Question 1

Which is a filamentous phage?

Accepted Answer

A)  M13 
B)  T4 
C)  Lambda 
D)  TMV 
E)  T2 
A)  M13 
B)  T4 
C)  Lambda 
D)  TMV 
E)  T2

Question 2

Why do animal viruses have envelopes and phages rarely do?

Accepted Answer

A)  Since bacteria don't have cell membranes, the bacterial viruses (phages) don't pick them up when they leave the target cells. 
B)  Phages acquire an outer surrounding that is a part of the cell wall of the bacterium they were created in, rather than an outer surrounding of plasma membrane. 
C)  Animal viruses will often use the envelope in order to fuse with the plasma membrane of a new target cell, gaining entry into the cytoplasm. 
D)  Animal viruses build the envelope inside of the target cell as they are being replicated, but before the cell breaks open and releases them into the extracellular environment. The envelope is a remnant of this building process. 
E)  This is a trick question. Plenty of bacteriophages have envelopes that they acquire when they bud through the lipopolysaccharide layer of the bacterial host. 
A)  Since bacteria don't have cell membranes, the bacterial viruses (phages) don't pick them up when they leave the target cells. 
B)  Phages acquire an outer surrounding that is a part of the cell wall of the bacterium they were created in, rather than an outer surrounding of plasma membrane. 
C)  Animal viruses will often use the envelope in order to fuse with the plasma membrane of a new target cell, gaining entry into the cytoplasm. 
D)  Animal viruses build the envelope inside of the target cell as they are being replicated, but before the cell breaks open and releases them into the extracellular environment. The envelope is a remnant of this building process. 
E)  This is a trick question. Plenty of bacteriophages have envelopes that they acquire when they bud through the lipopolysaccharide layer of the bacterial host.

Question 3

If a virus utilizes a lytic life cycle of reproduction, it will not induce tumors.

Accepted Answer

A) True 
 B)False

Question 4

The phenomenon responsible for the ability of Corynebacterium diphtherium to produce the virulent toxin responsible for the devastating effects of diphtheria is called

Accepted Answer

A)  self-assembly. 
B)  matrix conversion. 
C)  lysogenic conversion. 
D)  prion protein. 
E)  phase variation. 
A)  self-assembly. 
B)  matrix conversion. 
C)  lysogenic conversion. 
D)  prion protein. 
E)  phase variation.

Question 5

A temperate phage

Accepted Answer

A)  may be lysogenic. 
B)  may be lytic. 
C)  enters a lysogenic or lytic life cycle shortly after entering the host cell. 
D)  may be lytic AND enters a lysogenic or lytic life cycle shortly after entering the host cell. 
E)  may be lysogenic AND enters a lysogenic or lytic life cycle shortly after entering the host cell. 
A)  may be lysogenic. 
B)  may be lytic. 
C)  enters a lysogenic or lytic life cycle shortly after entering the host cell. 
D)  may be lytic AND enters a lysogenic or lytic life cycle shortly after entering the host cell. 
E)  may be lysogenic AND enters a lysogenic or lytic life cycle shortly after entering the host cell.

Question 6

Which statement about most phages that contain single-stranded DNA is NOT true?

Accepted Answer

A)  They are extruded from the host cell. 
B)  They contain a negative-sense DNA strand. 
C)  Their DNA is transformed to dsDNA before replication and transcription occur. 
D)  All of the choices are correct. 
E)  None of the choices is correct. 
A)  They are extruded from the host cell. 
B)  They contain a negative-sense DNA strand. 
C)  Their DNA is transformed to dsDNA before replication and transcription occur. 
D)  All of the choices are correct. 
E)  None of the choices is correct.

Question 7

Most temperate phages integrate into the host chromosome, whereas some replicate as plasmids. Which kind of relationship do you think would be more likely to maintain the phage in the host cell, and why?

Accepted Answer

A)  Plasmids; they're smaller, so they would be easier to replicate by the host cell. 
B)  Integrated; the host cell would be less likely to view this DNA as "foreign" on subsequent rounds of replication, and would retain it more easily. 
C)  Plasmids; these structures often carry other genes that may give the host cell a selective advantage over cells that don't have them. 
D)  Integration, because plasmids are frequently lost during cell division, which could leave a daughter cell without the virus genome. 
E)  Either plasmids or integration because once a virus genome is in a host cell, there is not way for that genome to be removed from the infected cell. 
A)  Plasmids; they're smaller, so they would be easier to replicate by the host cell. 
B)  Integrated; the host cell would be less likely to view this DNA as "foreign" on subsequent rounds of replication, and would retain it more easily. 
C)  Plasmids; these structures often carry other genes that may give the host cell a selective advantage over cells that don't have them. 
D)  Integration, because plasmids are frequently lost during cell division, which could leave a daughter cell without the virus genome. 
E)  Either plasmids or integration because once a virus genome is in a host cell, there is not way for that genome to be removed from the infected cell.

