How do all viruses differ from bacteria?
-Viruses are not composed of cells.
-Viruses are filterable.
-Viruses are obligate intracellular parasites.
-Viruses do not have any nucleic acid.
-Viruses do not reproduce.
Viruses are not composed of cells.
A feature that may be found in viruses but never in bacteria is
-an ability to infect more than one type of host.
-they cannot reproduce themselves outside a host.
-the ability to pass through 0.22 micrometer pore filters.
-may contain an RNA genome.
-a sensitivity to antibiotics.
may contain an RNA genome.
Which of the following statements about viral spikes is FALSE?
-They may cause hemagglutination.
-They bind to receptors on the host cell surface.
-They are found only on nonenveloped viruses.
-They are used for attachment.
-They are composed of carbohydrate-protein complexes.
They are found only on nonenveloped viruses.
Which of the following is NOT used as a criterion to classify viruses?
biochemical tests
Which of the following is NOT utilized to culture viruses?
culture media
Bacteriophages and animal viruses do NOT differ significantly in which one of the following steps?
biosynthesis
The definition of lysogeny is
phage DNA is incorporated into host cell DNA.
A viroid is a(n)
infectious piece of RNA without a capsid.
In Figure 13.1, which structure is a complex virus?
b
The morphological types of viruses illustrated in Figure 13.1 are ultimately determined by the
nucleic acid.
A clear area against a confluent "lawn" of bacteria is called a
plaque.
Continuous cell lines differ from primary cell lines in that
continuous cell lines can be maintained through an indefinite number of generations.
Which of the following is necessary for replication of a prion?
PrPSc
A persistent infection is one in which
the disease process occurs gradually over a long period.
An example of a persistent viral infection is
Varicellavirus infection.
Lysogeny can result in all of the following EXCEPT
immunity to reinfection by any phage.
Which of the following would be the first step in biosynthesis of a virus with a - (minus) strand of RNA?
synthesis of double-stranded RNA from an RNA template
An infectious protein is a
prion.
An envelope is acquired during which of the following steps?
release
Which of the following statements is NOT true of lysogeny?
It causes lysis of host cells.
An example of a latent viral infection is
cold sores.
A virus's ability to infect an animal cell depends primarily upon the
presence of receptor sites on the cell membrane.
An unknown virus with a single, positive sense strand of RNA and an envelope most likely belongs to which group?
togavirus
The mechanism whereby an enveloped virus leaves a host cell is called
budding.
The most conclusive evidence that viruses cause cancers was provided by
cancer that developed in chickens following injection of cell-free filtrates.
Bacteriophages derive all of the following from the host cell EXCEPT
lysozyme.
Bacteriophage replication differs from animal virus replication because only bacteriophage replication involves
injection of naked nucleic acid into the host cell.
Generally, in an infection caused by a DNA-containing virus, the host animal cell supplies all of the following EXCEPT
DNA polymerase.
Which of the following places these items in the correct order for DNA-virus replication?
2; 3; 4; 1 (DNA synthesis, Transcription, Translation, Maturation)
A viral species is a group of viruses that
has the same genetic information and ecological niche.
Viruses that utilize reverse transcriptase belong to which virus families?
Hepadnaviridae and Retroviridae.
DNA made from an RNA template will be incorporated into the virus capsid of
Hepadnaviridae.
Which of the following statements about viruses is FALSE?
Viruses use their own catabolic enzymes.
A lytic virus has infected a patient. Which of the following would best describe what is happening inside the patient?
The virus is causing the death of the infected cells in the patient.
Some viruses, such as human herpesvirus 1, infect a cell without causing symptoms. These are called
latent viruses.
Which line on the graph in Figure 13.2 would show the number of viruses present in a person with shingles (human herpesvirus 3)?
e
During which time on the graph in Figure 13.2 would a patient with influenza show symptoms?
c
The third step in the multiplication of herpesviruses is
uncoating.
The fourth step in the multiplication of retroviruses is
synthesis of double-stranded DNA.
Oncogenic viruses
cause tumors to develop.
Which one of the following steps does NOT occur during multiplication of a picornavirus?
synthesis of DNA
Which of the following is most likely a product of an early gene?
DNA polymerase.
Most RNA viruses carry which of the following enzymes?
RNA-dependent RNA polymerase.
What is NOT true regarding viruses that infect plants?
They are often cultured in embryonated chicken eggs.
What contributes to antigenic shift in influenza viruses?
a segmented genome.
________ were first identified in cancer-causing viruses and can induce ________ in infected cells.
Oncogenes; transformation.
What is an oncogene?
an altered form of a gene that may induce cancer.
What is the key characteristic of a transformed cell?
has acquired tumor-forming properties.
Shingles is an example of
reactivation of latent virus.
Why do most scientists agree that viruses are nonliving entities?
They are not composed of cells.