Deck 24: Viruses and Subviral Agents

Question 1

Which of the following typically occurs all at once and results in rapid cell lysis?

A) Penetration
B) Replication and synthesis
C) Phage release
D) Viral components
E) Viral contrast

Answer 1

C

Question 2

What is the purpose of phage therapy?

A) To supplement gene therapy
B) To build antibiotic resistance
C) To target and destroy cancer cells
D) To improve replication of other viruses
E) To target specific bacteria in the body and destroy them

Answer 2

E

Question 3

Which statement describes a virulent phage?

A) A virulent phage infects viruses.
B) A virulent phage infects prions.
C) A virulent phage infects virions.
D) A virulent phage destroys bacteria.
E) A virulent phage infects but does not destroy bacteria.

Answer 3

D

Question 4

Which of the following are RNA viruses that have a DNA polymerase?

A) Norwalk virus
B) Measles virus
C) Protein synthesis
D) DNA replication
E) Retroviruses

Question 5

Which statement describes a temperate virus?

A) A temperate virus undergoes a lytic cycle.
B) A temperate virus is considered virulent.
C) A temperate virus does not always destroy its host.
D) A temperate virus does not undergo a lysogenic cycle.
E) A temperate virus always destroys their host immediately.

Question 6

Which of the following are responsible for some very serious diseases, including Ebola hemorrhagic fever?

A) Pathogens
B) Respiratory diseases
C) Tuberculosis
D) Digestive diseases
E) Diarrheal diseases

Question 7

How are viruses classified by the ICTV?

A) By their DNA sequence
B) By their number of rRNA
C) By their structural components
D) By their host range and other characteristics
E) By the Linnaean binomial nomenclature system

Question 8

Which of the following cause disease and often death?:

A) Vaccines
B) Diarrheal diseases
C) Malaria
D) Viruses that have only a lytic cycle
E) Tuberculosis

Question 9

What are subviral agents that depend on co-infection of a host cell with a helper virus?

A) Viroids
B) Satellites
C) Prions
D) Defective interfering particles
E) Mimivirus

Question 10

What is a very small infective agent that consists of a core of nucleic acid and is dependent on a living host?

A) Protein
B) Virus
C) Cellular organism
D) Virologist
E) Glycoprotein

Question 11

What is the correct unit of measurement for the size of most viruses?

A) Picometers
B) Nanometers
C) Micrometers
D) Centimeters
E) Decimeters

Question 12

What is the protein coat of a virus called?

A) Envelope
B) Capsule
C) Capsid
D) Phage
E) Pilus

Question 13

Viral proteins can damage host cells by which process?

A) Producing endotoxins
B) Preventing transcription of viral nucleic acids
C) Increasing the rate of fermentation within the host
D) Causing a decline in coordination and increased irritability
E) Overwhelming the host cell with a large number of viruses

Question 14

What type of conversion occurs when a bacterium carrying viral genes takes on new, atypical characteristics?

A) Transducing
B) Lysogenic
C) Prophage
D) Reverse
E) Lytic

Question 15

What is a prophage?

A) It is a bacterial cell about to lyse.
B) It is an underdeveloped lytic virus.
C) It is phage DNA that is integrated into viral DNA.
D) It is phage DNA that is integrated into bacterial DNA.
E) It is when the phage is attached to the cell surface of the bacterium.

Question 16

At what stage of a lytic infection are phage components put together to make new viruses?

A) Replication and synthesis
B) Penetration
C) Attachment
D) Assembly
E) Release

Question 17

Which statement about viruses is FALSE ?

A) Viruses are not cellular.
B) Viruses can manufacture proteins.
C) Viruses cannot carry on metabolic activities.
D) Viruses can only replicate by infecting other cells.
E) Viruses have a protective protein coat called a capsid.

Question 18

What are the viruses that attack bacteria?

A) Phages
B) Virions
C) Prions
D) Satellites
E) Adenoviruses

Question 19

At what stage of the lysogenic cycle would a prophage appear?

A) Penetration
B) Integration
C) Attachment
D) Replication
E) Assembly

Question 20

Which characteristic defines a virus?

A) Viruses cannot replicate.
B) Viruses cannot metabolize.
C) Viruses contain both RNA and DNA.
D) Viruses have various morphologies.
E) Viruses are very tiny cells with nuclei.

Question 21

The genome of most plant viruses consists of what kind of RNA?

A) rRNA
B) mRNA
C) ssRNA
D) dsRNA
E) SRP RNA

Question 22

What does ss DNA stand for?

A) Single stranded DNA
B) Simple satellite DNA
C) Single synthesis DNA
D) Simple synthase DNA
E) Synthetic strand DNA

Question 23

Polydnaviruses are particles that consist of multiple circles of _______________ encased in capsid proteins and an envelope.

