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