Micro Ch 6 Part 1
____ microscopes are commonly used to view viruses.
Electron
Which term is used to describe the process when a virus is engulfed by a cell in a vacuole or vesicle?
Endocytosis
Which parts of viral anatomy may play a direct role in adsorption?
Envelope, capsid
Generally, which of the following accurately describes LARGEST to SMALLEST.
Eukaryotic cell> bacteria > virus > protein
True or false: The capsid of all viruses is protected by an external envelope.
False
True or false: Viral DNA, but not viral RNA, can be double-stranded.
False
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 of the following denotes the family name of the HSV-1?
Herpesviridae
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
What term is used to define the process of a prophage being activated and entering into the lytic cycle?
Induction
Which is NOT a type of lethal damage to cells caused by active viral infections?
Integration of viral DNA into host chromosome
Which term refers to the persistence of animal viruses within host cells with periods of inactivity?
Latency
Which term refers to the physical rupture of a cell?
Lysis
Identify the virus types which are released from host cells by lysis.
Naked, complex
Which two techniques are used to enhance viewing of viruses under electron microscopy?
Negative staining, shadowcasting
Which of the following characteristics are correct of viruses?
Obligate intracellular agents, acellular, infects very specific cell types
Which type of viruses integrate and change host DNA, leading to cancer?
Oncogenic
Identify which of the following are reliant on the viral capsid.
Penetration, adsorption
____ infections are those which cells are infected yet show no cytopathic effects.
Persistent
Which is an enzyme that joins monomers, or building blocks, to form larger molecules?
Polymerase
Which of the following is used to describe the phage DNA that is latently incorporated into the bacterial host genome?
Prophage
What is the primary function of the viral capsid and envelope?
Protection
What functions do capsid proteins perform for naked viruses?
Protection, attachment
Which structure is more rigid (not flexible)?
Protein-protein interactions of capsomer binding to form the capsid
Which of the following activities are NOT characteristic of viruses?
React to environmental factors, metabolize food, replicate independently, maintain homeostasis.
The viral genome must possess genes for which of the following?
Regulation of host cell action, synthesis of capsid, packaging of new virions, synthesis of viral genome
When it comes to virus multiplication, viral exocytosis refers to
Release
Which of the following is a hallmark characteristic of all viruses?
Requires a host cell for replication
Which preformed enzyme is involved in the synthesis of DNA from RNA in a retrovirus like HIV?
Reverse transcriptase
Which viral enzyme is responsible for converting a RNA genome into a DNA genome?
Reverse transcriptase
____-casting is a microscopy technique that uses metallic vapors directed at the virus specimen to enhance its appearance.
Shadow
Which of the following describes the size of most viruses?
Smaller that 0.2 micrometers
Which of the following viral structures must be specific for adsorption?
Spike proteins
Which best describe the shape of a helical virus?
Spiral
Which are the 2 main criteria used in classifying viruses into families?
Structure, genetic makeup
What name is given to a phage "type" which can incorporate itself into the host genome as a lysogenic prophage?
Temperate
The cause of viral infections remained unknown for many years longer than other types of infections because:
The techniques used to observe other pathogens were useless with viruses, viruses are not visualized by light microscopes
Which term describe the integration of an oncogenic virus that changes mammalian host DNA?
Transformation
____ are tissue specificities of animal viruses for certain body cells.
Tropisms
True or false: "Persistent infections" could last weeks, years, or even the life of an infected person.
True
True or false: In persistent infections, viruses are in the carrier or latent state within host cells.
True
True or false: Temperate phages do not immediately lyse or change the appearance of host cells.
True
True or false: Viruses can be manipulated to infect cells they would not normally infect for purposes of laboratory cultivation.
True
True or false: Viruses can contain either DNA or RNA, but not both.
True
True or false: viral nucleic acid may be single-stranded or double-stranded DNA or RNA.
