Chapter 13- Viruses Test Questions

How is the HIV provirus different from a lambda-phage prophage? A) The HIV provirus is integrated permanently into the host cell's 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.

The HIV provirus is integrated permanently into the host cell's DNA.

Which of the following agents is capable of inducing conversion of a prophage to the lytic cycle? A) UV light B) X-rays C) presence of +ssRNA D) both UV light and X-rays E) both UV light and the presence of +ssRNA

both UV light and X-rays

The genome of which of the following types of animal virus can act directly as mRNA? A) dsDNA B) +ssRNA viruses C) -ssRNA viruses D) ssDNA viruses E) dsRNA viruses

+ssRNA viruses

RNA dependent RNA polymerase is required for successful infection by (+ssRNA/-ssRNA/dsRNA) viruses.

-ssRNA

Which of the following types 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

-ssRNA viruses

The virions shown in the figure have a (polyhedral/helical/complex) capsid. IIIIII IIIIII IIIIII IIIIII **** **** ****

Complex

Why are diploid cell cultures preferred over continuous cell cultures? A) Continuous cell cultures are expensive to maintain. B) Diploid cells last far longer than continuous culture cells. C) Diploid cells are more nearly like cells of whole organisms than continuous culture cells. D) Diploid cells have undergone changes in their chromosome structure that make them more stable. E) Results from continuous culture cells do not apply to disease in whole organisms.

Diploid cells are more nearly like cells of whole organisms than continuous culture cells.

Which virus is CORRECTLY matched with its method of entry? A) adenovirus; direct penetration B) herpesvirus; membrane fusion C) HIV; membrane fusion D) measles virus; direct penetration E) poliovirus; endocytosis

HIV; membrane fusion

What is the correct order for the stages of a lytic replication cycle, 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

III, V, I, II, IV

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 organism.

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

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 cell's DNA. E) It enables the bacteriophage to take over the cell.

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

What is one of the most difficult aspects of studying animal viruses? A) The viruses are hard to obtain. B) The study requires expensive facilities. C) The use of animals to study the viruses is unethical in the eyes of many. D) The viruses are extremely dangerous to handle. E) The use of animals is expensive, and unethical to many people.

The use of animals is expensive, and unethical to many people

How are fungal viruses different from viruses that infect other organisms? A) They have no extracellular state. B) They have only DNA for genetic material. C) They have no capsid. D) They have no intracellular state. E) They cannot pass through a filter.

They have no extracellular state.

) In contrast to most dsDNA animal viruses, the poxviruses replicate solely in the cytoplasm of the host cell. This fact implies that the viral genome may encode A) reverse transcriptase. B) a DNA polymerase. C) RNA-dependent RNA transcriptase. D) ribosome components. E) reverse transcriptase and RNA-dependent RNA transcriptase.

a DNA polymerase.

Virus replication results in the death of the cell in ________ infection(s). A) a lytic B) a latent C) a persistent D) a lysogenic E) both latent and persistent

a lytic

Which of the following is an accurate description of a Virion? A) the nucleic acid of a viral pathogen B) an infectious particle of protein and nucleic acid outside a host cell C) a population of infectious particles D) the protein portion of a viral particle E) the nucleic acid of a viral pathogen inside a host cell

an infectious particle of protein and nucleic acid outside a host cell

A__________ is a virus that infects bacterial cells. A) virion B) prion C) bacteriphage D) nucleopcapsid E) viroid

bacteriophage

The outermost layer of a Virion fulfills which of the following functions of the virus? A) protection B) recognition C) replication D) both protection and recognition E) both recognition and replication

both protection and recognition

The shape of a virion is a function of the ________ of the virus. A) size of the genome material B) cell type of the host cell C) type of genome material D) capsid E) envelope

capsid

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.

determining the density of phage in a culture

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

digestion of host DNA

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

entry and release

The first virus isolated, Tobacco mosaic virus, has a (complex/helical/polyhedral) capsid morphology, which facilitated its isolation.

helical

The envelope portion of an enveloped virus is composed of A) glycolipids of the host cell. B) virus-encoded glycoproteins. C) phospholipids from host cell membranes. D) host cell membranes containing virus-encoded glycoproteins. E) host glycolipids and virus-encoded glycoproteins.

host cell membranes containing virus-encoded glycoproteins.

) 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.

interactions between viral and cellular surface molecules.

During ________, viral synthesis is suspended. A) budding B) latency C) lytic replication D) persistent infection E) oncogenesis

latency

Zones of clearing in cell cultures that are the result of virus infection are called plaques. Sometimes "cloudy plaques" are seen on bacterial cultures infected with bacteriophage. What type of viral infection might cause this appearance? A) lytic B) lysogenic C) prion D) viroid E) transducing

lysogenic

The process of metastasis results from A) neoplasia. B) benign tumors. C) oncogene expression. D) malignant tumors. E) viral latency.

malignant tumors.

) Prions cause disease in A) mammals. B) plants. C) bacteria. D) fungi. E) birds.

mammals.

