Deck 11: Viruses

Question 1

A latent viral infection is an infection in which:

A)viral replication is slow
B)viruses remains within host cells without causing a disease
C)a viral infection causes a disease progression gradually over a long period
D)viral replication has stopped but may resume years or decades later upon reactivation

Answer 1

D

Question 2

Viruses have some of the properties of cellular life forms.Which of the following is a characteristic of all organisms except viruses

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

Answer 2

A

Question 3

Viruses are referred to as obligate intracellular 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 must use the host's machinery to synthesize components required for assembly into new virus particles.

Answer 3

D

Question 4

A viral infection is treated with a drug designed to inhibit reverse transcriptase.Which of the following viruses would NOT be affected

A)Human Immunodeficiency virus
B)Murine leukemia virus
C)Hepatitis B virus
D)None of these choices

Question 5

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 6

A naked virus:

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

Question 7

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 --> mRNA --> protein
B)DNA --> protein
C)RNA --> DNA --> mRNA --> protein
D)RNA --> protein

Question 8

A minus (antisense)strand virus might synthesize proteins within a host cell through the following synthesis pathway:

A)minus strand RNA --> protein
B)minus strand RNA --> plus strand RNA --> protein
C)RNA --> DNA --> protein
D)RNA --> RNA --> DNA --> protein

Question 9

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

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

Question 10

Common colds and influenza are caused by which of the following pair of virus families

A)Adenoviridae & Orthomyxoviridae
B)Enterovirus & Retrovirus
C)Flavivirus & Rhinovirus
D)Poxvirus & Papillomavirus

Question 11

Viruses that have plus strand RNA chromosomes that acts as a template for DNA synthesis are known as:

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

Question 12

Select the true statement regarding yellow fever.

A)Yellow fever is endemic to the United States.
B)Yellow fever is only transmitted by one mosquito species.
C)Yellow fever is transmitted by ticks and mosquitoes.
D)Yellow fever is caused by a flavivirus.

Question 13

Advantages provided by the viral envelope include:

A)helping viruses infect new cells by fusion of the envelope with the host's plasma membrane.
B)helping viruses "hide" from attack by the host's immune system.
C)resistance to extreme pH (below 6 or above 8).
D)both helping viruses infect new cells by fusion of the envelope with the host's plasma membrane and helping "hide" from attack by the host's immune system.

Question 14

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

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

Question 15

Which is the best scientific explanation for the increasing concern over the recent outbreaks of avian influenza in Hong Kong and other Asian locations

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

Question 16

Which structure of the herpesvirus is represented by the arrow

A)Capsid
B)Nucleic acid core
C)Spikes
D)Envelope

Question 17

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

A)presence of an envelope
B)shape of the capsid
C)sense or antisense RNA
D)whether RNA is linear or circular

Question 18

A virus that is specific for a bacterial host is called a:

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

Question 19

Which of the following viruses are known for causing latent infections

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

Question 20

In the early 1990s,this emerging virus was of concern to the United States.It is transmitted from rodent feces and urine to human beings.This emerging virus is the:

A)influenza virus
B)rhinovirus
C)hantavirus
D)poliovirus

Question 21

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 22

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

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

Question 23

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 24

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

A)maturation --> adsorption --> penetration --> release --> synthesis
B)adsorption --> penetration --> release --> maturation --> synthesis
C)adsorption --> penetration --> synthesis --> maturation --> release
D)adsorption --> penetration --> maturation --> synthesis --> release

Question 25

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 26

Prophages are responsible for production of the toxins found in:

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

Question 27

Which of the following would be the best host system to study influenza A viruses

A)Primary cell culture
B)Diploid fibroblast strain
C)Continuous cell line
D)Embryonated chicken egg

Question 28

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 29

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 30

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

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

Question 31

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 re-isolated from animal tissues

Question 32

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 33

Identify the portion of the growth curve that represents the time after penetration through the release of mature phages.

A)A
B)B
C)C

Question 34

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

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

Question 35

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

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

Question 36

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 37

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 38

Plaques are:

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

Question 39

What type of effect is occurring with these cells infected by RSV

A)Cytopathic effect
B)CPE
C)Nuclear effect
D)Cytoplasmic effect
E)Both Cytopathic effect and CPE are correct

Question 40

Growth of a bacterium which contains a prophage represents a:

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

Question 41

A prion is composed of:

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

Question 42

Diseases such as Creutzfeld-Jacob disease (variant),kuru,and mad cow disease are caused by:

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

Question 43

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 44

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

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

Question 45

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

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 46

Viroids are composed of ______.

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

Question 47

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 48

The scientist who discovered that some viruses may cause cancer is:

A)Diener
B)Rous
C)Prusiner
D)Prioux

Question 49

An uncontrolled,invasive growth of abnormal cells is referred to as _____.

A)transduction
B)cancer
C)induction
D)transformation
E)none of these choices

Question 50

Malignant tumors and their cells can ____ to other locations and organs in the body.

A)metastasize
B)begin
C)stagnate
D)end

Question 51

A viroid has all of the following characteristics EXCEPT:

A)single circular RNA chromosome
B)need for a helper virus in replication
C)lack of protein in its structure
D)lack of DNA in its structure