Micro Quiz 4

The structure of plant, animal and bacterial viruses are each, fundamentally, very different from one another. True False

False

The restriction-modification system always has two genes involved, the cutting enzyme and the methylating enzyme. True False

True

Viruses that cause acute infection result in productive infections. True False

True

The bacterial viruses that are released by a process termed extrusion are called a. lysogenic viruses. b. temperate phages. c. filamentous phages. d. Lambda viruses.

c. filamentous phages.

RNA phages usually contain a. dsRNA. b. dsDNA. c. ssRNA. d. ssDNA.

c. ssRNA

What part of the attached bacteriophage enters through the host cell wall? a. The entire virus b. Only the enzymes necessary for replication c. The nucleic acid d. The nucleic acid and capsid e. The capsid only

c. the nucleic acid

Retroviruses are unique in that they a. replicate in nervous system cells. b. do not have a capsid. c. use RNA as a template to make DNA. d. use DNA as a template to make RNA

use RNA as a template to make DNA.

A lysogenic cell contains viral DNA, a prophage, integrated into the host chromosome. A. True B. False

A. True

The integration of phage DNA into the bacterial chromosome occurs because of A. identical DNA sequences in both. B. the phage's ability to synthesize enzymes to enter the bacterium. C. similar RNA nucleotides in both. D. the similarity in enzyme metabolism. E. the phage's ability to synthesize enzymes to enter the bacterium AND similar RNA nucleotides in both.

A. identical DNA sequences in both.

Phages that can either replicate and cause cell lysis or can integrate their DNA into the host DNA are called A. lysogenic phages. B. lytic phages. C. virulent phages. D. segmented phages.

A. lysogenic phages

The filamentous phages all contain A. single-stranded DNA. B. double-stranded DNA. C. single-stranded RNA. D. double-stranded RNA.

A. single-stranded DNA

A phage that replicates inside the host cell and then lyses its host during its release is a A. virulent or lytic phage. B. latent phage. C. lysogenic phage. D. dormant phage.

A. virulent or lytic phage

The nucleocapsid is composed of A. DNA, RNA, and protein. B. DNA or RNA and protein. C. protein located in the nucleus. D. nucleic acid in the ribosome.

B. DNA or RNA and protein

Bacteriophage, unlike animal viruses, often have special viral-specific enzymes carried in the capsid which enter the host cell at the same time as the nucleic acid. A. True B. False

B. False

In addition to lysis, animal viruses may exit the host cell by A. extrusion. B. budding. C. fission. D. fusion.

B. budding

The groups of organisms that a virus may infect is known as its A. target circle. B. host range. C. susceptible group. D. receptor type.

B. host range

In latent infections, the virions are A. constantly produced. B. only produced during reactivation. C. produced slowly. D. continually being slowly budded out.

B. only produced during reactivation

Diseases of short duration frequently followed by long-term immunity are referred to as A. intermittent infections. B. chronic infections. C. acute infections. D. persistent infections.

C. acute infections

A virion is a(n) A. pathogenic virus. B. subviral particle. C. complete, extracellular virus particle. D. enveloped virus particle.

C. complete, extracellular virus particle

The viral envelope closely resembles the A. prokaryotic cell wall. B. capsomere. C. eukaryotic cell membrane. D. cytoplasm.

C. eukaryotic cell membrane

Cells infected with animal viruses lyse because A. the release of the virions depletes the cell of energy. B. the virus releases enzymes that lyse the cell. C. functions necessary for cell survival are not carried out and the cell dies. D. the virus RNA and cellular protein interact to kill the cell.

C. function necessary for cell survival are not carried out and the cell dies

DNA is protected from restriction enzymes by being A. sequestered in a lysosome. B. turned into RNA. C. methylated. D. made into double stranded RNA.

C. methylated

Which does not refer to the shape of a virus? A. Icosahedral (isometric) B. Helical C. Complex D. Bacillus

D. Bacillus

If reasonably pure preparations of virus are available, the number of virus present may be determined by A. photocolorimetry. B. gas chromatography. C. light microscopy. D. electron microscopy.

