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37 Cards in this Set
- Front
- Back
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What are the three main properties of viruses? |
1. small size 2. obligate, intracellular parasites 3. Composed of nucleic acids and proteins |
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What 2 types of genomes that viruses can have? |
DNA & RNA |
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What are the six DNA viruses? |
PPPHHA Parvo, papova, pox, hepadna, herpes, and adeno |
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Can viruses replicate without a host cell? |
NO |
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What 4 things are viral classification based on? |
1. Physical/Chemical properties 2. Virus size & morphology 3. Genome structure 4. Replication Strategies |
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What are the 2 basic shapes of viruses? |
1. Polyhedral 2. Helical |
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How are enveloped viruses described, transmitted, and targeted by antivirals? |
1. liable 2. direct contact/person-to-person 3. envelope proteins |
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Which virus is neither helical or polyhedral? |
Pox virus |
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What are defined as viruses that infect bacteria? |
Bacteriophages |
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Define the differences between the lytic cycle and lysogenic cycle. |
Lytic: cell is destroyed Lysogenic: latent period, typically when environmental conditions are not favorable. |
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What are the steps of viral replication? |
1. Adsorption/Attachment 2. Penetration 3. Uncoating 4. Biosynthesis 5. Maturation 6. Assembly 7. Release |
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What are some bad effects phages can have? |
Ruin yogurt & milk products |
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What are some benefits of phages? |
Phages can prevent biofilms and could potentially be used to fight antibiotic resistant bacteria |
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Central dogma for eukaryotic DNA replication? |
DNA --> RNA --> protein |
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How is viral replication studied? |
One step growth curves |
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Which portion of the one step growth curve represents the time it takes the virus to complete one replication cycle? |
Eclipse |
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Which portion of the one step growth curve indicates the time it takes to assemble and release infectious virus from the host cell? |
Maturation |
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How do enveloped viruses penetrate host cells? |
Receptor fusion or endocytosis |
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How do naked viruses accomplish penetration of host cells? |
Clathrin-coated pits |
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Where do DNA viruses replicate? |
Nucleus (except Pox virus) |
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What are the 3 viral gene expression phages of DNA viruses? |
1. Immediate Early Genes: regulatory genes 2. Early Genes: involved in DNA replication 3. Late Genes: encode for structural proteins |
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Where do RNA viruses replicate? |
In the cytoplasm |
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Why are RNA viruses more prone to mutation? |
The have no proofreading ability |
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What is the main difference between positive polarity RNA viruses and negative polarity RNA viruses? |
Positive has a genome that can directly serve as mRNA. Negative does not. |
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How do negative strand RNA viruses replicate? |
It has its own transcriptase in its capsid that then makes the mRNA. Makes a + strand to make more - strands. |
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How HIV unique in the way it replicates? |
Uses DNA as an intermediate |
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What are the 5 possible outcomes of viral infection? |
1. Abortive Infection 2. Lytic Infection 3. Persistent Infection 4. Latent Infection 5. Transformation |
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What route do most bacteria enter the body? |
Respiratory tract |
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What are the mechanisms through which viruses spread? |
1. Localized infection 2. Systemic infection |
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What are the 4 types of Virus Diseases? |
1. acute infection 2. acute infection followed by persistent/latent infection 3. chronic infection w/ continuous virus shedding 4. Slow infection |
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What are the 4 steps of disease progression? |
1. Incubation 2. Prodromal Period 3. Period of Illness 4. Convalescence |
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What are the 5 main methods for laboratory diagnosis of viral diseases? |
1. Microscopy 2. cell culture 3. viral antigen detection 4. nucleic acid detection 5. antibody dectection |
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Which diagnostic method is fast, allows for visualization of infected cells, is useful for non-culturable cells but cannot directly diagnose the disease & can involve expensive equipment? |
Microscopy |
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Which diagnostic method confirms viral infection in a patient specimen that can be grown and isolated in a lab, but is slow, requires technical help, and may not be able to isolate some viruses? |
Cell Culture |
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Which diagnostic method is rapid, sensitive, and specific, but can be difficult to interpret, gives false positives, and can be disadvantageous due to its specificity? |
Detection of Viral Antigens |
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Which diagnostic method is simple, extremely sensitive, and specific but requires knowledge of the virus and can be oversensitive? |
Detection of Nucleic Acids |
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Which diagnostic method confirms present infection (IgM) or past infection (IgG) but can take up to 10 days for the patient to produce a response for this test? |
Detection of Viral Antibodies |
