Mastering Microbiology Chapter 13

Which is a complex virus?

(Diamond shape on spiral with legs → Spaceship looking)

Which of the following places these items in the correct order for DNA-virus replication

1-DNA synthesis 2-transcription 3-translation 4-maturation

In this stage of replication, the phage is put together in the host cell. The capsid heads are made from capsomeres, the tails assemble and attach to heads, the tail fibers attach to tails, and this creates a mature virion

Assembly

Bacteriophages and animal viruses do NOT differ significantly in which one of the following steps?

Attachment

In this stage of replication, the virion comes in contact with the bacterium and the tailfibers bind to the receptors on the surface on the bacterium cell wall

Attachment

Which statement concerning viral structure is true?

Spikes are found on some viruses. They are very consistent in structure within a viral species and can be used for identification.

In this stage of replication, the virus 19 enzymes cause the bacterium to synthesize viral molecules instead of its own molecules. The steps involved in this stage can very in complexity depending on what type of genetic material is housed in the viral capsid

Synthesis

Which one of the following steps does NOT occur during multiplication of a picornavirus?

Synthesis of DNA

The following steps occur during multiplication of retroviruses. Which is the fourth step?

Synthesis of double stranded DNA

another name for lysogenic phages that have a lysogenic replication cycle.

Temperate phages

Which of the following statements concerning viruses is true?

The "host range" for a virus is determined by the presence or absence of particular components on the surface of a host cell that are required for the virus to attach.

Which statement is INCORRECT concerning animal viruses?

The genome of animal viruses is always single-stranded.

How is the lytic cycle different from the lysogenic cycle with respect to the infected host cell?

The host cell dies during the lytic stage.

A lytic virus has infected a patient. Which of the following would best describe what is happening inside the patient?

The virus is causing the death of the infected cells in the patient.

Which of the following statements about viral spikes is FALSE?

They are found only on non-enveloped viruses.

Why do most scientists agree that viruses are nonliving entities?

They are not composed of cells.

What is NOT true regarding viruses that infect plants?

They are often cultured in embryonated chicken eggs.

Assume you have isolated an unknown virus. This virus has a single, positive sense strand of RNA, and possesses an envelope. To which group does it most likely belong?

Togavirus

Dogs do not get measles because their cells lack the correct receptor sites for that virus

True

Positive sense RNA strands of viruses are treated like mRNA inside the host cell.

True

The following steps occur during multiplication of herpesviruses. Which is the third step?

Uncoating

Which of the following is true of viroids?

Viroids are short pieces of naked RNA

How do all viruses differ from bacteria?

Viruses are not composed of cells

Which of the following statements best describes why antibiotics are ineffective treatments for the common cold?

Viruses do not possess targets for antibiotics

Which of the following statements about viruses is FALSE?

Viruses use their own catabolic enzymes.

Lysogenic viral DNA which has integrated into the host genome is referred to as

a Prophage

What contributes to antigenic shift in influenza viruses?

a segmented Genome

What is an oncogene?

an altered form of a gene that may induce cancer

The most conclusive evidence that viruses cause cancers was provided by

cancer that developed in chickens following injection of cell-free filtrates.

An example of a latent viral infection is

cold sores

Continuous cell lines differ from primary cell lines in that

continuous cell lines can be maintained through an indefinite number of generations.

Which virus is NOT associated with cancer?

coronavirus

Which of the following is NOT utilized to culture viruses?

culture media

All viruses can have both a capsid and an envelope

false

Capsids are acquired from the host cell during replication or release.

false

Helical and icosahedral are terms used to describe the shapes of a virus envelope.

false

The intracellular state of a virus is called a virion.

false

When the phenotype of a bacterium is changed via Lysogenic conversion

harmless bacteria can become pathogenic and are able to produce deadly toxins and proteins

What is the key characteristic of a transformed cell?

has acquired tumor-forming properties

A viral species is a group of viruses that

has the same genetic information and ecological niche.

Lysogeny can result in all of the following EXCEPT

immunity to reinfection by any phage.

a Prophage that can remain in the host chromosome and render the bacterium resistant to additional infection by other similar viruses.

inactive bacteriophage

A viroid is a(n)

infectious piece of RNA without a capsid

Some viruses, such as human herpesvirus 1, infect a cell without causing symptoms. These are called

latent virus

When a bacteriophage infects hosts 19 cells and allows them to grow and replicate normally for many generations before lysis, this is considered

lysogeny

The definition of lysogeny is

phage DNA is incorporated into host cell DNA.

