Exam 3

Nucleic acids Proteins

At minimum, all viruses are composed of Carbohydrates Lipids Nucleic acids Proteins

viral

Genes for synthesizing the viral capsid, for regulating actions of the host cell, and for packaging the mature virus are found in the ______ genome. bacterial viral eukaryotic

Nucleic acid Capsid

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

Virion

Identify the smallest pathogenic agent. Virion Bacterial cell Helminth Fungal cell

prophage

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

either single-stranded or double stranded

Viral nucleic acids are ______. single-stranded only if RNA double stranded only single-stranded only either single-stranded or double stranded

cytopathic effect

Virus-induced damage to the cell that alters its microscopic appearance is termed ______. cellular persistent effect cytopathic effect cellular pathogenic effect cytopathogenic effect

completely

Viruses ______ depend on a host cell for replication. completely never partially

adsorption assembly penetration

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

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

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. Only a few cell types in the human body are susceptible to viruses. Most viruses in the human virome are pathogenic.

Inclusion

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

virus

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

provirus

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

syncytia

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

virion

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

virion

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

naked

A nonenveloped virus is also called a(n) ______ virus. helical icosahedral naked

translation to protein

A positive-sense RNA genome is ready for immediate ______. replication to negative-sense RNA translation to protein replication to DNA reverse transcription to DNA

chronic latent

A virus may persist in cells in an inactive state for long periods, and are said to be in a ______ state. enveloped transformed chronic latent chronic distressed

viroid

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

phage

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

retrovirus

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

Engulfment/phagocytosis of the virus Fusion of the viral envelope and the cell membrane

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

Release Biosynthesis of viral components Penetration Assembly Adsorption

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

Virion

Identify the smallest pathogenic agent. Bacterial cell Helminth Fungal cell Virion

Naked Complex

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

remain dormant in cells for years

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

Cow

In the disease condition known as bovine spongiform encephalopathy, what does "bovine" mean? Cow Brain Liver A region of the spine

antibiotics

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

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

Select all that apply At a minimum, a viral genome must include genes for synthesizing new ribosomes following infection regulating the actions of the host cell packaging the mature virus particles generating ATP for energy synthesizing the viral capsid

Bovine spongiform encephalopathy Creutzfeldt-Jakob disease

Select all that apply Identify prion related diseases. Bovine spongiform encephalopathy Lyme disease Creutzfeldt-Jakob disease primary amebic meningoencephalitis

Envelope Capsid Metabolic pathways Mitochondrion

Select all that apply Which four of the following are not found in viroids? Envelope Capsid Metabolic pathways Mitochondrion Nucleic acid

Change in cell shape Change in cell size

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

Inclusions Syncytia

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

RNA only DNA only

Select all that apply. A single virion could contain a genome of both RNA and DNA RNA only neither RNA or DNA DNA only

the phage DNA is injected directly into the cell cytoplasm

The bacteriophage life cycle does not have a step for uncoating because ______. phage particles mature directly in the cell cytoplasm the phage DNA is injected directly into the cell cytoplasm bacteriophage often become lysogenic cell lysis is inevitable as the bacteriophage mature

syncytia

The cytopathic effect illustrated in this image is the formation of ______. infectious virions double-stranded DNA syncytia inclusion bodies

CPEs

The initials _____ are used for cytopathic effect.

enveloped

The maturation process illustrated here is for a(n) ______ virus. naked crystalline enveloped

virus

The mature virus component indicated by the arrow is encoded in the genome of the ______. virus host cell

the entire virus enters an animal cell, but only phage DNA enters a bacterial cell

The penetration step differs between animal viruses and bacteriophage in that ______. bacteriophage are required to initiate a productive infection of a bacterial cell the entire virus enters an animal cell, but only phage DNA enters a bacterial cell the size difference between the two virus types dictates that animal viruses must enter by endocytosis

lysogenic cycle

The process illustrated here is termed ______. viral tranformation lytic cycle lysogenic cycle uncoating

exocytosis

The process of releasing mature virus particles as illustrated here is termed ______. engulfment transcription adsorption exocytosis

capsid

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

a bacteriophage genome inserted in the bacterial chromosome

The structure indicated by the arrow in this image represents ______. bacteriophage particle that has been endocytosed and uncoated in the cytoplasm a bacteriophage genome inserted in the bacterial chromosome a bacterial ribosome synthesizing bacteriophage proteins the nucleus of the bacterial cell

fuse membranes

The syncytium illustrated in this image is the result of the virus' ability to ______. change cell shape fuse membranes form inclusion bodies change cell size

A

The viral nucleic acid is indicated by the letter ______. C B D A

induction

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

False

True or false: All noncellular infectious agents are morphologically similar to viruses.

