Chapter 13 Exam

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 plaque. a dead zone. a burst area. a lyse area.

a plaque

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

acute infections.

Spongiform encephalopathy occurs in? humans. cattle. sheep. All of the choices are correct.

all the choices are correct

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

cytopathic effect.

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

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

When an enveloped virus adsorbs to the host cell with its protein spikes, the virions are taken into the cell by the process of? endocytosis. penetration. fusion. production.

endocytosis

The viral envelope closely resembles the -eukaryotic cell membrane. -prokaryotic cell wall. -capsomere. -cytoplasm.

eukaryotic cell

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

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

The receptors to which animal virus attachment proteins usually bind are? -proteins. -carbohydrates. -nucleic acid. -glycoproteins. -lipids.

glycoproteins

The receptors to which animal virus attachment proteins usually bind are? -proteins. -carbohydrates. -nucleic acid. -glycoproteins. -lipids.

glycoprotiens

The best-known examples of viruses that cause latent infections are? measles. herpes. herpes AND chickenpox. chickenpox. polio.

herpes AND chickenpox

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

identical DNA sequences in both.

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

lack of specific receptors on the host cell.

The phenomenon responsible for the ability of Corynebacterium diphtherium to produce the virulent toxin responsible for the devastating effects of diphtheria is called? lysogenic conversion. self-assembly. prion protein. matrix conversion.

lysogenic conversion.

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

lysogenic phages

A temperate phage -enters a lysogenic or lytic life cycle shortly after entering the host cell. -may be lytic. -may be lysogenic AND enters a lysogenic or lytic life cycle shortly after entering the host cell. -may be lysogenic. -are all RNA viruses.

may be lysogenic AND enters a lysogenic or lytic life cycle shortly after entering the host cell.

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

metabolically inert

What part of the E. coli T4 phage attaches to the host cell receptors? -Pili of the envelope. -Spikes of the envelope. -Capsid fragments around the nucleic acid. -Protein fibers at the end of the phage tail.

-Protein fibers at the end of the phage tail.

Lysogenized cells -respond to infection with the SOS response. -may have new properties. -are immune to infection by the same virus AND may have new properties. -are immune to infection by the same virus. -are immune to any further infection by any virus.

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

Transducing virulent phages do not lyse the cells they invade because? -bacterial DNA has replaced critical viral DNA in the phage. -transformation is taking place in the phage and this is transferred to the bacterium. -their virulence is dependent on the bacteria and virus replicating together. -the lytic genes are unable to enter during penetration and are shed outside the host.

-bacterial DNA has replaced critical viral DNA in the phage.

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

-functions necessary for cell survival are not carried out and the cell dies.

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

-have an outer lipid bilayer membrane containing various proteins.

Specialized transduction -involves the transfer of a few specific genes, utilizes a defective virus AND only involves genes near the viral DNA integration site. -utilizes a defective virus. -involves the transfer of a few specific genes. -involves the random transmission of any gene. -only involves genes near the viral DNA integration site.

-involves the transfer of a few specific genes, utilizes a defective virus AND only involves genes near the viral DNA integration site.

Assembly of the T4 phage -is completely self-assembly. -may involve the use of scaffolds. -is completely dependent on scaffolds. -may involve some self-assembly AND may involve the use of scaffolds. -may involve some self-assembly.

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

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

virulent or lytic phage.

In the case of T-even phages, the burst size is about? 5 per host cell. 200 per host cell. 1000 per host cell. 1 per host cell.

200 per host cell

Once inside the host cell, phage DNA? is replicated. is transcribed. may get degraded by bacterial nucleases. All of the choices are correct.

All of the choices are correct.

The nucleocapsid is composed of -protein located in the nucleus. -DNA or RNA and protein. -DNA and RNA and protein. -nucleic acid in the ribosome.

DNA or RNA and protein.

Which does not refer to the shape of a virus? helical bacillus complex icosahedral (isometric)

bacillus

Viruses that infect bacteria are referred to as -bacteriophages. -bacterialogens. -viralcidens. -bacteriocidins.

bacteriophages

In addition to lysis, animal viruses may exit the host cell by? fission. fusion. extrusion. budding.

budding

The shape of the virus is determined by its? envelope. nucleic acid. capsid. tail.

capsid

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

complete, extracellular virus particle.