A virus's ability to infect an animal cell depends primarily upon the

presence of receptor sites on the cell membrane.

Which of the following would be the first step in biosynthesis of a virus with a - (minus) strand of RNA?

synthesis of double-stranded RNA from an RNA template

A persistent infection is one in which

the disease process occurs gradually over a long period of time

A segmented genome can result in antigenic shift

true

Capsids function to surround and protect the nucleic acid core

true

Genomes of viruses are usually smaller than the genomes of bacteria

true

Most drugs that interfere with viral multiplication also interfere with host cell function.

true

The basic mechanism of viral multiplication is similar for all viruses

true

The genetic material of a virus can be DNA or RNA

true

Viruses are not capable of metabolic activity on their own, they must have a host cell to reproduce

true

Viruses can have different shapes

true

a phage is excised from the host chromosome via physical or chemical agents that damage the genetic material of the host

Induction

Bacteriophage replication differs from animal virus replication because only bacteriophage replication involves

Injection of naked nucleic acid into the host cell

Which of the following statements is NOT true of lysogeny?

It causes Lysis of the host cells

What is the fate of the prophage during the lysogenic stage?

It is copied every time the host DNA replicates.

Which of the following statements regarding latent viral infections is true?

Latent infections can persist for years in an individual without causing any symptoms.

Shingles is an example of

Latent virus being active

Bacteriophages derive all of the following from the host cell EXCEPT

Lysozyme

A feature that may be found in viruses but never in bacteria is

May contain RNA genome

Which of the following statements concerning prion diseases is true?

Normal host cellular prion proteins (PrPC) are converted into scrapie proteins (PrPSc).

The morphological types of viruses illustrated in the figure are ultimately determined by the

Nucleic Acid

________ were first identified in cancer-causing viruses and can induce ________ in infected cells.

Oncogenes and Transformation

A clear area against a confluent "lawn" of bacteria is called a

Plaque

Which of the following is necessary for replication of a prion?

PrP^Sc

An infectious protein is a

Prion

Which of the following types of macromolecules are found in all viruses

Proteins and Nucleic Acids

Most RNA viruses carry which of the following enzymes?

RNA dependent polymerase

An envelope is acquired during which of the following steps?

Release

In this stage of replication, the mature virions exit the cell and lysis occurs

Release

Which of the following are the main causative agents of the common cold?

Rhinoviruses and Coronaviruses

Arrange the following steps in the order in which they occur during the reproductive cycle of the type of virus that causes the common cold

Binding, Release of nucleic acid, Transcription, Capsid, Release of virus from cell

Which of the following is NOT used as a criterion to classify viruses?

Biochemical tests

The mechanism whereby an enveloped virus leaves a host cell is called

Budding

Oncogenic viruses

Cause tumors to develop

Which of the following is most likely a product of an early gene?

DNA Polymerase

Generally, in an infection caused by a DNA-containing virus, the host animal cell supplies all of the following EXCEPT

DNA polymerase

Which of the following is true regarding cultivation and isolation of animal viruses?

Diploid cell culture lines, developed from human embryos, are widely used for culturing viruses that require a human host.

Which of the following is true concerning a lysogenic viral replication cycle?

During lysogeny, the viral genome integrates into the host DNA, becoming a physical part of the chromosome.

In this stage of replication, the virion overcomes the cell wall barrier and cytoplasmic membrane and injects its genetic material into the bacterium cell.

Entry

Which of the following events might trigger induction of a temperate bacteriophage?

Exposure to UV light

A viroid is a completely developed infectious agent composed of nucleic acid and surrounded by a capsid.

False

Binomial nomenclature is used to name viruses.

False

Glycoprotein spikes are found on the capsids of all viruses

False

Viruses are the only known infectious agents that are obligatory intracellular parasites.

False

Each of the following can be used for the detection and/or identification of viruses except

Fermentation Tests -Fermentation tests are not useful for the identification of viruses since viruses don't ferment sugars or carry out other metabolic reactions.

Viruses that utilize reverse transcriptase belong to the virus families

Hepadnaviridae and Retroviridae.

DNA made from an RNA template will be incorporated into the virus capsid of

Hepadnaviridae.

An example of a persistent viral infection is

Human Immunodeficiency Virus infection.