True

True or false: Most active viral infections lead to cell death regardless of the type of release process.

False

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

Induction

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

Transduction

_____ is when a phage transfers genes between bacteria.

Lysogenic, lytic

_____ phages enter the prophage state, while _____ phages burst the host cell.

Most

______ active viral infections lead to cell death. Only some No (none) Most

naked; enveloped

Capsids of ______ helical viruses are rigid and tight, while capsids of ______ helical viruses are flexible and loose. nonenveloped; naked enveloped; naked naked; nonenveloped naked; enveloped

protein

Capsomeres are composed of _______

proteins

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

capsomeres

This helical capsid is comprised of protein subunits called .

True

True or false: All viruses must infect a host cell in order to replicate.

True

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

True

True or false: Budding viruses do not lyse the host cell during release.

False

True or false: The viral envelope and capsid are the same thing.

True

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

True

True or false: Viruses are among the smallest infective agents.

True

True or false: Viruses can be both harmful or beneficial to humans.

True

True or false: Viruses can contain either DNA or RNA, but not both.

True

True or false: Viruses cannot be called organisms.

helical

Viruses which have a series of rod-shaped capsomer proteins linked together forming a series of interconnected hollow discs are termed ______. icosahedral diamond helical complex

dead; inactive

When referring to a microbe that cannot reproduce, the term ______ is to bacteria as the term ______ is to viruses. dead; inactive inactive; dead alive; dead

Nucleus

Where are most DNA viruses replicated and assembled within the host? Rough ER Cytoplasm Nucleus

Cytoplasm

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

Capsid

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

Viral specificity for host receptors

Which is most important for attachment of a virus to a host cell? Viral specificity for host receptors Viral shape and size Number of genes carried by the virus

Proteins

Which macromolecule composes capsomeres? Proteins Nucleic acids Carbohydrates Lipids

nucleocapsid

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

glycoprotein

The chemical composition of the viral structure indicated by the arrow is ______. nucleic acid glycoprotein lipid

Assemble

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

10

E. coli has about 4,000 genes in its chromosome. A virus that infects E. coli would be expected to have about ______ genes in its chromosome. 4,000 10 millions

integration of the viral genome into the host chromosome

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

self-limiting

Most human viral infections are ______. lethal chronic for life self-limiting

Nanometer

Most viruses are on the order of what size unit? Micrometer Picometer Nanometer Meter

cytopathic

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

Some viruses can be modified to deliver genetic cures via gene therapy Some viruses control insect pests Some viruses control food pathogens

Select all that apply Identify any benefits of viruses to people. Some viruses can lead to paralysis or death Some viruses can be modified to deliver genetic cures via gene therapy Some viruses control insect pests Some viruses control food pathogens

Viral positive-ssRNA --> proteins used by viruses Host DNA --> mRNA --> proteins used by viruses

Select all that apply Identify any of the following pathways which could produce proteins used by viruses. Viral positive-ssRNA --> proteins used by viruses Viral negative-ssRNA --> proteins used by viruses Host DNA --> mRNA --> proteins used by viruses

release

When it comes to virus multiplication, viral exocytosis refers to ______. absorption penetration uncoating release

Consumption of contaminated food

Which is the typical route of infection for mad cow disease? Consumption of contaminated food Insect-borne: tick Bite from an infected animal Insect-borne: mosquito

Proteinaceous infectious agent

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

Inclusion body

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

Syncytium

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

Prophage

Which of the following is used to describe the phage DNA that is latently incorporated into the bacterial host genome? Lysogenic Persistent infection Prophage Temperate Bacteriophage

Prion

Which of the following noncellular infectious agents is composed entirely of protein? Bacterium Virus Prion Viroid

uncoating

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

Creutzfeldt-Jakob disease

Which prion-associated spongiform encephalopathy is marked by dementia, impaired senses, and uncontrolled muscle contractions? Creutzfeldt-Jakob disease Poliomyelitis Hepatitis B virus

Transduction

Which process involves gene recombination via bacteriophage transfer? Conjugation Transposition Transduction

Lysogeny

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

Enveloped viruses

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

lysis

The term _____ is used to describe how some viruses burst cells during the release stage of viral multiplication.

virion

A single virus particle is known as a(n) ______

capsomere

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

enveloped

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

capsomere

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

reverse transcriptase

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

exocytic

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

Consume food Replicate outside of a cell

Identify which of the following statements represent activities that viruses CANNOT do. Infect cells Cause cancer Consume food Replicate inside of a cell Replicate outside of a cell

inactive

If the term "dead" is used to describe a particular bacterial cell then the term _____ would be used to describe a virus in a similar condition.