Question 8

Outside of living cells, viruses are

Accepted Answer

A)  scavenging glucose. 
B)  gaining ATP from the mitochondria. 
C)  metabolically inert. 
D)  using cilia to move to the next host. 
E)  replicating by binary fission. 
A)  scavenging glucose. 
B)  gaining ATP from the mitochondria. 
C)  metabolically inert. 
D)  using cilia to move to the next host. 
E)  replicating by binary fission.

Question 9

Diseases of short duration frequently followed by long-term immunity are referred to as

Accepted Answer

A)  intermittent infections. 
B)  chronic infections. 
C)  acute infections. 
D)  persistent infections. 
E)  nonacute infections. 
A)  intermittent infections. 
B)  chronic infections. 
C)  acute infections. 
D)  persistent infections. 
E)  nonacute infections.

Question 10

Once integrated, phage DNA can remain in the prophage state as long as

Accepted Answer

A)  the bacteria is frequently plated on new media. 
B)  certain phage genes are excised. 
C)  certain phage genes are repressed. 
D)  bacterial repressor genes are activated. 
E)  bacterial repressor genes are deactivated. 
A)  the bacteria is frequently plated on new media. 
B)  certain phage genes are excised. 
C)  certain phage genes are repressed. 
D)  bacterial repressor genes are activated. 
E)  bacterial repressor genes are deactivated.

Question 11

The bacterial viruses that are released by a process termed extrusion are called

Accepted Answer

A)  lysogenic viruses. 
B)  temperate phages. 
C)  filamentous phages. 
D)  lambda viruses. 
E)  helical phages. 
A)  lysogenic viruses. 
B)  temperate phages. 
C)  filamentous phages. 
D)  lambda viruses. 
E)  helical phages.

Question 12

In order to treat cholera, antiviral medication must be given to get rid of the bacteriophage that carries the cholera toxin gene.

Accepted Answer

A) True 
 B)False

Question 13

In the region of budding, the cytoplasmic membrane acquires

Accepted Answer

A)  carbohydrates AND spike proteins. 
B)  spike proteins AND enzymes. 
C)  spike proteins AND matrix proteins. 
D)  matrix proteins AND carbohydrates. 
E)  enzymes AND matrix proteins. 
A)  carbohydrates AND spike proteins. 
B)  spike proteins AND enzymes. 
C)  spike proteins AND matrix proteins. 
D)  matrix proteins AND carbohydrates. 
E)  enzymes AND matrix proteins.

Question 14

Infective and non-infective viruses may be distinguished by growth on MacConkey's agar.

Accepted Answer

A) True 
 B)False

Question 15

Please select the TRUE statement regarding bacteriophage life cycles.

Accepted Answer

A)  Temperate phages lyse their host cells, whereas lytic phages either lyse their host or integrate their DNA into the host cell's genome. 
B)  Lytic phages lyse their host cells, whereas temperate phages either lyse their host or integrate their DNA into the host cell's genome. 
C)  In the bacteriophage life cycle, the entire virus enters the host bacterial cell through a hole in the cell wall. 
D)  Phage particles seek out their bacterial hosts by means of chemotaxis and then attach to random receptors on the host's cell wall. 
E)  The burst size is the number of bacterial cells that are lysed as a result of being infected by a bacteriophage such as T4. 
A)  Temperate phages lyse their host cells, whereas lytic phages either lyse their host or integrate their DNA into the host cell's genome. 
B)  Lytic phages lyse their host cells, whereas temperate phages either lyse their host or integrate their DNA into the host cell's genome. 
C)  In the bacteriophage life cycle, the entire virus enters the host bacterial cell through a hole in the cell wall. 
D)  Phage particles seek out their bacterial hosts by means of chemotaxis and then attach to random receptors on the host's cell wall. 
E)  The burst size is the number of bacterial cells that are lysed as a result of being infected by a bacteriophage such as T4.

Question 16

What is a defective phage?

Accepted Answer

A)  A virus that has lost some of its genetic material, and therefore cannot infect a new target cell. 
B)  A virus that has lost some of its genetic material, and therefore cannot replicate within a new target cell. 
C)  A virus that lacks the ability to replicate independently of its host cell and cannot survive. 
D)  A virus that cannot attach to its host cell and therefore cannot enter the target cell. 
E)  A virus that lacks a prophage, cannot enter a host cell, and cannot survive. 
A)  A virus that has lost some of its genetic material, and therefore cannot infect a new target cell. 
B)  A virus that has lost some of its genetic material, and therefore cannot replicate within a new target cell. 
C)  A virus that lacks the ability to replicate independently of its host cell and cannot survive. 
D)  A virus that cannot attach to its host cell and therefore cannot enter the target cell. 
E)  A virus that lacks a prophage, cannot enter a host cell, and cannot survive.

