Mastering Microbiology Ch 13
How do normal prion proteins (PrP) differ from the infectious prion proteins?
Normal PrP have alpha-helices; infectious PrP have beta-pleated sheets.
How does the number of infectious prions increase?
Prions transform normal proteins into the misfolded beta-pleated sheet configuration; therefore, prions multiply by conversion.
Why are the beta-pleated multimers of PrP potentially pathogenic?
The multimers are more stable and resistant to protease.
Which of the following statements about viral spikes is FALSE?
They are found only on nonenveloped viruses.
The normal function of the PrP protein in mammals is believed to be:
assisting in normal synaptic development and function.
Oncogenic viruses
cause tumors to develop.
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.
Which one of the following steps does NOT occur during multiplication of a picornavirus?
synthesis of DNA
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
Select strategies that are likely to interfere with viral infection and replication but will NOT damage the normal functioning of host cells. Select all that apply.
- blocking attachment sites on the virus surface - blocking host cell receptors that serve as sites for viruses to attach - inhibiting viral-encoded DNA polymerase - inhibiting viral assembly and maturation processes - inhibiting the release of viruses from the host cell
Viruses that utilize reverse transcriptase belong to the virus families
Hepadnaviridae and Retroviridae.
A viroid is a(n)
infectious piece of RNA without a capsid.
A clear area against a confluent "lawn" of bacteria is called a
plaque
A virus first interacts with a host cell during the attachment process that precedes viral entry into the cell. Which of the following are possible consequences of the specific interaction between viral attachment sites and host cell surface receptors? Select all that apply.
-A particular virus may be able to infect humans but not mice. -A particular virus may be able to infect a liver cell but not a lung cell. -Some people are naturally (innately) resistant to certain viral infections. -Viral infection of a cell may be prevented by blocking the attachment sites on a virus with antibody. -Viral infection of a cell may be prevented by blocking the receptor sites on a host cell.