CH 13 HW

Which of the following is true concerning a lysogenic viral replication cycle?

During lysogeny, the viral genome integrates into the host DNA, becoming a physical part of the chromosome.

Which of the following statements concerning viruses is true?

The "host range" for a virus is determined by the presence or absence of particular components on the surface of a host cell that are required for the virus to attach.

What occurs during viral uncoating?

The capsid breaks apart, releasing the viral genome.

The normal function of the PrP protein in mammals is believed to be

assisting in normal synaptic development and function.

In what year did Stanley Prusiner discover prions?

1982

Which of the following is true regarding cultivation and isolation of animal viruses?

Diploid cell culture lines, developed from human embryos, are widely used for culturing viruses that require a human host.

Which of the following statements regarding latent viral infections is true?

Latent infections can persist for years in an individual without causing any symptoms.

How do normal prion proteins (PrP) differ from the infectious prion proteins?

Normal PrP have alpha-helices; infectious PrP have beta-pleated sheets.

Which of the following statements concerning prion diseases is true?

Normal host cellular prion proteins (PrPC) are converted into scrapie proteins (PrPSc)

How does the number of infectious prions increase?

Prions transform normal proteins into the misfolded beta-pleated sheet configuration; therefore, prions multiply by conversion.

From which phrase is the term "prions" derived?

Proteinaceous infectious particles

Which disease did Stanley Prusiner first identify as being caused by prions?

Scrapie

Which statement concerning viral structure is true?

Spikes are found on some viruses. They are very consistent in structure and can be used for identification.

What happens to the packaged DNA of a specialized transduced phage when it infects a new recipient cell?

The host DNA integrates, with the prophage, into the new recipient chromosome.

Why are the beta-pleated multimers of PrP potentially pathogenic?

The multimers are more stable and resistant to protease.

How does specialized transduction differ from regular lysogeny?

The prophage in specialized transduction carries with it pieces of the host chromosomal DNA.

How can specialized transduction contribute to the transfer of antibiotic resistance genes in a bacterial population?

The prophage takes an antibiotic resistance gene with it and is packaged with the newly synthesized viral DNA.

How are prions different from other infectious agents?

They lack nucleic acid.

How are viruses different from cells?

They require a host in order to reproduce.

What is the function of the structural elements of a virus?

To package and protect the viral genome

Which of the following is true of viroids?

Viroids are short pieces of naked RNA.

We sometimes are able to generate antibodies (immune system proteins) that bind to and cover up some of the proteins on the outermost portion of a virus while it is in the bloodstream. This renders the virus unable to reproduce. Which step of viral replication are antibodies directly preventing?

attachment

Enveloped viruses have a layer of lipids surrounding their capsid. This envelope is made mostly of host cell membrane. In which step does the virus acquire this envelope?

release