Deck 10: Viruses

Question 1

Viruses have some of the properties of living organisms. Which of the following is a characteristic of all organisms,but not of viruses?

A) presence of a plasma membrane
B) capable of metabolism
C) ability to reproduce
D) grow in response to their environment conditions

Answer 1

A

Question 2

The advantage of the viral envelope includes:

A) helps viruses infect new cells by fusion of the envelope with the host's plasma membrane.
B) resists increased temperature
C) resists extreme pH (below 6 or above 8)
D) protects viruses

Answer 2

A

Question 3

DNA viruses are grouped into families based on the following characteristics except:

A) presence of an envelope
B) presence of a capsid
C) whether DNA is single stranded or double stranded
D) whether DNA is linear or circular

Answer 3

B

Question 4

The families of RNA viruses are distinguished from one another by all of the following except

A) presence of an envelope
B) presence of a capsid and its shape
C) sense or nonsense RNA
D) whether RNA is linear or circular

Question 5

Common cold and flu are caused by which of the following pair of viruses?

A) rhinovirus - orthomyxoviridae
B) enterovirus - retrovirus
C) flavivirus - rhinovirus
D) poxyvirus - papillomavirus

Question 6

The reason that retroviruses can direct the formation of DNA from RNA is because most retroviruses contain the following enzyme

A) RNA polymerase
B) DNA polymerase
C) DNA ligase
D) reverse transcriptase

Question 7

Viruses that have a single strand of RNA that acts as a template for DNA synthesis are known as

A) retroviruses.
B) proviruses.
C) viroids.
D) bacteriophages.
E) lytic phages.

Question 8

Which of the following viruses are known for causing latent infections?

A) adenoviruses
B) herpesviruses
C) poxviruses
D) parvoviruses

Question 9

You have isolated an unknown virus. It is a double-stranded DNA and does not have an envelope. To which virus family does it mostly likely belong?

A) paramyxoviridae
B) retroviridae
C) adenoviridae
D) parvoviridae

Question 10

A viral infection is ineffective by the treatment of anti-RNA drug. The most likely reason is that this virus is a

A) picornavirus
B) orthomyxovirus
C) poxvirus
D) reovirus

Question 11

Some viruses have a lipid bilayer,also known as the viral envelope. The viral envelope most likely comes from the following source:

A) host cell plasma membrane
B) host membrane bound organelles
C) host nucleus
D) another virus

Question 12

Acquired Immune Deficiency Syndrome (AIDS)is caused by a retrovirus. Which of the following best represents the genetic information flow used by retroviruses?

A) DNA à mRNA à protein
B) DNA à protein
C) RNA à DNA à mRNA à protein
D) RNA à protein

Question 13

A latent viral infection is an infection in which

A) a viral replication is slow
B) a virus remains within host cells without causing a disease
C) a viral infection causes a disease progression gradually over a long period
D) a viral replication has stopped

Question 14

A naked virus

A) has no protein wrapping around its nucleic acid.
B) is unable to attach itself to a host cell.
C) has no membranous envelope
D) has no infectious piece of DNA

Question 15

All of the following viruses may stay inside of a cell for many years and remain inactive except

A) herpes
B) chickenpox
C) HIV
D) enterovirus

Question 16

Which of the following structures do viruses use to attach themselves to the host cell and help viruses enter the host cells?

A) viral spikes
B) viral tails
C) viral particles
D) viral nucleic acid

Question 17

Viruses are referred to as obligate parasites because

A) viral DNA inserts itself into host DNA.
B) they reproduce and then exit the cell.
C) they use the host's energy to live.
D) they use the host cell's nucleotides and enzymes to reproduce.

Question 18

Viruses that infect bacteria are known as complex viruses. Which of the following diagrams represents a complex virus?

A)
B)
C)
D)

Question 19

Which of the following is not caused by a poxvirus?

A) smallpox
B) chickenpox
C) cowpox
D) monkeypox

Question 20

A virus's RNA can be directly used to synthesize proteins by the host cell after infection in a process shown below:

A) RNAà protein
B) RNAà RNA à protein
C) RNA à DNA à protein
D) RNA à RNA à DNA à protein

Question 21

Because viruses such as bacteriophages lead to bursting of the bacterial host cell they are known as ________ viruses.

A) lytic
B) lysogenic
C) recurring
D) lethal

Question 22

Viruses can be grouped into the following categories except:

A) animal viruses
B) bacterial viruses
C) plant viruses
D) fungal viruses

Question 23

Temperate phages

A) do not always undergo a lytic cycle
B) only replicate at certain temperatures
C) are those that cause disease
D) form plaques on bacterial lawns

Question 24

Reactivation of chickenpox long after the initial infection leads to the disease

A) cancer
B) influenza
C) shingles
D) varicella

Question 25

Prophages are responsible for production of the toxins found in

A) Staphylococcus aureus
B) Micrococcus luteus
C) Clostridium botulinum
D) Streptococcus lactis

Question 26

Which of the following is a FALSE statement about yellow fever?

A) endemic to the United States
B) the first human disease found to be caused by a virus
C) the first confirmation that an insect could transmit a virus
D) caused by a flavivirus
E) its first name was yellow jack

Question 27

Bacteriophages contain the enzyme lysozyme,which is used to

A) replicate viral DNA.
B) shut down bacterial cell metabolism.
C) weaken bacterial cell walls.
D) help recognize the proper bacterial host.

Question 28

Viral DNA lying within a bacterial chromosome is called a ________ while the combination of a bacterial cell and its temperate phage is called a ________.