Question 17

Most enveloped viruses, like hepatitis B, are released by budding, a process whereby the virus acquires its envelope. Before budding occurs, virally encoded protein spikes insert into specific regions of the host cell's membrane. Given this information, which of the following would you tell your friend best describes the structure of the viral envelope?

Accepted Answer

A)  Phospholipid bilayer 
B)  Phospholipid bilayer with host-derived proteins. 
C)  Phospholipid bilayer studded with both virus- and host-derived proteins. 
D)  Protein layer with host-derived spikes. 
E)  Phospholipid monolayer studded with virus- and host-derived proteins. 
A)  Phospholipid bilayer 
B)  Phospholipid bilayer with host-derived proteins. 
C)  Phospholipid bilayer studded with both virus- and host-derived proteins. 
D)  Protein layer with host-derived spikes. 
E)  Phospholipid monolayer studded with virus- and host-derived proteins.

Question 18

Which does not refer to the shape of a virus?

Accepted Answer

A)  Bacillus 
B)  Icosahedral 
C)  Helical 
D)  Complex 
E)  These are all virus shapes. 
A)  Bacillus 
B)  Icosahedral 
C)  Helical 
D)  Complex 
E)  These are all virus shapes.

Question 19

Viruses that cause acute infection result in productive infections.

Accepted Answer

A) True 
 B)False

Question 20

You add an unknown phage to a mixture of F+ and F− cells of E. coli and plate out the bacteria. The bacterial colonies that grow are all F−. How can you explain this phenomenon?

Accepted Answer

A)  The phage bound to a receptor on the sex pilus, and therefore only infected the F+ cells (leaving the F− cells alone). 
B)  The phage bound to a receptor on the F− cells, leaving only them alive and allowing the F+ cells to die off. 
C)  The phage integrated (lysogenized) the F− cells, giving them a selective advantage over the F+ cells. 
D)  F+ cells are uniquely susceptible to phage attack for unknown reasons. 
E)  F+ are well known to die in the presence of any type of bacteriophage. 
A)  The phage bound to a receptor on the sex pilus, and therefore only infected the F+ cells (leaving the F− cells alone). 
B)  The phage bound to a receptor on the F− cells, leaving only them alive and allowing the F+ cells to die off. 
C)  The phage integrated (lysogenized) the F− cells, giving them a selective advantage over the F+ cells. 
D)  F+ cells are uniquely susceptible to phage attack for unknown reasons. 
E)  F+ are well known to die in the presence of any type of bacteriophage.

Exam 13: Viruses, Viroids, and Prions

Which is a filamentous phage?

Why do animal viruses have envelopes and phages rarely do?

If a virus utilizes a lytic life cycle of reproduction, it will not induce tumors.

The phenomenon responsible for the ability of Corynebacterium diphtherium to produce the virulent toxin responsible for the devastating effects of diphtheria is called

A temperate phage

Which statement about most phages that contain single-stranded DNA is NOT true?

Most temperate phages integrate into the host chromosome, whereas some replicate as plasmids. Which kind of relationship do you think would be more likely to maintain the phage in the host cell, and why?

Outside of living cells, viruses are

Diseases of short duration frequently followed by long-term immunity are referred to as

Once integrated, phage DNA can remain in the prophage state as long as

The bacterial viruses that are released by a process termed extrusion are called

In order to treat cholera, antiviral medication must be given to get rid of the bacteriophage that carries the cholera toxin gene.

In the region of budding, the cytoplasmic membrane acquires

Infective and non-infective viruses may be distinguished by growth on MacConkey's agar.

Please select the TRUE statement regarding bacteriophage life cycles.

What is a defective phage?

Which does not refer to the shape of a virus?

Viruses that cause acute infection result in productive infections.

You add an unknown phage to a mixture of F+ and F− cells of E. coli and plate out the bacteria. The bacterial colonies that grow are all F−. How can you explain this phenomenon?

Humans and the Microbial World

The Molecules of Life

Microscopy and Cell Structure

Dynamics of Microbial Growth

Control of Microbial Growth

Microbial Metabolism: Fueling Cell Growth

The Blueprint of Life, From Dna to Protein

Bacterial Genetics

Biotechnology

Identifying and Classifying Microorganisms

The Diversity of Bacteria and Archaea

The Eukaryotic Members of the Microbial World

The Innate Immune Response

The Adaptive Immune Response

Host-Microbe Interactions

Immunological Disorders

Applications of Immune Responses

Epidemiology

Antimicrobial Medications

Respiratory System Infections

Skin Infections

Wound Infections

Digestive System Infections

Blood and Lymphatic Infections

Nervous System Infections

Genitourinary Tract Infections

Microbial Ecology

Environmental Microbiology: Treatment of Water, Wastes, and Polluted Habitats

Food Microbiology

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