MCB CH 6

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

Adsorption

Which of the following is a common feature of continuous cell lines? No mutations, normal morphology Continuous growth Meiotic division

Continuous growth

Which term describes a nonliving microscopic agent?

Infectious particle

When phage nucleic acid is incorporated into the nucleic acid of its host cell and is replicated when the host DNA is replicated, this is considered part of which cycle? Cell cycle Multiplication cycle Virulence cycle Lysogenic cycle Lytic cycle

Lysogenic cycle

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

Lysogeny

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

Lysogeny Lysogeny refers to temperate bacteriophages while latency refers to the persistence of animal viruses.

Identify the commonalities between temperate phages and lytic phages. Integration of the viral genome into the host genome Release Biosynthesis of viral components Penetration Adsorption Assembly

Release Biosynthesis of viral components Penetration Adsorption Assembly

Which type of phage generally can increase the pathogenicity of a bacterium?

Temperate phage

Select the three choices which are the primary purposes of cultivating viruses.

To isolate viruses from clinical specimens To prepare viruses for vaccines To research the biology of viruses

Which term describes the process of a virus losing its capsid and exposing viral nucleic acids to the immediate environment?

Uncoating

Which type of capsids are composed of multiple protein types and nonsymmetrical shapes?

complex

The two principal processes by which viruses penetrate host cells are _________ (engulfment) and direct fusion.

endocytosis

True or false: Primary cell cultures are naturally long-lived or immortal.

false- Primary cell lines can mutate into continuous cell lines that exhibit immortality.

The membrane receptors that viruses attach to during adsorption are typically composed of ______.

glycoproteins

What are the viral spikes typically composed of?

glycoproteins

Viruses with a _____ capsid have rod-shaped capsomers, while the capsomers of viruses with _______ capsids are arranged as a multifaceted polygon

helical icosahedral

Viral transformation implies ______.

host DNA is changed

Viruses which have symmetrical polygonal capsids are called ______.

icosahedral

Which Latin phrase describes the cultivation or testing "in glass" or outside of a living organism?

in vitro In vivo means "in life" or in the living organism.

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

nucleocapsid

Phage DNA that is latently incorporated into the bacterial host genome is called a

prophage

True or false: The interior of eggs normally contains non-pathogenic bacterial flora but no viruses.

False The interior of eggs is normally a sterile environment and free from any type of microbes or viruses.

______ viruses in the human body are pathogenic. Most All Few None

Few

Different viruses can infect which of the following? Human cells only Bacterial cells only Human, bacterial, or plant cells Plant cells only

Human, bacterial, or plant cells

Which Latin phrase describes the cultivation or testing within a living organism?

In vivo In vitro means "in glass" or in a test tube.

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

Induction

What was the significance of the discovery of filterable viruses? It demonstrated that infections could only be caused by cellular, rather than acellular, microbial agents. It demonstrated that infections could be caused by agents that were smaller than bacteria. It demonstrated that viruses could infect bacteria.

It demonstrated that infections could be caused by agents that were smaller than bacteria.

Which of the following would you expect to see from bacteriophage propagation? Lesion Clumping of cells Multinucleated cells Plaques

Plaques

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

Prophage

Which of the following best describes a prion? Proteinaceous infectious agent RNA-based infectious agent Obligate aerobe Obligate intracellular parasite

Proteinaceous infectious agent

What are viruses called which are capable of converting their RNA genomes into DNA?

Retroviruses

Which of the following is an enzyme found in HIV that is responsible for converting its RNA genome into a DNA genome? Reverse polymerase Auto convertase Reverse transcriptase Retro transcriptase

Reverse transcriptase

What term is used to describe a virus type which depends on other viruses for replication? Eclipse virus Satellite virus Temperate virus Rho-dependent virus

Satellite virus

Which two of the following statements regarding the human virome are true? Some viruses are in a dormant state in the body. Most viruses in the human virome are pathogenic. The human virome includes viruses that infect our commensal bacteria. Only a few cell types in the human body are susceptible to viru

Some viruses are in a dormant state in the body. The human virome includes viruses that infect our commensal bacteria.

Transduction leads to which important consequence? Multiple choice question. Increased side effects to antiviral drugs in the patient Spread of drug resistance in bacteria Decreased immunity in the host

Spread of drug resistance in bacteria

True or false: Viruses cannot be called organisms.

True: The word organism infers the qualities of "life" and viruses are not living.

Select the three methods that are used to cultivate viruses.