A) prophage, lysogen
B) plaque, lysogen
C) lysogen, prophage
D) prophage, retrovirus

Question 29

Plaques are

A) bacterial colonies
B) another name for single viruses
C) areas where bacterial cells have been lysed
D) bacterial film

Question 30

A virus that is specific for a bacterial host is called

A) phage
B) prion
C) viroid
D) virion

Question 31

The virus that causes human severe acute respiratory syndrome (SARS)infects all of the following except

A) humans
B) dogs and cats
C) birds
D) snakes

Question 32

Growth of a bacterium which contains a prophage represents a

A) lytic cycle
B) temperate cycle
C) lysogenic cycle
D) induction

Question 33

Why is there concern about the recent outbreak of avian influenza in Netherlands? Because

A) avian influenza may infect humans.
B) human influenza may exchange genetic material with avian influenza and infect humans.
C) avian influenza may spread to other countries.
D) avian influenza may change to another virus that could infect humans.

Question 34

Which of the following is used by negative strand RNA viruses such as measles and influenza during their replication cycle?

A) synthesize DNA via reverse transcriptase
B) synthesize a double stranded RNA intermediate
C) synthesize an RNA:DNA hybrid whose RNA is a (+) strand
D) synthesize an RNA:DNA hybrid whose DNA is a (-) strand

Question 35

Which of the following represents the correct order of steps in a typical virus replication cycle?

A) maturation à adsorption à penetration à release
B) adsorption à penetration à release à maturation
C) adsorption à penetration à synthesis à maturation
D) adsorption à penetration à maturation à synthesis

Question 36

Bacteriophage DNA is transcribed to mRNA during the ________ phase of viral replication.

A) penetration
B) synthesis
C) maturation
D) release

Question 37

What would be a reasonable number of new phages to expect from one round of viral replication in one cell?

A) 2
B) 100
C) 1000
D) 10000

Question 38

Severe acute respiratory syndrome (SARS)is a viral respiratory illness that was first reported in Asia in 2003. Which of the following viruses was identified as the cause for SARS in humans?

A) Coronaviruses
B) Enterovirus
C) Filovirus
D) Rotavirus

Question 39

Assembly of new viral components into a complete virion takes place during viral

A) maturation
B) adsorption
C) penetration
D) synthesis

Question 40

Much of the information about how viruses work has been gleaned from studying T even phages that infect

A) bacteria
B) human cells
C) mammalian cells
D) plant cells

Question 41

Why was it previously believed that only DNA viruses can cause cancer? How can RNA viruses cause cancer?

Question 42

The only RNA tumor virus that causes human cancer is

A) retroviruses
B) proviruses
C) rhinovirus
D) rubella virus

Question 43

Viroids are composed of

A) single infectious proteins
B) double stranded RNA
C) single-stranded linear DNA
D) single-stranded circular RNA

Question 44

A drug or other agent that induces defects during embryonic development is known as a

A) syncytia
B) capsomere
C) teratogen
D) carcinogen

Question 45

A rare form of cancer that has become common among men with AIDS is

A) Kaposi's sarcoma
B) Pneumocystis carinii pneumonia
C) tuberculosis
D) Burkitt's lymphoma

Question 46

Diseases such as Creutzfeld-Jacob disease,kuru,and mad cow disease are caused by

A) RNA viruses
B) DNA viruses
C) bacteria
D) prions

Question 47

How are computer viruses similar to and different from biological viruses? Are computer viruses alive? Why or why not?

Question 48

Which of the following explains how DNA tumor viruses may cause human cancers?

A) viral proteins infect other uninfected host cells
B) viral proteins block the effect of tumor-suppressor genes which prevent uncontrolled cell division
C) viral particles infect sex cells and transmit the virions to offspring.
D) use viral reverse transcriptase to integrate the DNA tumor viruses into the host chromosome

Question 49

Which of the following viruses plays an important role in the development of cervical cancer?

A) adenoviruses
B) herpes viruses
C) papilloma viruses
D) slow viruses

Question 50

Cells taken directly from an animal and cultured in vitro represent

A) primary cell cultures
B) diploid fibroblast strains
C) continuous cell lines from human embryos
D) continuous cell lines that have been reisolated from animal tissues

Question 51

All of the following reasons explain why eggs are often used to grow animal viruses except

A) eggs are large cells
B) eggs are sterile
C) eggs contain a number of sites that are suitable for viral replication
D) eggs are easy to store

Question 52

Why did scientists initially resist the idea of an infectious,self-replicating protein?

Question 53

Enveloped animal viruses typically leave the host cell by

A) host cell lysis
B) host cell rupture
C) budding
D) animal viruses never leave the host cell

Question 54

The most conclusive evidence that viruses cause cancers is provided by the following:

A) the presence of oncogenes in humans
B) the presence of antibodies against viruses in cancer patients
C) treating cancer patients with antibiotics
D) development of a cancer following an injection of viruses

Question 55

A prion is made of which of the following?

A) RNA
B) DNA
C) proteins
D) both DNA and RNA

Question 56

Recognition of the proper host cell by an animal virus may be aided by the ________ of the virus.

A) spikes
B) tail fibers
C) DNA
D) cell membrane

Question 57

A lysogenous phage which enters a lytic cycle is said to have undergone

A) transformation
B) induction
C) transcription
D) lysogenic conversion

Question 58

Some liver cancer patients are found to have had chronic liver infection. The most likely cause of this infection is by

A) adenoviruses
B) herpesviruses
C) hepadnaviruses
D) parvoviruses