RNA

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

reverse transcriptase

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

nucleic acid

In this image of a naked virus, the red arrow is pointing to a ______. spike capsid nucleic acid

spike

In this image of a naked virus, the structure indicated by the arrow is the ______. capsid spike nucleic acid

spike

In this image of an enveloped virus, the red arrow is pointing to the _____. spike nucleic acid envelope capsid

envelope

In this image of an enveloped virus, the red arrow is pointing to the ______. capsid envelope nucleic acid spike

nucleic acid

In this image of an enveloped virus, the structure labeled with the arrow is the _____. capsid spike envelope nucleic acid

capsid

In this image of an enveloped virus, the structure labeled with the arrow is the _____. spike capsid nucleic acid envelope

Budding

In which way do enveloped viruses leave their host cell? Fusion Budding Lysis Endocytosis Rupture

Viruses cannot reproduce on their own. Viruses do not have any means of independent metabolism.

Select all that apply Which facts best support the position that viruses are not living organisms? Viruses are agents of disease. Viruses are small. Viruses cannot reproduce on their own. Viruses are not prokaryotic. Viruses do not have any means of independent metabolism.

Viruses cannot reproduce on their own. Viruses do not have any means of independent metabolism.

Select all that apply Which facts best support the position that viruses are not living organisms? Multiple select question. Viruses are small. Viruses cannot reproduce on their own. Viruses do not have any means of independent metabolism. Viruses are agents of disease. Viruses are not prokaryotic.

Endocytosis

The 2 principle processes by which viruses penetrate host cells are _____ (engulfment) and direct fusion.

glycoproteins

The membrane receptors that viruses attach to during adsorption are typically composed of ______. lipids phospholipids nucleic acid glycoproteins

uncoating

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.

much less than

The number of genes in a viral genome is _____ the number of genes in a bacterial genome. about the same as much less than much greater than

20 nanometers

The smallest animal virus, parvovirus, is approximately what size? 20 micrometers 0.2 millimeters 20 nanometers

capsid

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

capsomere

The structure represented here as the protein subunit of a helical capsid is termed a _____. spike icosahedron bacteriophage capsomere

naked

The virus indicated by the letter A is a _____ virus. crystalline naked living enveloped

enveloped

The virus indicated by the letter B is a(n) _____ virus. naked crystalline living enveloped

helical icosahedral

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

budding lysis

Two ways in which newly assembled viruses are released from host cells are through _____ (exocytosis) by enveloped viruses, and through _____ (rupture) by naked viruses.

less

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

Retroviruses

What are viruses called which are capable of converting their RNA genomes into DNA? RD viruses Autoviruses Reverse viruses (Rev-viruses) Retroviruses

Viruses must have a host cell

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

Spikes

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

individual genes are fragmented into small pieces of RNA.

When an RNA viral genome is described as segmented, this means that ______. individual genes are fragmented into small pieces of DNA. individual genes are repeated on different fragments of RNA. individual genes are fragmented into small pieces of RNA. individual genes are fragments into small pieces for later assembly.

significantly

When an enveloped virus buds off the cell membrane, the membrane differs ______ from the host cell's membrane. not at all modestly significantly

Parasitism

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

Obligate intracellular parasites

Which of the following best describes viruses? Obligate intracellular parasites Infectious proteins Living cells

Assembly

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

Host range

Which of the following is a term used to describe the different host cells which a virus can infect? Spread Host range Compatible range Virus range

Capsomere

Which of the following is the monomeric unit for a viral capsid? Amino acid Protein Facet Fiber Capsomere

Viruses insert their own proteins in the membrane.

Which of the following statements regarding the membrane on an enveloped virus is true? The membrane gives the virus particle a distinct shape. The membrane is identical to the host cell membrane. The viral envelope is not a lipid bilayer. Viruses insert their own proteins in the membrane.

Spike proteins

Which of the following structures of enveloped viruses must be specific for adsorption? Envelope Spike proteins Capsid Nucleic acid

Genome

Which of the following term describes the total nucleic content of a virus? Genome Chromosome Gene Capsid DNA mRNA

Budding

Which of the following viral release methods will not initially destroy the cell? Lysis Budding

Capsid

Which structure immediately encloses viral nucleic acid? Capsid Cell wall Envelope

Infectious particle

Which term describes a nonliving microscopic agent? Microbe Infectious particle Microorganism

Uncoating

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

Envelope

Which term is used to describe the phospholipid bilayer found surrounding the capsid of some viruses? Envelope Cell membrane Phagosome Vacuole

Endocytosis

Which term is used to describe the process when a virus is engulfed by a cell in a vacuole or vesicle? Budding Lysis Endocytosis Exocytosis

Adsorption

Which viral stage occurs first? Assembly Uncoating Adsorption Penetration Release Synthesis

Adsorption

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

Few

______ viruses in the human body are pathogenic. Few All No Most