D. electron microscopy

Resistance of some animals to certain viral diseases is based on A. lack of spikes for attachment. B. phagocytosis of the virus by the host cell. C. the presence of the viral envelope. D. lack of specific receptors on the host cell.

D. lack of specific receptors on the host cell

A key feature of all viral infections is the A. integration of viral DNA into host DNA. B. disintegration of host DNA. C. addition of a lipid membrane to the virus. D. separation of viral nucleic acid from the capsid.

D. separation of viral nucleic acid form the capsid.

A limiting factor for viral infection is A. internal metabolic temperature of the host cell. B. nutrition of the host cell. C. stage of cell cycle of the host cell. D. presence of specific receptor molecules on the host cell

D. the presence of specific receptor molecules on the host cell

Assembly of the T4 phage a. may involve some self assembly. b.may involve the use of scaffolds. c. is completely self assembly. d. is completely dependent on scaffolds. e. may involve some self assembly AND may involve the use of scaffolds.

E. may involve some self assembly AND may involve some self assembly AND may involve the use of scaffolds

The terms isometric, icosahedral and pleomorphic refer to A. viral life cycles. B. forms of nucleic acid. D. types of viral envelopes. E. shapes of viruses.

E. shapes of viruses

Capsids are made of a number of capsomeres, which are covalently bonded to one another. True False

False

The changes that occur in virally-infected cells are characteristic for a particular virus and are referred to as the a. cytopathic effect. b. phenotypic effect. c. genotypic expression. d. cytology.

a. cytopathic effect.

The family to which the Rhinovirus belongs is the a. Picornaviridae. b. Enterovirus. c. Enteroviridae. d. Picornavirus.

a. Picornaviridae.

All viruses must separate the nucleic acid from the capsid before replication. a. True b. False

a. True

The term segmented refers to viruses that a. may contain several pieces of RNA. b. have an icosahedral-shaped capsid. c. are linked together before budding out. d. have an envelope.

a. may contain several pieces of RNA.

After growth in tissue culture, the infected cells lyse and the virus may be harvested from a. the liquid supernatant after centrifugation, the lysate. b. the remainder. c. the quantal layer. d. the monolayer.

a. the liquid supernatant after centrifugation, the lysate.

A phage that replicates inside the host cell and then lyses its host during its release is a a. virulent or lytic phage. b. latent phage. c. lysogenic phage. d. dormant phage.

a. virulent or lytic phage.

The correct order for the stages of a phage infection are: a. Penetration, transcription, attachment, replication of nucleic acid and protein, assembly, release b. Attachment, penetration, transcription, replication of nucleic acid and protein, assembly, release c. Attachment, replication of nucleic acid and protein penetration, transcription, assembly, release d. Transcription, attachment replication of nucleic acid and protein, assembly, penetration, release

b. Attachment, penetration, transcription, replication of nucleic acid and protein, assembly, release

The nucleocapsid is composed of a. DNA, RNA, and protein. b. DNA or RNA and protein. c. protein located in the nucleus. d. nucleic acid in the ribosome.

b. DNA or RNA and protein.

One of the most intensively studied virulent phages which infects E. coli is a. T9. b. T4. c. beta. d. gamma.

b. T4.

The shape of the virus is determined by its a. nucleic acid. b. capsid. c. envelope. d. tail.

b. capsid.

Enveloped viruses a. just require a stamp. b. have an outer lipid bilayer membrane containing various proteins. c. are surrounded by an additional layer of carbohydrate. d. envelope a cell.

b. have an outer lipid bilayer membrane containing various proteins.

The site at which a virus has infected and subsequently lysed the infected cell, releasing its progeny to infect and lyse surrounding cells, thereby forming a "clear zone", is referred to as a. a burst area. b. a lyse area. c. a plaque. d. a dead zone.

c. a plaque

The viral envelope closely resembles the a. prokaryotic cell wall. b. capsomere. c. eukaryotic cell membrane. d. cytoplasm.

c. eukaryotic cell membrane.

