Chapter 13 Characterizing and Classifying Viruses, Viroids, & Prions Flashcards

In what ways do viruses differ from other pathogens?

a. viruses lack genetic makeup

b. viruses lack cytoplasm and organelles

c. viruses have no protein structure

d. viruses are composed of protein only

e. viruses are composed of both protein and lipid

The outermost layer of a virion fulills which of the following functions of the virus?

a. protection

b. recognition

c. replication

d. both protection and recognition

e. both recognition and replication

A(n) ___________ is a virus that infects bacterial cells

a. virion

b. prion

c. bacteriophage

d. nucleocapsid

e. envelope

Which of the following is a characteristic by which viruses are classified?

a. type of nucleic acid

b. type of life cycle

c. number of chromosomes

d. type of host

e. size

Host specificity of a virus is due to

a. particular genes that it shares with the infected cell

b. the presence of an envelope

c. differences in size between the virus and the host cell

d. the presence or absence of a cell wall on the host cell

e. interactions between viral and cellular surface molecules

Which of the following is primarily responsible for the shape of a virion?

a. the type of nucleic acid

b. the number of segments of the viral genome

c. the source of the envelope

d. the capsid

e. the specific host protein the virus targets

How are fungal viruses transmitted?

a. by insect vectors

b. as a result of abrasion

c. as a result of fusion of cells or hyphae

d. in the air like spores

e. by contact

The genome of influenza virus is

a. multiple pieces of linear dsDNA

b. a single circular ssRNA

c. a single linear dsRNA

d. a single circular ssDNA

e. multiple pieces of linear ssRNA

Which of the following is CORRECT regarding the viral envelope

a. it contains only viral proteins

b. it contains only host cell proteins

c. it is composed of sterols

d. it is composed of cellular phospholipid membrane, cellular and viral proteins

e. it is composed of sterols or viral proteins only

Which of the following statements regarding virus taxonomy is true?

a. viruses are classified on the basis of the taxonomy of their host organisms.

b. virus classes are well established

c. some virus family names are derived from the name of an important member of the family

d. the species epithet is a Latin descriptor of the virion structure

e. virus classes are based on the domain of the host organisma

Which of the following is NOT used for the classification of viruses?

a. genus

b. class

c. specific epithet

d. family

e. order

Which of the following lists stages of a lytic replication cycle in order, from earliest to latest stages?

I Synthesis

II Assembly

III Attachment

IV Release

V Entry

a. III,V,I,II,IV

b. III,II,V,I,IV

c. V, III, II, IV, I

d. I, III, V, II, IV

e. I,II,III,V,IV

Which of the following is associated with the attachment o a bacteriophage to a bacterial cell?

a. random collisions

b. chemical attractions

c. receptor specificity

d. both chemical attractions and receptor specifity

e. random collisions, chemical attractions, and receptor specificity.

The enzyme lysozyme is critical for which of the stages of a bacteriophage T4 infection cycle?

a. entry

b. assembly

c. entry and release

d. synthesis

e. attachment

A(n) ____________ is a bacterial virus which is integrated into the host cell DNA.

a. lytic phage

b. prophage

c. plasmid

d. transposon

e. insertion phage

Which of the following events occurs in the lytic cycle of bacteriophage T4 infection but NOT in the lysogenic cycle?

a. attachment

b. entry

c. digestion of host DNA

d. viral protein synthesis

e. both digestion of host DNA and viral proteins synthesis

Why is lysogeny advantageous to a bacteriophage?

a. it speeds up the viral infection cycle

b. the genetic material of the bacteriophage is amplified many times over that seen in a lytic phage.

c. it allows the bacteriophage to infect cells it would not normally infect

d. it allows the bacteriophage to destroy the host cells DNA

e. it enables the bacteriophage to take over the cell

Which of the following agents is capable of inducing conversion of a prophage to the lytic cycle?

a. UV light

b. Xrays

c. presence of ssRNA

d. both UV light and xrays

e. both UV light and the presence of ssRNA

Replication of most _____________ viruses is similar to normal cellular processes

a. dsDNA

b. ssDNA

c. +ssDNA

d. -ssDNA

e. dsRNA

Attachment of herpesviruses results in _______, a process in which the host cell facilitates viral entry.

a. direct penetration

b. membrane fusion

c. endocytosis

d. exocytosis

e. lysogeny

Reverse transcriptase is associated with which of the following?

a. dsDNA viruses

b. +ssRNA viruses

c. -ssRNA viruses

d. retroviruses

e. dsRNA viruses

The genome of which of the following types of animal virus can act directly as mRNA?

a. retroviruses

b. +ssRNA viruses

c. -ssRNA viruses

d. ssDNA viruses

e. dsRNA viruses

Which of the following type of animal virus requires RNA-dependent RNA transcriptase to be replicated

a. +ssRNA Viruses

b. ssDNA viruses

c. -ssRNA viruses

d. retroviruses

e. dsDNA viruses

Naked capsid animal viruses are commonly released from the infected cell by _____________, a process the host cell does not survive.

