that animal versions exist.
viroid
The part of the human microbiome that includes all of the viruses that are associated with the body is called the human
virome
The human virome is the complete set of ______.
viruses that are associated with the human body
A multinucleated protoplasmic mass formed by consolidation of individual cells.
syncytium
The step in viral multiplication in which viral genetic material and proteins are made through replication and transcription/translation.
synthesis (viral)
Unlike cellular organisms, viruses are unable to ______
synthesize their own proteins
Unlike cellular organisms, viruses are unable to ______.
synthesize their own proteins
Which is the correct term to describe viral adherence to a host cell receptor?
Adsorption
Which viral stage occurs first?
Adsorption
Which of the following describes the various viral "parts" coming together to produce virus particles?
Assembly
What term is used to specifically describe the types of viruses that infect bacteria?
Bacteriophage
Which is closest in physical proximity to the nucleic acid of a virus?
Capsid
Which of the following is the monomeric unit of a viral capsid?
Capsomere
What term refers to a virus that can lead to cancer?
Oncogenic virus
True or false: Most viral infections do not result in death of the host organism.
True
Which term describes the process of a virus losing its capsid (and envelope, if it has one) and exposing viral nucleic acids to the immediate environment?
Uncoating
Which is most important for attachment of a virus to a host cell?
Viral specificity for host receptors
Identify the smallest pathogenic agent.
Virus
________ are among the smallest infective agents.
Viruses
Which of the following is true regarding viruses?
Viruses are not cellular.
A process of adhering one molecule onto the surface of another molecule.
adsorption
A virus binds to specific receptor sites on the membrane of a susceptible host cell during the ______ phase of the viral life cycle.
adsorption
The virus shown here binding to host cell proteins is in the _____ stage of the viral life cycle. Multiple choice question. release
adsorption
List the correct order of viral life cycle phases, starting with the first at the top. Position 1 of 5 Adsorption correct toggle button unavailable Adsorption
adsorption, penetration and uncoating, synthesis, assembly, and release
Embryonic eggs ______.
are completely sterile
Unlike organisms such as bacteria and protozoa, viruses ______.
are not cellular
To burst.
lyse
A bacterium acquires a new genetic trait due to the presence of genetic material from an infecting phage.
lysogenic conversion
The indefinite persistence of bacteriophage DNA in a host without bringing about the production of virions.
lysogeny
This virus is in the adsorption stage of its life cycle, where it attaches to _____ from the host cell.
membrane receptors
Although the outer shell of viruses is made of ______, viruses lack the machinery to produce those shell components on their own.
protein
All viruses have two parts: a ______ covering and ______ located in a central core.
protein; DNA or RNA
Most host cell receptors that viruses attach to are actually _______ that the cell uses in normal function.
proteins
Viruses typically attach to what type of host membrane receptors?
proteins
The genome of a virus when it is integrated into a host cell's DNA.
provirus
The final step in the multiplication cycle of viruses in which the assembled virus particle exits the host cell and moves on to infect another cell.
release
An enzyme capable of taking an RNA genome and generating a DNA copy is called ______.
reverse transcriptase
An enzyme that can synthesize DNA from RNA is called ______.
reverse transcriptase
Most human viral infections are ______.
self-limiting
Some laboratory animals can propagate viruses in the laboratory more readily than others because many viruses exhibit host ________
specificity
Some laboratory animals can propagate viruses in the laboratory more readily than others because many viruses exhibit host __________
specificity
Viruses are classified based on genetic makeup, chemical composition, and ______.
structure
