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35 Cards in this Set
- Front
- Back
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what does it mean that a virus is ubiquitous?
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viruses are everywhere, disease causing agents
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are viruses normally species specific or are they general?
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species specific
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bacteria are known to have positive effects, is there anything good about viruses?
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HELL NO.
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are viruses typically fatal?
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no, then they have nowhere to live, but there are exceptions (rabies, AIDS)
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Viruses account for at least what % of all illness?
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50%
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are the majority of infections symptomatic or asymptomatic?
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asymptomatic
so we don't even know it was there! this means they are still contagious |
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What is an obligate intracellular parasite?
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has to be inside a host
very small no enzymes for energy production (again have to use what is inside the cell) no synthetic machinery (no ribosomes, mRNA, etc.) one type of genomic nucleic acid, DNA or RNA NOT LIVING |
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is an obligate intracellular parasite living?
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Not living: we call them Complex mobile genetic elements
can't self regulate |
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What is the chemical (genetic) makeup of an obligate intracellular parasite?
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DNA or RNA genome (ss or ds)
surrounding capsid composed of protein capsomeres naked, or surrounded by cell-derived lipid envelope |
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What are the 3 virus structures?
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Icosahedral
Helical Complex |
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small pox virus has what structure?
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complex
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what are 2 structures inside a complex virus
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nucleosome: where DNA is
lateral body: carry ribosomes |
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virus classification is based on what 2 things?
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nucleic acid characteristics
structural characteristics |
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what do viruses attach to? what do they have to do this?
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viruses attach to extracellular receptors (that internalize the virus)
the virus uses a viral attachment protein to bind to them, mimic the ligand, and get pulled in |
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attachment of a virus can determine/influence 3 things
what are they |
1 . Host/species range of virus (unique, or conserved receptor)
2. Cell/tissue tropism (receptor specificity) of virus 3. Recovery/Prevention (immunity, and esp. vaccine development. New antivirals: entry inhibitors) |
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there are 5 steps to virus replication, please give them in order
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1. attachment
2. penetration/uncoating 3.biosynthesis 4.maturation 5.release |
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during viral release what happens if it is enveloped? naked?
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enveloped: budding
naked: death of the cell/cell dissolution |
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Class VI viruses (such as HIV) are so devastating because?
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viral infection becomes part of the HOST DNA via reverse transcription
so you aren't just infected with a virus, it is part of your chromosomal makeup! so it can be expressed and constantly remake viral particals |
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how do viruses lead to cell destruction? 4
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– inhibition of host DNA,
inhibition of RNA and/or protein synthesis, immune-mediated tissue damage |
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describe transformation and what it can lead to
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virus infects a cell that likes to divide
this causes the cell to divide even more this leads to a tumor |
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discuss a latent or persistent virus
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infects the cell and then sits in a cell dormant
still has potential to be reactivated where it will make virus and cause disease again (cold-sores, herpes) |
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what causes general body ache when responding to virus?
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immune complexes depositing in the tissues, leading to muscle aches
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HIV uses what mechanism of immune evasion?
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Infection and destruction of immune cells
oh snap. |
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varicella-zoster virus evades the immune system how?
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Block MHC I, II presentation of viral antigens
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herpes simplex virus, West Nile virus evade the immune system how?
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Block production or activation of complement, cytokines, interferon
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Ebola virus, hepatitis C virus evade the immune system via what mechanism?
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Prevent proliferation of activated T-cells; stimulate production of null cells
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Answer: influenza and HIV are good examples of using this mechanism of immune evasion
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What is antigenic variation (mutation)
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What are 5 of the ways viruses are transmitted?
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person to person (sexual, contact, etc)
blood (transfusion, tattoos, etc) vector (animals, mosquitoes, flies) food, water (handlers, utensils, fecal oral) |
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Latency/Recurrence is a unique trait of what virus?
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herpes
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the adeno virus has what unique feature
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persistence
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why can't we give a vaccine for the common cold?
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substrain abundance
it just changes too often |
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papilloma virus and retro viruses are able to do what?
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alter cell cycle
they are oncogenic |
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See Negri bodies what are you thinking?
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RABIES
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Councilman bodies are seen in what?
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viral hepatitis
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if you see Koplick's spots what are you thinking?
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measles
they are white spots in the mouth |
