Microbio ch. 6 learnsmart

Which two of the following statements about virophages are correct?

-uses genes from another virus for its own replication. -a virus that parasitizes another virus.

List the correct order of viral life cycle phases, starting with the first at the top.

1.Adsorption 2. Penetration/ uncoating 3. Synthesis 4. Assembly 5. Release

Which is the correct term to describe viral adherence to a host cell receptor?

Adsorption

Which viral stage occurs first?

Adsorption

_______is the viral process of attaching to the host cell receptor for the virus.

Adsorption

Identify the different environments in which some viruses can replicate.

Bacterial cells Human cells Animal cells

Any virus that specifically infects bacteria is called a(n)

Bacteriophage or phage

Identify prion related diseases.

Bovine spongiform encephalopathy, Creutzfeldt-Jakob disease

Which is closest in physical proximity to the nucleic acid of a virus?

Capsid

Which structure immediately encloses viral nucleic acid?

Capsid

Which of the following is the monomeric unit for a viral capsid?

Capsomere

Which two of the following are cytopathic effects in virally infected animal cells?

Change in cell shape and Change in cell size

Which prion-associated spongiform encephalopathy is marked by dementia, impaired senses, and uncontrolled muscle contractions?

Creutzfeldt-Jakob disease

Where are most RNA viruses replicated and assembled within the host?

Cytoplasm

Identify all the methods that a virus can use to gain entry into an animal cell.

Engulfment/phagocytosis of the virus 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

True or false: Chicken eggs have a monolayer of cells within them which offer a good place to propagate virus.

False

True or false: Most bacteria engulf bacteriophages as part of the phage replication strategy.

False

True or false: Viruses which can lead to cancer are termed carcinoviruses.

False Oncogenic or oncoviruses

The viral envelope and capsid are the same thing.

False The viral envelope is composed of phospholipids while the capsid is composed of capsomer proteins.

Which are the three main criteria used in classifying viruses into families?

Genetic makeup, Structure, Chemical composition

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 *Negative RNA strands must be transcribed into positive sense strands before they can be translated into proteins.

Which of the following is a term used to describe the different host cells which a virus can infect?

Host range

Which of the following is a mass of viruses or damaged organelles due to the cytopathic effect of viral infection?

Inclusion Body

Which two of the following are cytopathic effects in virally infected animal cells

Inclusions and Syncytia

What term is used to define the process of a prophage being activated and entering into the lytic cycle?

Induction

How does bacteriophage nucleic acid enter the host cell?

Injection

Which of the following describes a bacteriophage-mediated process by which bacteria gain genes enhancing their ability to cause human disease?

Lysogenic conversion

Which term refers to the persistence of bacteriophages within host cells?

Lysogeny

Identify the virus types which are released from host cells by lysis.

Naked and Complex

Identify all the components of the nucleocapsid.

Nucleic acid Capsid

Where are most DNA viruses replicated and assembled within the host?

Nucleus

Which of the following best describe the relationship between viruses and their host cell?

Parasitism

A cell harboring a virus that is not causing cytopathic effects is characteristic of which type of infection?

Persistent infection

______ infections are those which cells are infected yet show no cytopathic effects.

Persistent or Latent

"Virus" is Latin for

Poison

______is a name given to a disease-causing agent composed only of protein.

Prion

Which of the following is used to describe the phage DNA that is latently incorporated into the bacterial host genome?

Prophage

At minimum, viruses are composed of nucleic acid covered by a coating comprised of

Protein

:Which of the following best describes a prion?

Proteinaceous infectious agent

Prions are composed of what molecule?

Proteins

Which macromolecule composes capsomeres?

Proteins

At minimum, all viruses are composed of

Proteins Nucleic acids

Which of the following describe an animal virus that has integrated its genome into the host cell's genome?

Provirus

__________ is the stage of an animal virus life cycle which is integrated into the host cell's genome.

Provirus

In animal viruses, newly made _______ is used to synthesize viral proteins.

RNA or mRNA

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

Which of the following structures of enveloped viruses must be specific for adsorption?

Spike proteins

What term is used to describe the viral proteins which protrude from the envelope and aid in attachment to host receptors?

Spikes

Viruses are classified into families based on genetic makeup, chemical composition, and ______.

Structure

Which of the following is a multinucleated mass of cells due to the cytopathic effect of viral infection?