Use of cell culture techniques Use of animal inoculation Inoculation of embryonated eggs

What does "obligate" mean in regard to viruses? Viruses are infectious Viruses are airborne Viruses must have a host cell Viruses are composed of proteins and nucle

Viruses must have a host cell

List the correct order of viral life cycle phases, starting with the first at the top. synthesis release assembly adsoption penetration/uncoating

adsoption penetration/uncoating synthesis assembly release

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

adsorption

It is well known that have _________ no effect on treating viral infections.

antibiotics

Embryonic eggs ______. are completely sterile have a few non-pathogenic bacteria

are completely sterile

Which of the following describes the various viral parts coming together to produce virions? Assembly Absorption Release Penetration

assembly

During the __________ step in the viral multiplication cycle, capsids and genetic material are packaged into virions. Please give the specific term for this step.

assembly/maturation

Mature enveloped viruses are released from host cells via ________ or exocytosis.

budding

The word __________ is used to describe viruses which have a non-icosahedral or non-helical arrangement of capsomer proteins.

complex

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

cytoplasm

Most bacteriophages have _______ -stranded DNA genomes.

double

Most bacteriophages contain which type of nucleic acid?

dsDNA

This micrograph illustrating viruses documents that the best method for viewing viruses is

electron microscope

Which term is used to describe the phospholipid bilayer found surrounding the capsid of some viruses?

envelope

Which types of viruses are released by budding? RNA viruses Enveloped viruses DNA viruses Naked viruses

enveloped

Which two of the following are cytopathic effects in virally infected animal cells? Prions Inclusions Viroids Syncytia

inclusions syncytia

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

induction

Which of the following terms is used to describe a viral RNA genome which CANNOT be immediately translated into protein? Neutral Negative-sense Transcription Positive-sense

negative sense

Where are most DNA viruses replicated and assembled within the host? rough er cytoplasm dna

nucleus dna replicated in nucleus for host cells

Which three of the following steps are found in both the animal virus life cycle and the bacteriophage life cycle? Multiple select question. penetration uncoating adsorption assembly oncogenesis

penetration adsorption assembly

A(n) ________ is a proteinaceous infectious agent associated with spongiform encephalopathies.

prion

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

spikes

True or false: Bacteriophages can increase the pathogenicity of their bacterial host.

true

True or false: Both naked and complex viruses are released from host cells via lysis once mature.

true

True or false: Viral nucleic acid may be single-stranded or double-stranded DNA or RNA.

true

True or false: Interferons are naturally produced during some viral infections.

true- Interferons are produced by cells in response to many types of viral infections.

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 of the following steps of the animal virus life cycle is not found in the bacteriophage life cycle? assembly lysis penetration uncoating adsorption

uncoating

A fully formed virus that is able to establish an infection in a host cell is often called a ______.

virion

A single virus particle is known as a(n)

virion

Identify the different environments in which some viruses can replicate. Bacterial cells Animal cells Human cells Marine water Freshwater

Bacterial cells Animal cells Human cells

______ phages enter the prophage state, while ________ phages burst the host cell.

Blank 1: Temperate or Lysogenic Blank 2: lytic, virulent, or T-even

Identify all the components of the nucleocapsid. Scaffolding proteins Polymerase Envelope Capsid Nucleic acid

Capsid Nucleic acid

Which two of the following are cytopathic effects in virally infected animal cells? Change in cell shape Appearance of plaques Change in cell size Production of viroids

Change in cell shape Change in cell size Reason: Plaques are associated with virally infected bacterial cells.

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

Complex Naked

A single virion could contain a genome of

DNA only RNA only

Identify all the methods that a virus can use to gain entry into an animal cell. Engulfment/phagocytosis of the virus Injection of viral nucleic acids across the cell membrane Fusion of the viral envelope and the cell membrane

Engulfment/phagocytosis of the virus Fusion of the viral envelope and the cell membrane Not Injection of viral nucleic acids across the cell membrane Reason: This is the method used by bacteriophages but bacteriophages cannot infect animal cells.

True or false: "Transduction" has been linked to the spread of antibiotic resistance in bacteria.

t- Reason: Transduction is the process during which a phage is released from a bacterial cell but it carries a portion of the host cell's genome rather than viral genes and infects a new cell. The phage could bring with it antibiotic resistant genes to the new bacterial cell.

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

temperate

A bacteriophage that incorporates itself into the host genome as a lysogenic prophage is called a(n) ______phage.

temperate

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

transformation

Lysogeny is best described as ______. lysis of the host cell replication of virions fragmentation of the host chromosome integration of the viral genome into the host chromosome

integration of the viral genome into the host chromosome

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

lysogenic

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

lysogenic conversion

In a chronic latent state, a virus will ______. rely on host ribosomes to make its proteins remain dormant in cells for years lose its glycoprotein spikes adsorb to many different cell types

remain dormant in cells for years

HIV is described as a(n) ________ because it synthesizes DNA from RNA using reverse transcription.

retrovirus

An enzyme capable of taking an RNA genome and generating a DNA copy is called ______. retro transcriptase reversable genetics reverse translation reverse transcriptase

reverse transcriptase

The enzyme _______ ________ is a preformed protein carried in by HIV responsible for converting its RNA genome into DNA.

reverse transcriptase