Deck 1: General Virology

Question 1

The proteins on the external surface of viruses serve several important functions. Regarding these proteins, which one of the following statements is most accurate?

A) They are the antigens against which neutralizing antibodies are formed.
B) They are the polymerases that synthesize viral messenger RNA.
C) They are the proteases that degrade cellular proteins leading to cell death.
D) They are the proteins that regulate viral transcription.
E) Change in conformation of these proteins can result in prion-mediated diseases such as Creutzfeldt-Jakob disease.

Answer 1

A

Question 2

If a virus has an envelope, it is more easily inactivated by lipid solvents and detergents than viruses that do not have an envelope. Which one of the following viruses is the most sensitive to inactivation by lipid solvents and detergents?

A) adenovirus
B) Hepatitis A virus
C) Herpes simplex virus
D) Coronavirus
E) Rotavirus

Answer 2

D

Question 3

All of the following is correct as regard viruses Except

A) They can infect humans ,animals, plants and bacteria
B) They lack machinery for protein and energy production
C) They are obligate intracellular parasites only replicate inside living cells using cell biological machinery
D) They can grow on artificial medium

Answer 3

D

Question 4

Many viruses are highly specific regarding the type of cells they infect. Of the following, which one is the most important determinant of this specificity?

A) The matrix protein
B) The polymerase in the virion
C) The protease protein
D) The surface glycoprotein
E) The viral mRNA

Question 5

Your summer research project is to study the viruses that cause upper respiratory tract infections. You have isolated a virus from a patient's throat and find that its genome is RNA. Furthermore, you find that the genome is the complement of viral mRNA within the infected cell. Of the following, which is the most appropriate conclusion you could draw?

A) The genome RNA is infectious.
B) The genome RNA is segmented.
C) The virion contains a polymerase.
D) The virion has a lipoprotein envelope.
E) A single-stranded DNA is synthesized during replication.

Question 6

The purified genome of certain viruses can enter a cell and elicit the production of progeny viruses (i.e., the genome is infectious). Regarding these viruses, which one of the following statements is most accurate?

A) Their genome RNA has positive polarity.
B) Their genome RNA is double-stranded.
C) They have a polymerase in the virion.
D) They have a segmented genome.
E) They require tegument proteins in order to be infectious.

Question 7

Regarding viral replication, which one of the following is most accurate?

A) The cytopathic effect typically occurs during the eclipse period.
B) The early proteins are typically enzymes, whereas the late proteins are typically capsid proteins.
C) The assembly of a nonenveloped virus typically occurs as the virion buds from the cell membrane.
D) Influenza viruses synthesize their mRNA using host cell-encoded RNA-dependent RNA polymerase.
E) Retroviruses (e.g., HIV) synthesize their mRNA using an enzyme in the virion called reverse transcriptase.

Question 8

Each of the following statements concerning retroviruses is correct EXCEPT:

A) The virion carries an RNA-directed DNA polymerase encoded by the viral genome.
B) The viral genome consists of three segments of double-stranded RNA.
C) The virion is enveloped and enters cells via an interaction with specific receptors on the host cell.
D) During infection, the virus synthesizes a DNA copy of its RNA, and this DNA becomes covalently integrated into host cell DNA

Question 9

Which one of the following choices names two viruses that both translate their messenger RNA into precursor polypeptides that must be cleaved by virion-encoded proteases?

A) Herpes simplex virus and human papillomavirus
B) Human immunodeficiency virus and poliovirus
C) Influenza virus and measles virus
D) Rabies virus and hepatitis B virus
E) Rotavirus and parvovirus

Question 10

Which one of the following statements about virion structure and assembly is CORRECT?

A) Most viruses acquire surface glycoproteins by budding through the nuclear membrane.
B) Helical nucleocapsids are found primarily in DNA viruses.
C) The symmetry of virus particles prevents inclusion of any nonstructural proteins, such as enzymes.
D) Enveloped viruses use a matrix protein to mediate interactions between viral glycoproteins and structural proteins in the nucleocapsid.

Question 11

Each of the following statements concerning viruses is correct EXCEPT:

A) Viruses can reproduce only within cells.
B) The proteins on the surface of the virus mediate the entry of the virus into host cells.
C) Neutralizing antibody is directed against proteins on the surface of the virus.
D) Viruses replicate by binary fission.