a. budding

b. lysis

c. endocytosis

d. membrane fusion

e. exocytosis

Which of the following membranes can give rise to a viral envelope?

a. the nuclear membrane

b. the cytoplasmic membrane

c. the endoplasmic reticulum

d. the nuclear and cytoplasmic membranes

e. the nuclear and cytoplasmic membranes and the endoplasmic reticulum

A cell is infected with a virus carrying an oncogene sequence in its genome. What process may occur if the oncogene is expressed in the infected cell?

a. lysis

b. neoplasia

c. lysogeny

d. latency

e. both lysis and neoplasia

How is the HIV provirus different from a lambda-phage prophage?

a. the HIV provirus is integrated permanently into the host cells DNA

b. all subsequent generations of HIV infected cells carry the provirus

c. all the offspring of a cell infected with a prophage will contain the virus

d. the HIV provirus is inactive inside the host cell

e. lambda phage infected cells produce virus slowly over time

Which of the following lab procedure is used for culturing animal viruses in the lab?

a. cell cultures

b. broth cultures

c. embryonated eggs

d. both cell cultures and embryonated eggs

e. synthetic cytoplasm

One mechanism by which viruses may cause cancer is to interrupt the genetic regulatory sequences of repressor proteins. Which of the following types of viruses is the most likely to be involved in cause cancer by this mechanism?

a. +ssRNA viruses

b. dsRNA viruses

c. -ssRNA viruses

d. retroviruses

e. both +ssRNA and -ssRNA viruses

Tumors invade other organs and tissues in a process called

a. neoplasia

b. uncoating

c. latency

d. budding

e. metastasis

Plaque assays are used for

a. evaluating the cancer-causing ability of a virus

b. determining the density of phage in a culture

c. the study of prions

d. cultivating viruses that cannot be grown any other way

e. counting the number of latent phages in a cell

Disadvantages of continuous cell cultures include

a. they only grow for a limited number of generations

b. the expense of preparation

c. they may be significantly different genetically from the original source animal

d. viruses do not reliably infect them

e. they are both expensive and have a limited numer of division

Viroids infect

a. bacteria

b. plants

c. fungi

d. plants and animals

e. all organisms

How are prions different from all other known infectious agents?

a. they cannot reproduce outside a cell

b. they act as slow viruses

c. they cause neurological problems

d. they can be destroyed by incineration

e. they lack nucleic acid

which of the following infectious particles do NOT have protein in their structure?

a. bacteriophages

b. prions

c. animal viruses

d. viroids

e. both prions and viroids

A lipid membrane is present in which of the following?

a. naked viruses

b. enveloped viruses

c. prions

d. viroids

e. both prions and viroids

What is a virion?

a. a virus genome inside a cell

b. an empty capsid

c. a single virus particle outside a cell

d. an extracellular virus genome

e. a virus genome integrated into a host cell genome

Which of the following virus families has a double stranded RNA genome?

a. Retroviridae

b. Reoviridae

c. Rhadoviridae

d. Orthomyxoviridae

e. Filoviridae

Which of the following is a feature shared by viruses and living organisms?

a. possession of a genome that directs synthesis of materials necessary for replication

b. presence of cytoplasm

c. metabolic capability

d. responsiveness

e. the ability to increase in size

Small circular RNAs called ________ are plant pathogens

a. plasmids

b. viruses

c. viroids

d. prions

e. phages

The __________ of a virion determines the type of cell it enters

a. nucleic acid

b. matrix proteins

c. glycoproteins

d. lipid molecules

e. shape

Which of the following infectious particles is most susceptible to damage

a. naked capsid virus

b. enveloped virus

c. prions

d. bacteriophage

e. both naked capsid viruses and prions

A viral infection which does not result in the production of new virions is _____ infection(s)

a. lytic

b. a latent

c. a persistent

d. a lysogenic

e. either latent or lysogenic

A _______ is a mass of neoplastic cells.

a. diploid culture

b. metastasis

c. tumor

d. gall

e. plaque

The process known as ________________ is a mechanism of release for enveloped viruses

a. lytic replication

b. persistent infection

c. metastasis

d. latency

e. budding

True/False

Viruses cause most human cancers

True/False

Most viruses cannot be seen by light microscopy

True/False

Protozoa are susceptible to viral attack

True/False

Budding release of virus may result in long lasting or persistent infection

True/False

Members of a virus family have the same type of nucleic acid

True/False

The genome of all DNA animal viruses is replicated in the nucleus of the cell

True/False

Bacteriophage release is a gradual process in which small numbers are released at a time

True/False

Bovine spongiform encephalopathy is an example of a prion disease

True/False

All viruses use the host cells nucleic acid polymerases for replication

True/False

Fertilized chicken eggs are used to culture some vaccine strains