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21 Cards in this Set
- Front
- Back
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Virus |
Genetic element containing RNA/DNA that replicates in cells, surrounded by a capsid, and sometimes and envelope, narrow host range |
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Viral genome |
DNA or RNA Single Stranded or Double Stranded |
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Baltimore classification system |
genome of virus |
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Bacteriophage have ____ genome |
dsDNA |
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Viruses are large or small? |
Small, in fact to small to be able to replicate on their own |
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Importance of bacteriophage interactions |
Control microbial population size Influence phenotype of host prokaryote Used in molecular bio |
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Quantification of bacteriophage using a plaque assay |
1. Add small amount of bacteria to phage sample 2. Mix with molten agar 3. Poor and incubate 4. Plaque assay forms |
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Virus replication aka |
Phage Lytic Cycle |
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Steps of phage lytic cycle |
1. Attachment- viral protein to receptor 2. Penetration 3. Gene expression and protein production 4. Viral particle self assembles 5. Phage particles released and cell lyses |
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Permissive vs resistant |
Permissive - allow virus to multiply Resistant - no surface receptor or restriction endonucleases destroy phage DNA |
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T4 |
dsDNA bacteriophage Infects Ecoli Very fast cycle |
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Bacteriophage entry |
1. Tail fiber attach to receptors 2. Conformation change, tail contacts cell wall 3. Inner core tube extends into wall 4. Contacts plasma membrane, DNA is transferred through a pore in lipid bilayer |
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Temperate bacteriophage eg |
lambda phage |
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Lysis vs Lysogeny |
Replication and release or integration of viral DNA into host genome |
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Lysogens |
Bacterial cells carrying and integrated phage genome (prophage) passed from G1 --> next Can be induced to create a mature virus and lyse |
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Dx174 |
ssDNA first DNA to be sequenced |
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Transduction |
Transfer of host genes from one cell to anouther by a virus |
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Generalized Transduction |
Host bacterial gene accidentally packaged into a lytic phage |
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Specialized Transduciton |
Host bacterial gene integrates into lysogenic phage |
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lysogeny importance |
-Most bacteria isolated from nature are lysogens -Integrated viral genes can attack disease causing bacteria |
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Virus interaction importance |
-Viruses are the most abundant entity in aquatic ecosystems-Influence nutrient cycling, bacterial and algal diversity, and gene transfer |