Question 12

Viruses are obligate intracellular parasites. Each of the following statements concerning this fact is correct EXCEPT:

A) Viruses cannot generate energy outside of cells.
B) Viruses cannot synthesize proteins outside of cells.
C) Viruses must degrade host cell DNA in order to obtain nucleotides.
D) Enveloped viruses require host cell membranes to obtain their envelopes.

Question 13

The ability of a virus to produce disease can result from a variety of mechanisms. Which one of the following mechanisms is LEAST likely?

A) Cytopathic effect in infected cells
B) Malignant transformation of infected cells
C) Immune response to virus-induced antigens on the surface of infected cells
D) Production of an exotoxin that activates adenylate cyclase

Question 14

Each of the following statements concerning viral surface proteins is correct EXCEPT:

A) They elicit antibody that neutralizes infectivity of the virus.
B) They determine the species specificity of the virus-cell interaction.
C) They participate in active transport of nutrients across the viral envelope membrane.
D) They protect the genetic material against nucleases.

Question 15

Many viruses mature by budding through the outer membrane of the host cell. Each of the following statements regarding these viruses is correct EXCEPT:

A) Some of these viruses cause multinucleated giant cell formation.
B) Some new viral antigens appear on the surface of the host cell.
C) Some of these viruses contain host cell lipids.
D) Some of these viruses do not have an envelope

Question 16

Viruses enter cells by adsorbing to specific sites on the outer membrane of cells. Each of the following statements regarding this event is correct EXCEPT:

A) The interaction determines the specific target organs for infection.
B) The interaction determines whether the purified genome of a virus is infectious.
C) The interaction can be prevented by neutralizing antibody.
D) If the sites are occupied, interference with virus infection occurs

Question 17

Each of the following statements concerning viral serotypes is correct EXCEPT:

A) In naked nucleocapsid viruses, the serotype is usually determined by the outer capsid proteins.
B) In enveloped viruses, the serotype is usually determined by the outer envelope proteins, especially the spike proteins.
C) Some viruses have multiple serotypes.
D) Some viruses have an RNA polymerase that determines the serotype

Question 18

The ability of a virus to produce disease can result from a variety of mechanisms. Which one of the following mechanisms is LEAST likely?

A) Cytopathic effect in infected cells
B) Malignant transformation of infected cells
C) Immune response to virus-induced antigens on the surface of infected cells
D) Production of an exotoxin that activates adenylate cyclase

Question 19

All the following is correct as regard viral envelope except

A) It is a lipid in nature
B) Usually acquired from membrane of the host cell
C) It is acquired during budding of the virus from the host cell
D) it is resistant to destruction by alcohol

Question 20

All of the following is true about viruses except

A) They can infect humans, animals, plants and bacteria
B) They lack machinery for protein and energy production
C) They are obligate intracellular parasites
D) Contain both DNA and RNA

Question 21

All of the following is correct as regard DNA virues replication Except

A) All DNA viruses use host cell DNA dependant RNA polymerase to form mRNA except pox virus.
B) The genome of all DNA viruses consists of double-stranded DNA, except for the parvoviruses
C) All DNA viruses replicate in the cytoplasm Except pox virus
D) They needs to make mRNAs that can be translated into protein using host cell translation machinery

Question 22

Write the scientific term.
-Composed of small protein subunits called capsomers and responsible for the virion symmetry.

Question 23

Write the scientific term.
-Lipid or lipoprotein layer from which projecting glycoprotein likespikes

Question 24

Write the scientific term.
-Viruses that cannot replicate without a helper virus which provide a missing function may be deleted from the genome.

Question 25

Write the scientific term.
-Infectious Agents lack any genes and are composed only of protein and responsible for some transmissible spongi-form encephalopathies.

Question 26

Write the scientific term.
-Method of release of enveloped viruses, through the outer cell membrane or nuclear membrane and acquire their envelopes

Question 27

Mention one function of each of the following.
-Virus capsid

Question 28

Mention one function of each of the following.
-Virus envelope

Question 29

Mention one function of each of the following.
-Matrix proteins

Question 30

Give reason for each of the following.
-All DNA viruses use host cell DNA dependant RNA polymerase to form mRNA except pox virus.