True
Which is FALSE regarding the viral envelope and the membrane of its host?
Viral glycoproteins are present in the host membrane but not in the viral envelope.
Which is most important for attachment of a virus to a host cell?
Viral specificity for host receptors
Which of the following would occur during the viral propagation phase known as "Assembly"?
Viral spike proteins embed in the cell membrane
Which of the following is probably the least responsive to the environment?
Virus
Which of the following is the smallest in relative size?
Virus
Which type of microbes are considered the most abundant on earth?
Viruses
Which best explains why viruses have so few genes?
Viruses do not have metabolic pathways
A viral ____ can give an altered appearance of an icosahedral virus.
envelope
Viruses that have a(n) ____ will be released by budding.
envelope
A(n) ____ virus has a membranous layer external to the nucleocapsid.
enveloped
In describing the release of mature enveloped viruses from host cells, the terms ____ and budding are interchangeable
exocytosis
When it comes to virus classification, there are seven orders of viruses compared to the 96 virus ____ and 350 genera.
families
Typical viruses contain ____ number of genes compared to bacteria.
fewer
Viruses are parasitic and must enter cells to take over the ____ material of their host in order to reproduce.
genetic
The total nucleic acid content of a virus can be referred to as the viral ____.
genome
Viruses which have a series of capsomer proteins linked together forming a barrel is termed ____.
helical
The two shapes of capsids are ____ and ____, which is a type of polyhedron
helical; icosahedral
Viruses with a ____ capsid have rod-shaped capsomers, while the capsomers of viruses with ____ capsids are arranged as a multifaceted polygon.
helical; icosahedral
The length of a viral multiplication cycle is usually 8-72:
hours
A viral capsid structure which has 20 panels of capsomers arranged in a symmetrical pattern is called ____.
icosahedral
Viruses which have symmetrical polygonal capsids are called ____.
icosahedral
A(n) ____ is a geometric viral form having 20 faces and 12 corners.
icosahedron
When viruses exposed to compounds or UV-light which makes them non-infectious, then they are called:
inactive
Lysogeny is best described as
integration of the viral genome into the host chromosome
All viruses are
intracellular, obligate, parasitic
Some chronic diseases are due to ____ viruses that persist in animal host cells.
latent
Typically, naked helical viruses are ____ flexible than enveloped helical viruses.
less
The principle macromolecule which composes the viral envelop are ____.
lipids
Bacterial host cells undergo ____ due to the splitting open and release of bacteriophages.
lysis
Naked viruses are released from animal cells by ____.
lysis
The term ____ (meaning rupture) is used to describe how some viruses burst cells during the release stage of viral multiplication.
lysis
The term ____ refers the the persistence of bacteriophages within host cells.
lysogeny
A ____ virus does not have an envelope surrounding its capsid.
naked
Capsids of ____ helical viruses are rigid and tight, while capsids of ____ helical viruses are flexible and loose.
naked; enveloped
Viruses with single-stranded RNA genomes that have to be converted to the "other strand of RNA" before it can be translated into protein are called ____-strand RNA viruses.
negative
The term "naked" used in describing viruses implies
no lipid envelope
Viruses are
non-living, infectious angent
Most DNA viruses will assemble their virions within the host cell's ____.
nucleus
Viruses that are ____ lead to cancer in infected hosts.
oncogenic
Viruses which can lead to cancer are called
oncoviruses
When it comes to virus classification, there are seven ____ of viruses compared to the 96 virus families and 350 genera.
orders
The word virus is Latin for ____.
poison
The enzyme ____ is a preformed viral enzyme that synthesizes the viral nucleic acids.
polymerase
The internal details of viruses are revealed by ____ staining techniques.
positive
Viruses with single-stranded RNA genomes that can be directly translated into proteins are called ____ strand RNA viruses?
positive
The ____ are a group of complex viruses that lack a typical capsid and are covered by a dense layer of lipoproteins and fibrils.
