Ch. 5 Viruses Learn smart
Lysogeny is best described as:
integration of the viral genome into the host chromosome
When bacteriophages infect pathogenic bacteria resulting in new pathogenic trait its called _____
lysogenic conversion
Azidothymidine is an antiviral drug used to treat which viral stage
synthesis
Which of the following are cytopathic effect in virally infected animal cells?
-Syncytia -inclusion bodies
List the 3 purposes of viral cultivation
-To prepare vaccines - to identify viruses in clinical specimens -to study effects on host cells
Identify any of the following pathways which produce proteins used by viruses
-Viral positive- ssRNA-Proteins used by viruses -Host DNA-mRNA- proteins used by viruses
The suffix ____ is used to designate a viral family, while the suffix _____ is used to designate a viral genus.
-Viridae/ Virus
What facts best support the position that viruses are not living organisms?
-Viruses dont have any means of independent metabolism -viruses cannot reproduce on their own
List the correct order of viral life cycle phases
-adsorption -penetration/uncoating -synthesis -assembly -maturation -release
What can viruses NOT do
-consume food -replicate outside of a cell
Identify the commonalities between temperate phages and lytic phages
-penetration -biosynthesis of viral components -adsorption release -assembly
What cellular organisms can viruses infect?
-protozoa -bacteria -animals -plants fungi
Identify all the types of nucleic acid genomes which have been discovered carried by various bacteriophages
-ssRNA -ssDNA -dsDNA -dsRNA
_______ is the viral process of attaching to the host cell receptor for the virus.
Adsorption
Viruses were discovered by:
using a filter
It is well known that ______ have no effect on treating viral infections
Antibiotics
Unlike organisms such as bacteria and protozoa, viruses:
Are not cellular
Which of the following describes the various viral "parts" coming together to produce virus particles
Assembly
A type of virus that specifically infects bacteria is called a(n) ______
Bacteriophage
How many cases of viral infection occur worldwide annually?
Billions
Exocytosis, or _____, or enveloped viruses occurs from the host cell membrane during the release stage of the viral multiplication cycle
Budding
In which way do enveloped viruses leave their host cells?
Budding
Mature enveloped viruses are released from host cells via ____ or exocytosis
Budding
The acronym ____ is used for cytopathic effect.
CPE
At minimum, viruses are composed of nucleic acid and a _______ comprised of proteins
Capsid
Which structure immediately encloses viral nucleic acid?
Capsid
The arrow is pointing to a bacteriophage component called ___
Capsid head
What do Viroids Not have:
Capsid, mitochondrion, envelope, metabolic pathways
A(n) ________ is a protein subunit that forms the viral capsid
Capsomer
The monomer of a capsid is called a _____
Capsomer
Viruses _______ depend on a host cell for replication
Completely
Which is the typical route of infection for mad cow disease?
Consumption of contaminated food
Most RNA viruses will assemble the virion within the host cell's ____
Cytoplasm
Reverse transcriptase is a preformed viral enzyme that synthesizes the nucleic acid ____ from the nucleic acid ____
DNA;RNA
Viral DNA polymerase genes are expressed during the ____ stage of the synthesis phase of the viral life cycle
Early
Chicken ______ have a monlayer of cells within them which offer a good place to propagate virus.
Eggs
The 2 principle processes by which viruses penetrate host cells are engulfment or ____ and direct fusion.
Endocytosis
Naked viruses do not possess a(n) ________
Envelope
Which term is used to describe the phospholipid bilayer found surrounding the capsid of some viruses?
Envelope
True or false: the viral envelope and capsid are the same thing
False
The total nucleic acid content of a virus can be referred to as the viral _____
Genome
Most host cell receptors that viruses attach to are actually ______ that the cell uses in normal function
Glycoprotein
Viruses with a ______ capsid have a rod-shaped capsomers, while the capsomers of viruses with ______ capsids are arranged as a multifaceted polygon.
Helical; icosahedral
What term is used to describe the different host cells which a virus can infect?
Host range
A(n) _____ is a geometric viral form having 20 faces and 12 corners
Icosahedron
If the term "dead" is used to describe a particular bacterial cell, then the term ______ would be used to describe a virus in a similar condition.
