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25 Cards in this Set
- Front
- Back
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Host range |
The suitable cells for for a particular virus are referred to as it's host range |
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Tissue trophism |
Targeting only a specific set of cells |
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Virions |
When they are outside the cell and are metabolically inert |
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Structures |
-nearly all form a protein sheath or capsid around there nucleic acid core. - the capsid is composed of one to a few different protein molecules repeated many times called capsomeres. - many animal viruses have an envelope around the capsid that is rich in proteins lipids and glycoprotein molecules |
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Shape |
Helical - Rodlike or threadlike appearence Icosahedral- 20 equilateral facets
Binal- Much more complex
Polymorphic- No distinct symmetry
Vary greatly in size- Larger sized viruses tend to have a very short life cycle between entry of viral particles and release into newly formed virions |
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Positive strand viruses |
If the genome has the same base sequence as the mRNA used to produce viral proteins then the genomic RNA can serve as the mRNA. |
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Negative strand virus |
If the genome is not complementary to the viral mRNA. |
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Bacteriophage |
Viruses that infect bacteria |
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The Lytic cycle |
The lyctic cycle Attachment- When the virus contacts the cell and becomes specifically bound to the cell Penetration- Results in the release of the virus into the host Synthesis- The virus takes over the cells replication and protein synthesis in order to synthesize viral components Assembly- Where these components are assembled to produce fully mature virus particles
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Lysogenic |
Viruses that integrate their nucleic acid into the genome of the infected host cell |
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Indication |
The switch from a lysogenic prophage to a lyctic cycle |
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Prophage |
The DNA segment that is integrated into host cells genome. The resulting cell is a lysogen |
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The lysogenic cycle |
1. Virus attaches to cell and injects DNA 2. Viral DNA forms a circle 3. Viral DNA attaches to host chromosome, and becomes inactive prophage. 4. Host cell reproduce normally and makes more viral DNA 5. Prophage DNA breaks loose from host chromosome. |
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Phage conversion |
When the phenotype or characteristic of the lysogenic baterium is altered by the phrophage |
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When was Aids first reported |
1981 in america |
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Opportunistic diseases |
Diseases a healthy person could fight off but a person who has aids can die of. |
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HIV testing |
Test for the presence of antibodies against HIV |
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The HIV infection cycle |
1. Attachment-the gp120 glycoprotein on the surface of HIV attaches to CD4 and one of two corereceptors on the surface of a CD4 cell 2. The viral contents enter the cell by endocytocis 3. - 4. The double stranded DNA is then incorporated into the host cells DNA by a viral enzyme 5. Transcription of the DNA results in the production of RNA- can serve as the genome for new viruses. 6. Complete HIV particles are assembled and HIV buds out of the cell. As the disease |
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Aids treatment |
• Viral entry, genome replication (reverse transcriptase), integration of viral DNA and maturation of HIV proteins |
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When did the influenza pandemic occur |
1918-1919 |
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Structure of the flu virus |
A rod spudded with two kinds of proteins. Subtypes differ in their protein spikes |
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Hemagglutinin |
A protein that aids the virus in gaining access to the cell interior |
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Neuraminidase |
A protein spike that helps the daughter viruses break free of the host cell once virus replication has been completed |
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Emerging organisms |
Viruses that originate in one organism and then pass to another and cause disease |
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prophage |
the genetic material of a bacteriophage, incorporated into the genome of a bacterium and able to produce phages if specifically activated. |
