Microbiology Ch. 6 Questions

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

Induction

"Virus" is Latin for :

Poison

A single virion could contain a genome of :

- DNA only - RNA only

Which four of the following are not found in viroids?

- Metabolic pathways - Mitochondria - Envelope - Capsid

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

- ssDNA - dsDNA - ssRNA

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

- ssDNA - dsDNA - ssRNA

Which two of the following mechanisms are found to result in cancer caused by a virus?

- viral proteins cause changes in growth proteins, resulting in cancer - the virus carries genes that can cause the cancer

Which of the following statements about virophages are correct? (p. 157)

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

Identify the commonalities between temperate phages and lytic phages :

- Adsorption - Penetration - Biosynthesis of viral components - Release - Assembly

Which three of the following steps are found in both animal virus life cycle and the bacteriophage life cycle?

- Assembly - Adsorption - Penetration

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

- Genetic makeup - Structure - Chemical composition

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

- Helical - Icosahedral

Identify any benefits of viruses to people :

- Some viruses control insect pests - Some viruses can be modified to deliver genetic cures - Some viruses control food pathogens

Host cells that have been transformed by an oncovirus will have which two of the following features?

- ability to divide indefinitely - changes in cell surface molecules

Identify the different environments in which some viruses can replicate :

- animal cells - human cells - bacterial cells

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

- change in cell shape - change in cell size

Identify which of the following statements represent activities that viruses CANNOT do.

- consume food - replicate outside of a cell

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

- fusion of viral envelope and cell membrane - engulfment/ phagocytosis of virus

Two shapes of viral capsids are ______, which resembles a bracelet; or ______, which is a type of polyhedron.

- helical - icosahedral

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

- naked - complex

At a minimum, a viral genome must include genes for :

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

Which two of the following statements regarding the human virome are true?

- some viruses are in a dormant state in the body - the human virome includes viruses that infect our commensal bacteria

Which facts best supports the position that viruses are not living organisms?

- viruses do not have any means of independent metabolism - viruses cannot reproduce on their own

What term is used to specifically describe the types of viruses that infect bacteria?

Bacteriophage

In describing the release of mature enveloped viruses from host cells, the terms exocytosis and ______ are interchangeable.

Budding

In which way do enveloped viruses leave their host cell?

Budding

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

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

Creutzfeldt-Jakob disease

Multinucleated cells, giant cells, and inclusion bodies are examples of ______ effects.

Cytopathic

The letters CPE stand for :

Cytopathic effect

Most RNA viruses will assemble the virion within the host cell's ______.

Cytoplasm

How does bacteriophage nucleic acid enter the host cell?

Injection

Typically, naked helical viruses are ______ flexible than enveloped helical viruses.

Less

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

Lysis

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

Lysogenic conversion

When a bacterium acquires a trait from its temperate phage, what has occured?

Lysogenic conversion

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

Lysogenic conversion

______ is the persistence of bacteriophage DNA within a lost chromosome.

Lysogeny

Which of the following denotes the genus of rabies virus?

Lyssavirus

The cell component indicated by the arrow is a :

Membrane receptor

The number of genes in a viral genome is ______ the number of genes in a bacterial genome.

Much less than

A non-enveloped virus is also called a(n) ______ virus.

Naked

Capsids of _____ helical viruses are rigid and tight while capsids of _____ helical viruses are flexible and loose.

Naked; enveloped

In this image of a nucleocapsid, the macromolecule comprising the structure indicated by the arrow is :

Nucleic acid

The ______ refers to the capsid and nucleic acid of a non-enveloped virus.

Nucleocapsid

Most animal viruses with a DNA genome will assemble their virions within the host cell's :

Nucleus

Viruses that are ______ lead to cancer in infected hosts.

Oncogenic

The largest known virus, the ______, discovered in 2013, is as big as the Streptococcus bacterium and is visible in a light microscope.

Pandovirus

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

Persistent

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

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

Capsomers are composed of ______.