An exit method used by viruses which does not immediately destroy the host bacterium is a. lysis. b. inversion c. extrusion d. excising.

c. extrusion

Regarding phage replication, a. the majority of phages are temperate. b. when integrated into host DNA, the phage DNA is called a prophage. c. lambda is a good example of a temperate phage. d. All of the choices are correct.

d. All of the choices are correct.

Spongiform encephalopathy occurs in a. humans. b. cattle. c. sheep. d. All of the choices are correct.

d. all of the choices are correct

Viruses that infect bacteria are referred to as a. viralcidens. b. bacteriocidins. c. bacterialogens. d. bacteriophages.

d. bacteriophages

The condition in which the virus infects and persists within the host with no obvious harm is a. disease. b. colonization. c. adaptation. d. balanced pathogenicity.

d. balanced pathogenicity

Bacteriophages and animal viruses a. both may enter a host cell by endocytosis. b. both may enter a host cell by fusion. c. both involve entry of the entire nucleocapsid. d. differ because bacteriophages leave the capsid outside the cell, while animal virus entry involves the entry of the whole nucleocapsid.

d. differ because bacteriophages leave the capsid outside the cell, white animal virus entry involves the entry of the whole nucleocapsid.

If reasonably pure preparations of virus are available, the number of virus present may be determined by a. photocolorimetry. b. gas chromatography. c. light microscopy. d. electron microscopy.

d. electron microscopy.

Outside of living cells, viruses are a. scavenging glucose. b. slowly stockpiling ATP from the mitochondria. c. using cilia to move to the next host. d. metabolically inert.

d. metabolically inert.

An infection in which the virus is continually present in the body is referred to as a. acute. b. balanced. c. determinant. d. persistent.

d. persistent

The protein projections on the surface of a virus that are involved in attachment to the host cell are called a. suckers. b. pili. c. cilia. d. spikes. e. hooks.

d. spikes.

Prions a. replicate by converting normal host proteins into prion proteins. b. responsible for "Mad Cow Disease" can cause a similar disease in humans. c. can be transmitted by consumption of dried or cooked prions. d. that cause spongiform encephalopathy have the same amino acids but different folding properties from PrPc. e. All of the above

e. all of the above

Lysogenic cells a. are immune to any further infection by any virus. b. are immune to infection by the same virus. c. may have new properties. d. respond to infection with the SOS response. e. are immune to infection by the same virus AND may have new properties.

e. are immune to infection by the same virus AND may have new properties.

Viruses are commonly referred to by their _________ name. a. locale b. genus c. disease d. species e. disease AND species

e. disease AND species

The enveloped viruses typically obtain their envelope a. from the host plasma membrane. b. as they exit the host. c. from a newly constructed viral-derived membrane. d. from the nuclear membrane. e. from the host plasma membrane AND as they exit the host.

e. from the host plasma membrane AND as they exit the host.

The receptors to which animal virus attachment proteins usually bind are a. proteins. b. carbohydrates. c. nucleic acid. d. lipids. e. glycoproteins.

e. glycoproteins.

The protein coat of a virus a. is called a capsomere. b. is called a capsid. c. protects the nucleic acid. d. is involved in recognition of host cell receptors. e. is called a capsid, protects the nucleic acid, AND is involved in recognition of host cell receptors.

e. is called a capsid, protects the nucleic acid, AND is involved in recognition of host cell receptors.

Carriers a. may have a persistent infection. b. may be a source of infection. c. usually show symptoms of the disease. d. have been cured of the infection. e. may have a persistent infection AND may be a source of infection.

e. may have a persistent infection AND may be a source of infection.

Viruses a. probably keep the numbers of bacteria in check. b. have no effect on the number of bacteria. c. increase the number of bacteria. d. are active in passing DNA from one bacterium to another. e. probably keep the numbers of bacteria in check AND are active in passing DNA from one bacterium to another.

e. probably keep the numbers of bacteria in check AND are active in passing DNA from one bacterium to another.