Download Virology study guide for mid

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Virology study guide for mid-exam
Part two
1. Virus infectious life cycle
Viruses can multiply only in active host cells, the replicate cycle of viruses
can be divided into number of stages:
•
•
•
•
•
Attachment Viruses attaches to cell membrane
Penetration By endocytosis or fusion
Uncoating
By viral or host enzymes
Biosynthesis Production of nucleic acid and proteins
Maturation Nucleic acid and capsid proteins
assemble
• Release
By budding (enveloped viruses) or rupture
‫على الطالب ان يعرف ترتيب هذت الخطوات وما فائدة كل خطوة وكيف تختلف الفيروسات بينها‬
‫واي خطوة يحتاج الفيروس الى الطاقة او االنزيمات حتى ينفذ العملية‬
1. Factors important for attachment: the virus particles present and
2. the availability of appropriate receptors molecules,
virus-cell interaction determines both the host range and tissue tropism of viral species
. Viruses can select a point where they can utilizethe wide range of host cell surface proteins
as receptors.
2. What’s mean by tissue tropism?
3. What’s are the ligand and receptor sites for HIV?
Steps of entrya. receptors-mediated endocytosis occur after virus attaches to
receptors and particular sites on the plasma membrane, this virus
receptors complex is taken in to the cell in specialized vesicles, then by
acidification within the vesicles
1. lead to degradation of viral structures
2. b. In enveloped viruses (Paramyxovirus, Retrovirus and Herpesvirus),
involves fusion of the viral envelop with the plasma membrane , this
allows release of the nucleocapsid directly into the host cells cytoplasm.
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3. c. Direct introduction or translocation of viral genomes into the cytoplasm
through channels in the plasma membrane e.g. non-enveloped
viruses(Picornavirus).
4. Uncoating means:- the process where by the viral genome is released in a
form suitable for transcription. Examples:
5. replication of DNA virus:Differences between dsDNA and ssDNA, also between SSRNA (+ or -).
What’s kind of enzymes they need?
Example of retrovirus and other viruses.
6. Comparison between biosynthesis of RNA and DNA viruses (Table).
7. Where does the Assembly of virus particle occurs? Do not forget the
examples.
8. What’s the difference between lytic and lysogenic bacteriophage cycles?
9. Specialized transduction?
10.
Compare between phage and animal virus multiplication? (Table)
11.
Differences between exocytosis and latency?
12.
Role of specific and non-specific recognition in virus lysis.
13.
What’ the effects of virus on the host?
14.
Pathogenesis?
15.
Requirement for successful infection.
16.
One virus example for rout of entry.
17.
Effect of virus infection at cellular level?
Cellular injury
Inclusion bodies
18.
What’s the inclusion bodies? Type. Example of viruses
19.
Latent infection: where? Name of viruses, character of growth?
20.
Difference between acute, chronic and latent virus infection.
21.
Congenital viruses?
22.
Examples of pathogenesis- the sequences; step by step, when virus
go to blood, antibodies, incubation period.
23.
Host response (all important to the end)
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24.
Do viruses produce toxins and can the body produce anti-toxins
against them?
25.
Antibody-mediated immunity
26.
Cell-mediated immunity (CMI)
27.
Active immunization
28.
Passive immunization
29.
Type of vaccines?
30.
Antiviral mode of action and virus example.
The end