How does specialized transduction differ from regular lysogeny? |
The prophage in specialized transduction carries with it pieces of the host chromosomal DNA. |
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 |
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. |
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. |
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 |
How do naked viruses differ from enveloped viruses in their attachment/penetration phase? |
Their nucleic acids are injected into the cell. |
Which virus employs the use of an RNA-dependent RNA polymerase? |
+RNA viruses |
Which of the following viruses is transcribed from RNA to DNA to RNA during the replication cycle? |
Retroviruses |
Which type of virus would produce viral glycoproteins to be expressed on the host cell membrane? |
Enveloped viruses |
Which of the following can be used directly as messenger RNA? |
+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 |
What occurs during viral uncoating? |
the capsid breaks apart, releasing the viral genome |
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 |
From which phrase is the term "prions" derived? |
Proteinaceous infectious particles |
In what year did Stanley Prusiner discover prions? |
1982 |
Which disease did Stanley Prusiner first identify as being caused by prions? |
Scrapie |
How are prions different from other infectious agents? |
They lack nucleic acid |
The normal function of the PrP protein in mammals is believed to be: |
assisting in normal synaptic development and function. |
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 best describes Barbara's condition? |
shingles caused by the herpes zoster virus |
What is the correct sequence of events for the replication of a DNA virus? |
1. virions attach to the host cells. 2. viral DNA is released into the nucleus of the host cell 3. enzymes required for multiplication of viral DNA are produced via transcription and translation 4. a copy of the DNA is made 5. capsid and other structural proteins are manufactured 6. virions are assembled to form complete viruses and are released from the host cell |
Which of the following factors could have contributed to Barbara's development of shingles? |
-her daughter and grandchildren moving into her house shortly after the death of her husband -her age, 68 |
Barbara is worried about spending time with her grandchildren while being treated for shingles. Can her grandchildren contract chickenpox or shingles from spending time with their grandmother? |
No. Because of their ages, the grandchildren have most likely been vaccinated against the chickenpox. They are also safe from contracting shingles because they are young. |
What disease does the human herpesvirus-1 cause? |
cold sores or fever blisters |
Which of the following are symptoms of influenza infection? |
-muscle pain -headache -fever |
Drag each one of the labels onto the figure to identify the function of each structure. |
LEFT SIDE TOP TO BOTTOM: -assists the virus in exiting the cell after reproduction -protects the viral nucleic acid -recognizes and attaches to host cells -contains antigenic determinants RIGHT SIDE: -contains the viral genetic information |
Arrange the following statements in the order that best describes the sequence of events involved in the replication of influenza. |
1. hemagglutinin spikes attach to host cells 2. influenza enters the host cell 3. nucleic acid enters the host cytoplasm 4. influenza proteins are synthesized 5. influenza nucleic acid is packaged in a capsid 6. influenza particles bud from the cell, releasing the virus into the surrounding environment |
Which of the following statements regarding antigenic shift are true? |
-little immunity to virus strains resulting from antigenic shift exists in the population. -viral strains resulting from antigenic shift contain RNA segments from different species. -antigenic shift results in a major change in the genetic composition of the virus |
Predict which of the following are reasonable outcomes of the cytokine storm during the 1918 flu pandemic. |
-increased fluid in the lungs and labored breathing -an excessive inflammatory response leading to extensive tissue damage |
What are some of the current challenges to production of the influenza vaccine? |
-in order to yield a vaccine, the virus must be produced in eggs -the virus undergoes antigenic changes on a regular basis |
Predict which of the following would be outcomes of treatment with Tamiflu. |
-an increase in the ability of the immune system to combat the infection -overall decrease in the replication rate of influenza -a decrease in the release of viral particles from the cell |
In which stage is the viral DNA introduced into the cell? |
penetration |
In which stage does formation of mature viruses occur? |
Assembly |
The host DNA is usually degraded during which stage? |
Biosynthesis |
What would be the fate of a lytic bacteriophage if the host cell died prior to the assembly stage? |
The virus would not be able to infect new hosts |