Inactive
Viruses are best described as ______ rather than "dead"
Inactive
Through the process of _____ , a prophage is activated and enter the lytic cycle
Induction
Typically, naked helical viruses are _____ flexible than enveloped helical viruses.
Less
The term _________ is used to describe the physical rupture of a cell
Lyse
The term_____ (meaning rupturing) is used to describe how some viruses burst cells during the release stage of viral multiplication
Lysing
_____ is the persistence of bacteriophage DNA within a host chromosome
Lysogeny
What is the common name of bovine spongiform encephalophathy
Mad cow disease
A _______ virus does not have an envelope surrounding its capsid
Naked
what is the size unit that is best applied to viruses?
Nanometer
Which of the following terms is used to describe a viral RNA genome which cannot be immediately translated in protein
Negative-sense
The ________ refers to the capsid and the nucleic acid of a virus
Nucleocapsid
Viruses that are ______ lead to cancer in infected hosts
Oncogenic
____ is the term for a virus that can cause tumors
Oncovirus
Toxins of the bacteria responsible for diphtheria, cholera, and botulism are actually produced by:
Pathogens
_____ infections are those in which cells are infected yet cells are not immediately lysed
Persistent
The word "virus" comes from the latin word for _______
Poison
A(n) _____ is a proteinaceous infectious agent associated with spongiform encephalopathies
Prion
Which of the following is used to describe the phage DNA that is latently incorporated into the bacterial host genome?
Prophage
86. Capsomers are composed of _____ (hint: it is a macromolecule)
Protein
What is the best description of a prion?
Proteinaceous infectious agent
Prions are composed entirely of what molecules?
Proteins
A ________ is an animal virus which has integrated its DNA into the DNA of its host cell
Provirus
Viroids are composed of naked ____ strands
RNA
Viroids are composed or only naked ______
RNA
The virus buds off the membrane and picks up an envelope and spike in the _________ stage of the viral life cycle.
Release
HIV is described as a(n) ____ because it synthesizes DNA directly from RNA using reverse transcriptase.
Retrovirus
An enzyme capable of taking an RNA fenome and generating a DNA copy is called
Reverse transcriptase
Some laboratory animals can propagate viruses in the laboratory more readily than others because many viruses exhibit host ______
Specificity
Transmissible ______ encephalophathy is a disease condition of the brain caused by an infection with prions
Spongiform
Which of the following diseases are caused by prions
Spongiform encephalophathy
what is the purpose of vaccines
Stimulate host immune system
Viruses are classified based on genetic make up, chemical composition, and ______
Structure
_________ occur when a virus induces multiple cells to fuse, making a large multinucleated cell.
Syncytia
A ______ phage is a bacteriophage that incorporates itself into the host genome as a lysogenic prophage
Temperate
Some deadly human pathogens such as diphtheria, cholera, and botulism are made more virulent by bacteriophages known as ____ phages, or prophages
Temperate
Viral transformation by oncogenic viruses implies:
The host cell is changed
True or false: bacteriophages can increase the pathogenicity of their bacterial host
True
True or false: most viral infections do not result in death of the host organism
True
True or false: viral nucleic acid may be single-stranded or double-stranded DNA or RNA
True
True or false: viruses can contain either DNA or RNA but not both
True
The process of ______ occurs when viruses lose their capsid (and envelope, if they have one) during or after penetration into a host cell.
Uncoating
What is most important for attachment of a virus to a host cell?
Viral specificity for host receptors
Change in a cell line monolayer is indicative of what?
Virally infected cells
A fully formed infectious virus particle in a host cell is often called a(n) ________
Virion
What is completely composed of RNA?
Viroid
Identify the smallest pathogenic agent
Virus
What does "obligate" mean in regards to viruses?
Viruses must have a host cell
What is true about viruses?
all Viruses lack the machinery to synthesize proteins
Embryonic eggs:
are completely sterile
Plaques are associated with what?
bacteriophage infection of bacteria
The process of ________, a type of penetration, occurs when viruses are taken into the cell followed by engulfment in a vacuole or vesicle.
endocytosis
Identify the virus types which are released from the host cells by lysis
-Complex -Naked
How does T-even bacteriophage nucleic acid enter the host cell
Injection
Is it possible for a bacterial cell infected with a temperate phage to replicate?
Yes