poxviruses
Capsomers are composed of ____.
protein
HIV is described as a(n) ____ it synthesizes DNA from RNA and using reverse transcription.
retrovirus
Enveloped viruses use ____ made of glycoproteins, for absorption to host cells.
spikes
Most viral ____ in the capsid or envelope are composed of glycoproteins and used to attach to host cells.
spikes
The ____ of a virus are protruding glycoproteins, responsible for binding to a host cell.
spikes
A ____ occurs when a virus induces multiple cells to fuse making a large multinucleated cell.
syncytia
Typically, one virus enters a host cell and out comes viruses in the
thousands
The prefix "____"-microscopic describes the relatively small size of most viruses.
ultra
The process of ____ occurs when viruses lose their envelope during penetration into a host cell or when the envelope/capsid are dissolved within a vacuole.
uncoating
The viral envelope is compositionally different form a non-infected host cell because of the presence of ____.
viral proteins
If a yeast cell is larger than a bacterial cell, then bacteria are larger than ____.
viruses
Rank the following form SMALLEST genome to LARGEST genome.
1. Virus 2. Bacterium 3. Eukaryotic cell
How many facets are there in an icosahedral virus?
20
Most animal viruses are ____ in size.
20-1000 nm
Identify all the components of the nucleocapsid.
Capsid, nucleic acid
Some viruses bud from which of the following cellular compartments?
Cell membrane, nucleus, endoplasmic reticulum
Which contains DNA and RNA simultaneously?
Cells only
Viruses are composed of which of the following?
DNA or RNA, protein capsid
In which way do enveloped viruses leave their host cell?
Budding
Which suffix represents a viral genus?
-virus
List the correct order of viral life cycle phases.
1. Adsorption 2. Penetration/Uncoating 3. Synthesis 4. Assembly 5. Release
Which of the following relate to viruses?
Acellular, capsid, nucleic acid
What term is used to describe when a virus initially "sticks" to the host cell?
Adsorption
____ is the viral process of attaching to the host cell receptor for the virus.
Adsorption
The viral capsid or viral proteins embedded in the envelope promotes production of which of the following by the host?
Antibody
Which of the following describes the process of various viral "parts" coming together to produce complete virons?
Assembly
Identify the different environments in which some viruses can replicate.
Bacterial cells, human cells, animal cells.
What term is used to describe viruses which infect bacteria?
Bacteriophages
Which scientist proposed the term "virus"?
Beijernick
Viruses which have envelopes are considered ____.
acellular
Most enveloped viruses are
animal
During the ____ step in the viral multiplication cycle, the genetic material is packaged into capsids to make virions.
assembly
Exocytosis, or ____, of enveloped viruses occurs from the host cell membrane during the release stage of the viral multiplication cycle.
budding
Mature enveloped viruses are released from host cells via ____ or exocytosis.
budding
Viruses that are released from a cell by ____ will not initially destroy the cell.
budding
The structure directly surrounding the viral nucleic acid is the ____, a coat of proteins.
capsid
A(n) ____ is a protein subunit that forms the viral capsid.
capsomer
A general concept of all viruses is that they require a host ____ in order to replicate.
cell
The word ____ is used to describe viruses which have a non-icosahedral or non-helical arrangement of capsomer proteins.
complex
Multinucleated cells, giant cells, and inclusion bodies are examples of ____ effects.
cytopathic
The term ____ refers to "cell disease."
cytopathic
Using a microscope, you observe some cells which have multiple nuclei because a virus has caused normal cells to fuse together. This observation is termed
cytopathic effect
The acronym CPE stands for ____ ____.
cytopathic effects
Most RNA viruses will assemble the virion within the host cell's ____.
cytoplasm
Identify all the types of nucleic acid genomes which have been discovered carried by various bacteriophages.
dsDNA, ssDNA, ssRNA
Viruses which have DNA genomes are
either single stranded or double stranded