Syncytium

What name is given to a phage "type" which can incorporate itself into the host genome as a lysogenic prophage?

Temperate

Which process involves gene recombination via bacteriophage transfer?

Transduction

Which term describes the integration of an oncogenic virus that changes mammalian host DNA?

Transformation

A virus that only infects cells of a specific tissue in the body is described as having a ______.

Tropism

True or false: Embryonic tissue can serve as a primary cell line for viral culture.

True

True or false: Inoculation of laboratory animals is an in vivo method of viral cultivation.

True

True or false: 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

Which of the following statements regarding the membrane on an enveloped virus is true?

Viruses insert their own proteins in the membrane.

Which of the following describes the various viral parts coming together to produce virions?

assembly

During the step in the viral multiplication cycle, capsids and genetic material are packaged into virions.

assembly or maturation

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

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; lysis or cell lysis

Some retroviruses carry oncogenes that may incorporate into the host cell DNA and ultimately result in ______.

cancer

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 or nucleocapsid

A(n) _________ is a protein subunit that forms the viral capsid.

capsomere

Viruses ______ depend on a host cell for replication.

completely

Most bacteriophages have _______ -stranded DNA genomes

double

Most bacteriophages contain which type of nucleic acid?

dsDNA

A single virion could contain a genome of

either DNA only or RNA only

Viral nucleic acids are ______.

either single-stranded or double stranded

The process of _______, a type of penetration, occurs when viruses are taken into the cell followed by engulfment in a vacuole or vesicle.

endocytosis or phagocytosis

A(n) __________ virus has a membranous layer external to the nucleocapsid.

enveloped

Budding is a type of ______ process where enveloped viruses are released from the host cell membrane.

exocytic

The total nucleic acid content of a virus can be referred to as the viral _____

genome or DNA

The membrane receptors that viruses attach to during adsorption are 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; icosahedral or icosahedron

The ______ range defines the limitations of the type of cell that a virus can invade.

host

Viral transformation implies ______.

host DNA is changed

______ bodies are masses of viruses or damaged organelles of a cell due to a cytopathic effect of viral infection.

inclusion

______bodies are masses of viruses or damaged organelles of a cell due to a cytopathic effect of viral infection.

inclusion

Through the process of _______ , a prophage is activated and enters the lytic cycle.

induction

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

Which term correctly refers to viral bursting of any host cell?

lysis

When a bacterium acquires a new trait from a temperate phage, ______ conversion has occurred.

lysogenic

The process by which bacteriophages infect bacteria, conferring new traits enhancing human disease, is called ______.

lysogenic conversion

When a temperate phage infects a bacterium which gives the bacterium new traits, this is called ______.

lysogenic conversion

Somatic human cells undergo _____ , a type of cell division, to produce new cells.

mitosis

Primary cells undergo which type of division to produce a monolayer for animal virus culture?

mitotic

_____ active viral infections lead to cell death.

most

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

The ________ refers to the capsid and nucleic acid of a nonenveloped virus.

nucleocapsid

At a minimum, a viral genome must include genes for

packaging the mature virus particles synthesizing the viral capsid regulating the actions of the host cell

A(n) _________ 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 ______.

protein

HIV is described as a(n) _______ 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

Most human viral infections are ______.

self-limiting

:When an enveloped virus buds off the cell membrane, the membrane differs ______ from the host cell's membrane.

significantly

Viral glycoproteins that protrude from the viral envelope and attach to host cell receptors are termed

spikes, peplomers, or glycoprotein spikes

Identify all the types of nucleic acid genomes which have been discovered carried by various bacteriophages.

ssDNA ssRNA dsDNA

A _________ occurs when a virus induces multiple cells to fuse making a large multinucleated cell.

syncytium or syncytia

A virus that parasitizes another virus is called a(n) ______.

virophage

The term "in ______" implies that a virus is being propagated in a living animal.

vivo

A ______ phage is a bacteriophage that incorporates itself into the host genome as a lysogenic prophage.

temperate

_______is when a phage transfers genes between bacteria.

transduction

Both naked and complex viruses are released from host cells via lysis once mature.

true

True or false: Bacteriophages can contain double-stranded or single-stranded DNA or RNA.

true

A single virus particle is known as a(n) _______.

virion