Term
| What shape types of of viruses infect humans? |
|
Definition
-Cubical (icosahedron), enveloped and non-enveloped
-Helical, non-enveloped only
-**No helical enveloped viruses infect humans |
|
|
Term
| What is in the envelope? Where does it come from? What will the infected cell look like? |
|
Definition
-The envelope is derived from the host cell's pm, or sometimes the nuclear envelope or ER
-It contains viral glycoproteins (have transmem domain)
-The infected cell will always display these in enveloped viral infection
-*Will not display them if infected with naked virus |
|
|
Term
| What is the difference between enveloped and naked? |
|
Definition
-Enveloped are not stable in the environment and need aerosols for stability in transmission (sneeze, body fluids etc.), and are inactivated by solvents and digestive juices
-Naked, on the other hand, are stable in harsh environments (stomach, air, etc.)
-All GI viruses will therefore be naked
-Dissolving the envelope with organic solvents be used to test whether a virus is enveloped or not |
|
|
Term
|
Definition
| -It is naked; that's why it could live on the green onions in chi-chi's |
|
|
Term
| Where does the viruses go in the cell? What are the exceptions? Where do they translate mRNA? |
|
Definition
-RNA viruses pretty much stay in the cytoplasm, but DNA viruses go to the nucleus
-**Influenza and retroviruses are RNA viruses that make use of the nucleus
-Poxviruses are DNA viruses that remain in the cytoplasm
-They all translate in the cytoplasm (because we translate in the cytoplasm and they rely on our machinery) |
|
|
Term
| Are DNA viruses double or single DNA stranded? What is the exception? |
|
Definition
-Almost all are *dsDNA viruses
-The exception is **parvovirus |
|
|
Term
| What makes the viral mRNA from viral DNA? Example? Exception? |
|
Definition
-DNA-dependent RNA pol II* (from host*) (DdRp)
-Herpes is an example
-Retrovirus also use the cells RNA pol II (HIV)
-**Poxvirus uses its own proteins! (it doesn't enter nucleus) |
|
|
Term
| What makes the viral mRNA from RNA? Give an example? |
|
Definition
-RNA-dependent RNA polymerase (viral** because we don't make one)
-MMR |
|
|
Term
What kinds of viruses are the following (ignoring ss ds) and what is their genome pathway?;
Herpes
MMR
HIV
Hep B |
|
Definition
Herpes; DNA virus
-DNA>DNA>mRNA>protein
MMR; RNA virus
-RNA>RNA>mRNA>protein
-notice that the two simple types (non-retro) do a simple replication step, and then go to mRNA and protein
HIV; Retrovirus (RNA)
-RNA>DNA>mRNA>protein
-The replication step here isn't shown
Hep B; Pararetrovirus (DNA)
-DNA>mRNA>DNA & protein
-For some odd reason, DdDp is not used to make extra genome copies (from mRNA instead)
-Note that both HepB and HIV have RdDp (reverse transcriptase) |
|
|
Term
| What does it mean to have a segmented genome? |
|
Definition
-Just multiple parts to it (like we have multiple chromosomes)
-Keep in mind this is different than saying it's diploid (retroviruses are ss diploid) |
|
|
Term
|
Definition
-RNA that can be coded from (mRNA is +)
-Viruses can be *positive sense viruses (+RNA)
-The advantage is that they can immediately code for proteins (like *RdRp) |
|
|
Term
| What would be the process for a +RNA virus? Where does the RdRp come from? |
|
Definition
-Would do translation right off the bat (to make **RdRp)
-Next it would do replication to make an *antigenome
-From that, a bunch of mRNA identical to the original genome would be made
-FInally we get more translation (but in greater amounts)
-The RdRp is not held in the capsid (like it would have to be for -RNA viruses) |
|
|
Term
| What is "infectious RNA"? |
|
Definition
-When pure RNA can cause infection
-Would have to be +RNA (can code immediately with no need for added viral proteins) |
|
|
Term
|
Definition
-Open reading frame
-Requires start and stop |
|
|
Term
| What would be the process for -RNA? |
|
Definition
-Virus associated RdRp would make both mRNA and a *+sense genome
-The mRNA would be used for protein and the +sense antigenome would be used to make for -RNA (genome)
-Keep in mind, -RNA viruses need RdRp in the capsid with it, so it is **not infection RNA |
|
|
Term
| What is the first step after entry for + and -RNA? |
|
Definition
-The +RNA goes straight to protein (namely RdRp, which it needs to progress, but didn't need in the capsid)
-The -RNA goes to transcription (already has RdRp, but needs sense genetic info to make protein) |
|
|
Term
| Do dsRNA viruses have RdRp with them? What is a special example of dsRNA viruses that has one + and one - strand? |
|
Definition
-Yes
-Could have a +sense coding for it in there, but I guess they don't
-We call that an ambisense RNA virus; still carries RdRp
-Arenaviruses are ambisense |
|
|
Term
| What viruses have diploid RNA? What do they have with them? What can they leave in the host? |
|
Definition
-Retroviruses
-Carry reverse transcriptase in the particle
-A *provirus is a viral integrated genome into host cell |
|
|
Term
| What kind of virus is the Pox virus and what is in its capsid? |
|
Definition
-It is a DNA virus that is weird because it replicates in the cytoplasm instead of the nucleus
-It, therefore, must carry both a DNA pol and RNA pol |
|
|
Term
What are the cellular receptors for the following viruses?;
HIV
Influenza
Rhinovirus
EBV
Rabies |
|
Definition
HIV; CD4 (Th cells)
Influenza; Sialic acid
Rhinovirus; ICAM-1
EBV; CR2 (C3d receptor in compliment)
Rabies (ACh receptor) |
|
|
Term
| How does fusion work in neutral and acidic pH for enveloped viruses? |
|
Definition
-At neutral, it fuses and the viral envelop becomes part of the host pm
-At acidic we see **viropexis, where an endosome forms, giving the virus a double membrane |
|
|
Term
| What is the difference between antigenic shift and genetic drift? |
|
Definition
-Genetic drift is the natural changing of the pathogen
-Antigenic shift is the change depending on recombination from two species |
|
|
