Microbiology Test 4
An example of a latent viral infection is
cold sores.
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 NOT utilized to culture viruses?
culture media
Assume a patient had chickenpox (human herpesvirus 3) as a child. Which line on the graph in Figure 13.2 would show the number of viruses present in this person as a 60-year-old with shingles (human herpesvirus 3)?
e
T/F: A viroid is a completely developed infectious agent composed of nucleic acid and surrounded by a capsid.
false
T/F: Binomial nomenclature is used to name viruses.
false
T/F: Glycoprotein spikes are found on the capsids of all viruses.
false
T/F: Helical and icosahedral are terms used to describe the shapes of a virus envelope.
false
T/F: Viruses are the only known infectious agents that are obligatory intracellular parasites.
false
A viral species is a group of viruses that
has the same genetic information and ecological niche.
Lysogeny can result in all of the following EXCEPT
immunity to reinfection by any phage.
A viroid is a(n)
infectious piece of RNA without a capsid.
Bacteriophage replication differs from animal virus replication because only bacteriophage replication involves
injection of naked nucleic acid into the host cell.
Some viruses, such as human herpesvirus 1, infect a cell without causing symptoms. These are called
latent viruses.
Bacteriophages derive all of the following from the host cell EXCEPT
lysozyme.
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
A persistent infection is one in which
the disease process occurs gradually over a long period.
Assume you have isolated an unknown virus. This virus has a single, positive sense strand of RNA, and possesses an envelope. To which group does it most likely belong?
togavirus
T/F: A segmented genome can result in antigenic shift.
true
T/F: Dogs do not get measles because their cells lack the correct receptor sites for that virus.
true
T/F: Most drugs that interfere with viral multiplication also interfere with host cell function.
true
T/F: Positive sense RNA strands of viruses are treated like mRNA inside the host cell.
true
T/F: The basic mechanism of viral multiplication is similar for all viruses.
true
The following steps occur during multiplication of herpesviruses. Which is the third step?
uncoating
Which of the following statements is NOT true of lysogeny?
It causes lysis of host cells.
Most RNA viruses carry which of the following enzymes?
RNA-dependent RNA polymerase
Which of the following statements is FALSE?
The prophage makes the host cell immune to infection by other phages.
How do all viruses differ from bacteria?
Viruses are not composed of cells.
Which of the following statements about viruses is FALSE?
Viruses use their own catabolic enzymes.
Oncogenic viruses
cause tumors to develop.
Which of the following places these items in the correct order for DNA-virus replication? 1. Maturation 2. DNA synthesis 3. Transcription 4. Translation
2; 3; 4; 1
In Figure 13.1, which structure is a complex virus?
B
The structures illustrated in Figure 13.1 are composed of
Capsomeres.
Which of the following is most likely a product of an early gene?
DNA polymerase
Generally, in an infection caused by a DNA-containing virus, the host animal cell supplies all of the following EXCEPT
DNA polymerase.
Viruses that utilize reverse transcriptase belong to the virus families
Hepadnaviridae and Retroviridae.
DNA made from an RNA template will be incorporated into the virus capsid of
Hepadnaviridae.
________ were first identified in cancer-causing viruses and can induce ________ in infected cells.
Oncogenes; transformation
Which of the following is necessary for replication of a prion?
PrPSc
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.
Which of the following statements about viral spikes is FALSE?
They are found only on nonenveloped viruses.
Which of the following statements provides the most significant support for the idea that viruses are nonliving chemicals?
They cannot reproduce themselves outside a host.
What contributes to antigenic shift in influenza viruses?
a segmented genome
Which of the following is NOT used as a criterion to classify viruses?
biochemical tests
Bacteriophages and animal viruses do NOT differ significantly in which one of the following steps?
biosynthesis
The mechanism whereby an enveloped virus leaves a host cell is called
budding.
Assume a patient has influenza. During which time on the graph in Figure 13.2 would the patient show the symptoms of the illness?
c
The most conclusive evidence that viruses cause cancers is provided by
cancer following injection of cell-free filtrates.
The definition of lysogeny is
phage DNA is incorporated into host cell DNA.
A clear area against a confluent "lawn" of bacteria is called a
plaque.
A virus ability to infect an animal cell depends primarily upon the
presence of receptor sites on the cell membrane.
An infectious protein is a
prion.
An envelope is acquired during which of the following steps?
release
The following steps occur during biosynthesis of a + strand RNA virus. What is the third step?
synthesis of - strand RNA
Which one of the following steps does NOT occur during multiplication of a picornavirus?
synthesis of DNA
The following steps occur during multiplication of retroviruses. Which is the fourth step?
synthesis of double-stranded DNA
