Question 1

Infectious protein particles are called ______.

Accepted Answer

A)  viroids
B)  phages
C)  prions
D)  oncogenic viruses
E)  spikes

Question 2

Viral classification has changed over the years and while they are given genus names, the use of species names has not been widely accepted.This is because

Accepted Answer

A)  viruses are not organisms.
B)  viruses change over time making species characteristics difficult to stabilize.
C)  viruses that could be classified into a single species may have many, but not all, properties in common.
D)  All of the above are arguments against using species designations for viruses.

Question 3

Satellite viruses are

Accepted Answer

A)  also called viroids.
B)  dependent on other viruses for replication.
C)  the cause of spongiform encephalopathies.
D)  significant pathogens of plants.

Question 4

Who developed a rabies vaccine after realizing the disease was caused by something smaller than a bacterium?

Accepted Answer

A)  Leeuwenhoek
B)  Koch
C)  Pasteur
D)  Cohn
E)  Ivanovski

Question 5

Visible, clear, well-defined patches in a monolayer of virus-infected cells in a culture are called ______.

Accepted Answer

A)  patches
B)  buds
C)  plaques
D)  cytopathic effects
E)  pocks

Question 6

The activation of a prophage is called ______.

Accepted Answer

A)  activation
B)  lysogeny
C)  transformation
D)  induction
E)  adsorption

Question 7

Viruses ______.

Accepted Answer

A)  cannot be seen in a light microscope
B)  are prokaryotic
C)  contain 70S ribosomes
D)  undergo binary fission

Question 8

Infectious naked strands of RNA that affect plants are called ______.

Accepted Answer

A)  viroids
B)  phages
C)  prions
D)  oncogenic viruses
E)  spikes

Question 9

Antiviral drugs are often difficult to develop, largely because

Accepted Answer

A)  viruses are obligate intracellular parasites so the drugs must enter the host cell and often cause toxic side effects in order to destroy the virus.
B)  viruses are more abundant in the body than bacterial cells.
C)  viruses are much smaller than bacterial cells.
D)  viruses are more pathogenic than bacterial cells.

Question 10

Persistent viruses that can reactivate periodically are ______.

Accepted Answer

A)  chronic latent viruses
B)  oncoviruses
C)  syncytia
D)  inclusion bodies
E)  cytopathic

Question 11

Viruses mutate, and some viruses have not been discovered.

Accepted Answer

A) True 
 B)False

Question 12

Compared to bacteria that have a typical size range between 1-10  μ\muμ m,

Accepted Answer

A)  viruses range in size between 20-200 nm and are much larger than bacterial cells.
B)  viruses have a much greater size range; between 22 nm and 1000 nm.
C)  all viruses are 22 nm.
D)  viruses are larger and are blocked by sterilizing filters.

Question 13

Cells grown in culture form a/an ______.

Accepted Answer

A)  monolayer
B)  bilayer
C)  aggregate
D)  plaque

Question 14

Sterilizing filters have a pore size of 0.22  μ\muμ m.Which of the following statements is true?

Accepted Answer

A)  Bacterial cells are typically between 1,000-10,000 nm and pass through the filter, whereas most viruses are between 20 and 200 nm and are therefore blocked.
B)  Bacterial cells are typically between 1-10  μ\muμ m and pass through the filter, whereas most viruses are between 20 and 200 nm and are therefore blocked.
C)  Bacterial cells are typically between 1-10  μ\muμ m and are blocked by the filter, whereas most viruses are between 20 and 200 nm and therefore pass through.
D)  Bacterial cells are typically between 1-10 nm and are blocked by the filter, whereas most viruses are between 20 and 200  μ\muμ m and therefore pass through.

Question 15

A treatment for bacterial infections from the early 20th century has made a comeback; the use of bacterial viruses to eliminate bacterial infections.Which explanation most accurately describes the reason for the return of this treatment?

Accepted Answer

A)  A wide variety of bacteria cause a large percentage of human infections, producing much sickness and death.
B)  Viruses can infect bacteria, transferring pathogenic genes; the viral genes can then be suppressed, causing the bacteria to not replicate viruses.
C)  The attachment structures on the virus and the receptors on the host cells make for exquisite specificity of viruses for particular bacterial species.
D)  Antibiotic resistance in bacteria is on the increase, so using a different kind of therapy offers an alternative to traditional drugs.