A) ssDNA
B) dsDNA
C) ssRNA
D) dsRNA
E) RNA

Question 24

A virus is a very small infective agent that consists of a core of nucleic acid and is dependent on a living host.

Question 25

_______________ are those that have been almost eradicated and then suddenly recur, causing an epidemic.

A) Retroviruses
B) Emerging viruses
C) Re-emerging viruses
D) Zoonotic diseases
E) RNA viruses

Question 26

Viroids cause a variety of plant diseases and are composed only of:

A) strands of RNA.
B) strands of DNA.
C) protein coats.
D) peptidoglycan.
E) a capsid.

Question 27

Which has an unusual characteristic in that their circular DNA does not have genes for making the proteins needed to replicate and produce new viruses?

A) Viroid
B) Retroviruses
C) Bacteriophages
D) Pandoraviruses
E) Polydnaviruses

Question 28

When a virus penetrates the host plasma membrane and moves into the cytoplasm it is called:

A) release.
B) adsorption.
C) penetration.
D) replication and synthesis.
E) assembly.

Question 29

Which hypothesis asserts that viruses are remnants of cellular organisms and evolved from small cells that were parasites in larger cells?

A) Escape hypothesis
B) Virus-first hypothesis
C) Regressive hypothesis
D) Progressive hypothesis
E) Degenerative hypothesis

Question 30

Briefly describe the nucleic acid core, capsid, and envelope of viruses.

Question 31

Who is credited with the discovery of prions as a new biological principle of infection?

A) Anton van Leeuwenhoek
B) Dmitrii Ivanowsky
C) Stanley Prusiner
D) Stanley Brenner
E) Carl Woese

Question 32

Briefly explain reason why the measles virus can infect many human tissues, whereas the influenza virus can infect only one type of tissue.

Question 33

The immunodeficiency virus that causes acquired immunodeficiency syndrome is an enveloped virus.

Question 34

_______________ are RNA viruses that have a DNA polymerase called reverse transcriptase, which transcribes the RNA genome into a DNA intermediate.

A) Coxsackie viruses
B) Feline caliciviruses
C) Usutu viruses
D) Tobacco etch viruses
E) Retroviruses

Question 35

Which of the following is the most common structure of a virus?

A) Polyhedral
B) Simply phages
C) Bacteriophages
D) Icosahedron
E) A long nucleic acid molecule

Question 36

According to the progressive hypothesis , viruses may have originated as mobile genetic elements such as:

A) mRNA.
B) alleles.
C) plasmids.
D) enzymes.
E) ribosomes.

Question 37

The bacterium that causes botulism disease is harmless until it:

A) is infected by prions.
B) is infected by lytic bacteria.
C) is irradiated by UV radiation.
D) contains a certain prophage DNA.
E) is infected by certain retroviruses.

Question 38

Compare a viral lytic cycle and a viral lysogenic cycle.

Question 39

How do retroviruses differ from other RNA viruses?

A) Retroviruses have a unique capsid shape.
B) Retroviruses lytically destroy their hosts.
C) Retroviruses have a unique infection technique of their host cells.
D) Retroviruses have a capsid composed of protein and carbohydrates.
E) Retroviruses have reverse transcriptase instead of RNA-dependent RNA polymerase.

Question 40

Before an animal cell's membrane fuses with a virus, the virus must first:

A) duplicate its DNA.
B) use enzymes of the plasma membrane to break down its capsid.
C) replicate itself to attack numerous sites of the plasma membrane.
D) extend its tail fibers to sense the plasma membrane of the host cell.
E) attach to a specific receptor on the plasma membrane of the host cell.

Question 41

The nucleic acid core of the virus is not surrounded by a protein coat called a capsid.

Question 42

Bacteriophages decrease food safety.

Question 43

Compare the three hypotheses that explain the evolution of viruses

Question 44

Bacteriophages attach to the cell walls of bacteria by envelope proteins.

Question 45

Bacteria protect themselves from bacteriophage infections by producing restriction enzymes that cut up foreign RNA of the phage.

Question 48

Lytic reproductive cycles destroy host cells.

Question 50

Dr. Stanley Prusiner concluded that the infective agent of CJD was not a virus because it was not sensitive to radiation, which mutates nucleic acids.

Question 53

Describe the defenses of plants against viruses and explain why infected plants are destroyed.

Question 54

An emerging virus is one that is not new to a population or that is rapidly increasing in incidence.

Question 55

Retroviruses have a DNA polymerase called reverse transcriptase, which transcribes the RNA genome into a DNA intermediate.