The most conclusive evidence that viruses cause cancers is provided by
A) finding oncogenes in viruses.
B) the presence of antibodies against viruses in cancer patients.
C) cancer that developed in chickens following injection of cell-free filtrates.
D) treating cancer with antibodies.
E) some liver cancer patients having had hepatitis.
C
The following steps occur during multiplication of retroviruses. Which is the fourth step?
A) uncoating
B) synthesis of +RNA
C) penetration
D) attachment
E) synthesis of double-stranded DNA
E
The following steps occur during multiplication of herpesviruses. Which is the third step?
A) attachment
B) biosynthesis
C) penetration
D) release
E) uncoating
E
DNA made from an RNA template will be incorporated into the virus capsid of
A) Retroviridae.
B) Herpesviridae.
C) Hepadnaviridae.
D) bacteriophage families.
E) influenzavirus.
C
Which of the following is in correct order for DNA-virus
replication?
1. Maturation
2. DNA synthesis
3.
Transcription
4. Translation
A) 4; 3; 2; 1
B)4; 1; 2; 3
C) 1; 2; 3; 4
D) 3; 4; 1; 2
E) 2; 3; 4; 1
E
Bacteriophage replication differs from animal virus replication because only bacteriophage replication involves
A) adsorption to specific receptors.
B) assembly of viral components.
C) replication of viral nucleic acid.
D) injection of naked nucleic acid into the host cell.
E) lysis of the host cell.
D
Bacteriophages and animal viruses do NOT differ significantly in which one of the following steps?
A) attachment
B) penetration
C) uncoating
D) biosynthesis
E) release
D
What contributes to antigenic shift in influenza viruses?
A) worldwide distribution of the virus
B) a segmented genome
C) attachment spikes
D) ease of virus transmission
E) different virus subtypes
B
Which of the following is NOT utilized to culture viruses?
A) laboratory animals
B) culture media
C) embryonated eggs
D) animal cell cultures
E) bacterial cultures
B
A viral species is a group of viruses that
A) has the same morphology and nucleic acid.
B) has the same genetic information and ecological niche.
C) infects the same cells and cause the same disease.
D) cannot be defined.
B
The morphological types of viruses illustrated in the figure are ultimately determined by the
A) membrane spikes.
B) nucleic acid.
C) capsomeres.
D) viroids.
E) envelope.
B
Which of the following statements about viral spikes is FALSE?
A) They are composed of carbohydrate-protein complexes.
B) They are used for attachment.
C) They may cause hemagglutination.
D) They bind to receptors on the host cell surface.
E) They are found only on nonenveloped viruses.
E
Viruses are nonliving because:
A)They cause diseases in host cells.
B) They cannot replicate outside host cells.
C) They are composed of relatively simple components.
D) They pass through filters.
E) They are not composed of cells.
E
A feature that may be found in viruses but never in bacteria is
A) an ability to infect more than one type of host.
B) the ability to pass through 0.22 micrometer pore filters.
C) a sensitivity to antibiotics.
D) may contain an RNA genome.
E) they cannot reproduce themselves outside a host.
D
An oncogene is:
A) A gene that may induce cancer
B) A viral ligand found in a family of viruses
C) A viral polymerase
D) A toxin gene transferred by a virus
E) A problematic gene found exclusively in viruses
A
Some viruses, such as human herpesvirus 1, infect a cell without causing symptoms. These are called
A) phages.
B) lytic viruses.
C) latent viruses.
D) unconventional viruses.
E) slow viruses.
C
Assume a patient has influenza. During which time on the graph in the figure would the patient show the symptoms of the illness?
A
B
C
D
E
C
A persistent infection is one in which
A) the virus remains in equilibrium with the host without causing a disease.
B) viral replication is unusually slow.
C) the disease process occurs gradually over a long period.
D) host cells are gradually lysed.
E) host cells are transformed.
C
A viroid is a(n)
A) complete, infectious virus particle.
B) infectious piece of RNA without a capsid.
C) capsid without nucleic acid.
D) provirus.
E) infectious protein.
B
An infectious protein is a
A) bacteriophage.
B) prion.
C) retrovirus.
D) viroid.
E) papovavirus.
B
Most RNA viruses carry which of the following enzymes?
A) DNA-dependent DNA polymerase
B) lysozyme
C) RNA-dependent RNA polymerase
D) reverse transcriptase
E) ATP synthase
C
A virus's ability to infect an animal cell depends primarily upon the ________.
A) host cell's ability to phagocytize viral particles
B) type of viral nucleic acid
C) enzymatic activity of a host cell
D) presence of pili on the host cell wall
E) presence of the corresponding binding receptors on the cell membrane
E