Question 16

A/an _____ is the protein shell around the nucleic acid core of a virus.

Accepted Answer

A)  capsomere
B)  capsid
C)  spike
D)  envelope
E)  monolayer

Question 17

Viruses with _____-sense RNA contain the correct message for translation, while viruses with _____-sense RNA must first be converted into a correct message.

Accepted Answer

A)  positive; negative
B)  negative; positive
C)  primary; secondary
D)  secondary; primary
E)  intermediate; primary

Question 18

Creutzfeldt-Jacob disease is

Accepted Answer

A)  caused by a chronic latent virus.
B)  initiated by an oncogenic virus.
C)  caused by a viroid.
D)  a spongiform encephalopathy of humans.
E)  also called "mad cow disease."

Question 19

Why do some animal viruses have an external envelope, while bacteriophages never do?

Accepted Answer

A)  Some animal viruses bud out, taking part of the plasma membrane with them, whereas phages always lyse the host bacterial cell when they exit.
B)  When bacteriophages bud out, the plasma membrane is beneath the cell wall and therefore cannot be removed.
C)  When animal cells are lysed, part of the plasma membrane attaches to the virus; in bacterial cells, it is covered by the cell wall.
D)  When phages bud out of the host bacterial cell, they take with them part of the cell wall which forms the capsid, not an envelope.

Question 20

Which of the following is not a typical capsid shape?

Accepted Answer

A)  Tetrahedral
B)  Complex
C)  Helical
D)  Icosahedron

Exam 6: An Introduction to the Viruses

Viruses mutate, and some viruses have not been discovered.

Correct AnswerverifiedShow Answer

A treatment for bacterial infections from the early 20th century has made a comeback; the use of bacterial viruses to eliminate bacterial infections.Which explanation most accurately describes the reason for the return of this treatment?

Correct AnswerverifiedShow Answer

Antiviral drugs are often difficult to develop, largely because

Correct AnswerverifiedShow Answer

Infectious naked strands of RNA that affect plants are called ______.

Correct AnswerverifiedShow Answer

Compared to bacteria that have a typical size range between 1-10 μ\muμ m,

Correct AnswerverifiedShow Answer

Persistent viruses that can reactivate periodically are ______.

Correct AnswerverifiedShow Answer

Visible, clear, well-defined patches in a monolayer of virus-infected cells in a culture are called ______.

Correct AnswerverifiedShow Answer

Infectious protein particles are called ______.

Correct AnswerverifiedShow Answer

Which of the following is not a typical capsid shape?

Correct AnswerverifiedShow Answer

Cells grown in culture form a/an ______.

Correct AnswerverifiedShow Answer

Viral classification has changed over the years and while they are given genus names, the use of species names has not been widely accepted.This is because

Correct AnswerverifiedShow Answer

Creutzfeldt-Jacob disease is

Correct AnswerverifiedShow Answer

Satellite viruses are

Correct AnswerverifiedShow Answer

Who developed a rabies vaccine after realizing the disease was caused by something smaller than a bacterium?

Correct AnswerverifiedShow Answer

A/an _____ is the protein shell around the nucleic acid core of a virus.

Correct AnswerverifiedShow Answer

The activation of a prophage is called ______.

Correct AnswerverifiedShow Answer

Sterilizing filters have a pore size of 0.22 μ\muμ m.Which of the following statements is true?

Correct AnswerverifiedShow Answer

Viruses with _____-sense RNA contain the correct message for translation, while viruses with _____-sense RNA must first be converted into a correct message.

Correct AnswerverifiedShow Answer

Why do some animal viruses have an external envelope, while bacteriophages never do?

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Viruses ______.

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Compared to bacteria that have a typical size range between 1-10 $\mu$ m,

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Sterilizing filters have a pore size of 0.22 $\mu$ m.Which of the following statements is true?

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Viruses with _-sense RNA contain the correct message for translation, while viruses with _-sense RNA must first be converted into a correct message.

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