An animal virus that does not have an envelope is described as a(n) (naked/unenveloped/capsid) virion.

naked

Infection with ________ is likely to result in destruction of the host cell by lysis. A) enveloped viruses B) naked viruses C) oncogenic viruses D) viroids E) prions

naked viruses

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

neoplasia

Uncontrolled cell division in animals is known as (metastasis/neoplasia/cancer).

neoplasia

The combination of a virus's protein coat and nucleic acid core is called the (capsid/virion/nucleocapsid).

nucleocapsid

Three (orders/families/classes) represent the highest level of taxonomic rank used in classifying viruses.

orders

Classification of viruses includes A) classes. B) orders. C) families. D) orders and families. E) classes, orders, and families.

orders and families.

The graph in the figure shows a pattern of virion abundance consistent with a (lytic/latent/persistent) virus infection cycle.(SEE GRAPH)

persistent

A (colony/plaque) is a clear zone on a bacterial lawn where cells have been killed by the activity of a bacteriophage.

plaque

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

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

Genes that play a role in proper cell division but may also play a role in some types of cancer are called (oncogenes/protooncogenes/promoters).

protooncogenes

Which of the following is involved in the attachment of a bacteriophage to a bacterial cell? A) random collisions B) chemical attractions C) receptor specificity D) both chemical attractions and receptor specificity E) random collisions, chemical attractions, and receptor specificity

random collisions, chemical attractions, and receptor specificity

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 most likely to be involved in causing cancer by this mechanism? A) +ssRNA viruses B) dsRNA viruses C) -ssRNA viruses D) retroviruses E) both +ssRNA and -ssRNA viruses

retroviruses

Retroviruses require the activity of ________ to complete their infection cycle. A) lysozyme B) RNA-dependent RNA polymerase C) RNA-dependent RNA transcriptase D) reverse transcriptase E) viral RNA polymerase

reverse transcriptase

Viruses are responsible for (all/most/some) human cancers. (Use relative terms not numbers.)

some

4) Which of the following is present in cells only during virus infection? A) dsDNA B) ssRNA C) ssDNA D) DNA-RNA heteroduplex E) triplet RNA

ssDNA

Another term for a lysogenic phage is a (temperate/latent/prophage) phage.

temperate

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

the nuclear and cytoplasmic membranes, and the endoplasmic reticulum

Some human viruses are difficult to study because A) they grow very slowly. B) they establish latent infections and cannot be induced. C) the growth medium for the host cells is complex. D) they only grow in normal human cells. E) very few laboratories have the skills to culture the viruses.

they only grow in normal human cells.

A ________ is a mass of neoplastic cells. A) diploid culture B) metastasis C) tumor D) gall E) plaque

tumor

Small circular RNA molecules without capsids are characteristic of A) plasmids. B) viruses. C) viroids. D) prions. E) viruses and prions.

viroids.

The viruses of fungi have RNA genomes and lack a capsid. They are therefore similar to A) bacteriophages. B) enveloped viruses. C) prions. D) viroids. E) lysogens.

viroids.

1) Viruses cause most human cancers. 2) Virus entry requires the presence of specific cell structures. 3) Protozoa are susceptible to viral attack. 4) Many diseases of plants are caused by infectious RNA molecules lacking capsids. 5) All members of a virus family have the same type of genome structure. 6) Assembly of new viruses is a process that usually requires the direction of a variety of viral and cellular enzymes. 7) Bacteriophage release is a gradual process in which small numbers are released at a time. 8) Bovine spongiform encephalopathy is an example of a prion disease. 9) All viruses use the host cell's nucleic acid polymerases for replication. 10) Fertilized chicken eggs are used to culture some vaccine strains.

1) FALSE 2) TRUE 3) TRUE 4) TRUE 5) TRUE 6) FALSE 7) FALSE 8) TRUE 9) FALSE 10) TRUE

Which of the following may occur in a lysogenic infection, but NOT a latent one? A) The inserted viral DNA may leave the host DNA. B) The viral DNA integrates (inserts) into the host cell DNA. C) The provirus/prophage directs the synthesis of viral proteins. D) The prophage/provirus alters gene expression in the host cell. E) The prophage/provirus is replicated with the host DNA.

The inserted viral DNA may leave the host DNA

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.

They lack nucleic acid.

The development of a cancerous cell is said to require "multiple hits." This means A) the cell must be infected with several different types of viruses to be transformed. B) several protoncogenes are activated at the same time. C) multiple cell cycle regulators are inactivated at once. D) a series of separate events over time lead to the loss of cell cycle regulation. E) multiple oncogenic viruses infect the cell at the same time.

a series of separate events over time lead to the loss of cell cycle regulation.

The process known as ________ is a mechanism of release for enveloped viruses. A) lytic replication B) persistent infection C) metastasis D) latency E) budding

budding

The process in which viral capsids are removed within the infected cell is called (entry/disassembly/uncoating).

uncoating

Naked capsid animal viruses gain entry to host cells by A) endocytosis. B) direct penetration. C) membrane fusion. D) both endocytosis and direct penetration. E) endocytosis, direct penetration, and membrane fusion.

both endocytosis and direct penetration.

Diploid cell cultures and continuous cell cultures differ in which of the following ways? A) longevity B) source of cells C) convenience of use D) both longevity and convenience of use E) both longevity and source of cells

both longevity and source of cells