Protein molecules

Which of the following best describes a prion?

Proteinaceous infectious agent

At minimum, all viruses are composed of :

Proteins - all viruses will have a capsid which is composed of proteins that surrounds their nucleic acids Nucleic acids - all viruses have a type of nucleic acid as a heritable material for their replication

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

Provirus

Viroids are composed of naked ______ strands.

RNA

When it comes to virus multiplication, viral exocytosis refers to ______.

Release

In a chronic latent state, a virus will :

Remain dormant in cell for years

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

Retroviruses

In some viruses, including HIV, the enzyme ______ ______ transcribes RNA into DNA.

Reverse transcriptase

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

Reverse transcriptase

A noncellular infectious form that depends on other viruses for replication is known as a(n) ______ virus.

Satellite

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

Significantly

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

Spikes

Transmissible ______ encephalopathy is a disease condition of the brain caused by an infection with prions.

Spongiform

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

Syncytium

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

Temperate

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

Uncoating

Which is most important for attachment of a virus to a host cell?

Viral specificity for host receptors

A single virus particle is called what?

Virion

Cytomegalovirus, Epstein-barr viruses, bacteriophages, and the remainder of the approximately 10^15 viruses associated with a typical adult can collectively be referred to as that individual's :

Virome

A(n) ______ is a microscopic, acellular agent composed of nucleic acid surrounded by a protein coat.

Virus

Most bacteriophages contain what type of nucleic acid?

dsDNA

T/F = Most active viral infections lead to cell death regardless of the type of release process.

True

T/F = Noncellular infectious agents other than viruses are medically important.

True

T/F = Viral nucleic acid may be single-stranded or double-stranded DNA or RNA.

True

A(n) ______ is an infectious agent that lacks a capsid and merely consists of a strand of RNA.

Viroid

The arrow is pointing to a bacteriophage component called the :

Capsid

Identify any of the following pathways which could produce proteins used by viruses :

1) Host DNA --> mRNA --> proteins used by viruses - this is akin to mRNA and therefore can be immediately translated into protein 2) Viral positive-ssRNA --> proteins used by viruses - some host proteins are used by viruses for viral multiplication; host DNA polymerases might be used to replicate viral DNA

Order the following entities by average size, from smallest to largest, starting with the smallest at the top :

1) virus 2) bacterial cell 3) yeast cell

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

1. Absorption 2. Penetration/Uncoating 3. Synthesis 4. Assembly 5. Release

The smallest animal virus, parvovirus, is approximately what size?

20 nanometers

The viral nucleic acid is indicated by the letter :

A

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

Adsorption

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

Adsorption - means to adhere

During the ______ step in viral multiplication, capsids and genetic material are packaged into virus particles.

Assembly

Which of these images illustrates viral penetration by membrane fusion?

B

In this image of an enveloped virus, the structure labeled with the arrow is the :

Capsid

The structure directly surrounding the viral nucleic acid is the ______, a coat of proteins.

Capsid

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

Capsid

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

Capsomere

The structure represented here as the protein subunit of a helical capsid is termed a :

Capsomere

Viruses ______ depends on a host cell for replication.

Completely

T/F = Viruses are among the smallest infective agents.

True

T/F = Most infections caused by animal viruses do not result in death of the host organism.

True - generally nonlethal

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

Endocytosis

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

Envelope

T/F = most bacteria engulf bacteriophages as part of the phage replication stage.

False

The syncytium illustrated in this image is the result of the virus' ability to :

Fuse membrane

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

Genome

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

Glycoproteins

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

Host

A(n) ______ is a geometric viral form having 20 faces and 12 corners.

Icosahedron

Capsid structure which has 20 panels of capsomers arranged in a symmetrical pattern is called an ______.

Icosahedron

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

Inclusion body

______ is when a phage transfers genes between bacteria.

Transduction

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

Transformation

A positive-sense RNA genome is ready for immediate :

Translation to protein

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

Tropism

T/F = All viruses must infect a host cell in order to replicate.

True