In latent infections, the virions are -produced slowly. -continually being slowly budded out. -constantly produced. -only produced during reactivation.

only produced during reactivation.

An infection in which the virus is continually present in the body is referred to as? acute. determinant. persistent. balanced.

persistent.

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

presence of specific receptor molecules on the host cell.

Phage-encoded enzymes are -strictly host enzymes. -all produced simultaneously. -produced in a sequential manner. -produced in a sequential manner AND used to customize the cell for viral production. -used to customize the cell for viral production.

produced in a sequential manner AND used to customize the cell for viral production.

A virion is composed of? -protein and either RNA or DNA. -protein and both, RNA and DNA. -protein, either RNA or DNA, and possibly lipid. -lipid, protein, and either RNA or DNA.

protein, either RNA or DNA, and possibly lipid.

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

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

For which of the following processes are enzymes not required? maturation replication translation self-assembly

self assembly

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

separation of viral nucleic acid from the capsid.

In the region of budding, the plasma membrane becomes involved with? -carbohydrates. -matrix proteins. -spike proteins. -spike proteins AND matrix proteins. enzymes.

spike proteins AND matrix proteins. enzymes.

Attachment of animal viruses to the host cell may be by means of a tail. spikes. the envelope. a capsid.

spikes

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

spikes

RNA phages usually contain ssDNA. dsRNA. ssRNA. dsDNA.

ssRNA

What part of the attached bacteriophage enters through the host cell wall? -the entire virus -the nucleic acid and capsid -only the enzymes necessary for replication -the nucleic acid -the capsid only

the nucleic acid

During penetration of E. coli by the T4 phage -the protein fibers digest a hole in the cell wall. -the bacterial receptor molecules open a hole through the cell wall. -the tail acts as a "hypodermic needle", injecting the phage DNA into the cell. -lysozyme is used to allow entry of the phage capsid.

the tail acts as a "hypodermic needle", injecting the phage DNA into the cell.

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

true

The host range of a virus depends on the presence of host receptor molecules. True False

true

The integration of phage DNA into host DNA occurs in much the same fashion as seen in transformation, transduction or conjugation. True False

true

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

use RNA as a template to make DNA.

Animal viruses are divided into a number of families whose names end in -viscous. -viridae. -virus. -eieio.

viridae.

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

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

During attachment of phage to E. coli, the phage -actively seek out the bacteria. -attach to the bacterial RNA. -randomly bump into the bacteria. -randomly bump into the bacteria AND attach to proteins or carbohydrates on the bacterial surface. -attach to proteins or carbohydrates on the bacterial surface.

-randomly bump into the bacteria AND attach to proteins or carbohydrates on the bacterial surface.

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

All of the choices are correct.

Genetic exchange in segmented viruses that allows a zoonotic virus to infect humans is termed? antigenic drift. antigenic shift hemagglutination. genetic reassortment.

antigenic shift

Prions -are made of protein only. -are made of RNA only. -are made of dsRNA and protein. -consist of a special nucleocapsid.

are made of protein only.

The correct order for the stages of a phage infection is: -penetration, transcription, attachment, replication of nucleic acid and protein, assembly, release -attachment, penetration, transcription, replication of nucleic acid and protein, assembly, release -attachment, replication of nucleic acid and protein, penetration, transcription, assembly, release -transcription, attachment replication of nucleic acid and protein, assembly, penetration, release

attachment, penetration, transcription, replication of nucleic acid and protein, assembly, release

In the region of budding, the inside of the plasma membrane becomes coated with enzymes. steroids. matrix proteins. carbohydrates.

matrix protiens

DNA is protected from restriction enzymes by being? -methylated. -turned into RNA. -sequestered in a lysosome. -made into double stranded RNA.

methylated

Prions affect the -respiratory system. -gastrointestinal tract. -nervous system. -lymphatic system.

nervous system