WATCHAGOTTAKNOW_micro_E2

WATCHAGOTTAKNOW_micro_E2 - Viruses before theyre in a host...

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Viruses before they re in a host are a nucelocaspid = genome + capsid (protein coat). In order to be a virus (divide, live) they must have a live cell to multiply in. Capsid From host cell membrane or nuclear material Virion Completely assembled virus outside the host cell Viruses grow in t. culture medium with a cell that the viruses can infect. You will see two things if it successfully infects. 1. holes develop in the layer of cells (monolayer) # of holes in monolayer = # of viral particles/plaque forming units 2. focus formations (cells start growing on top of other cells, etc. because cells no longer maintain contact inhibition) DNA virus replication- 1. virus is brought into the cell 2. replication is w/in nucleus (dna virus). aka :viral DNA is inserted into the nucleus of the cell that s infected 3. the viral dna goes ahead and commands the production of capsid proteins and whatever other proteins it needs to live (replicate dna and make protein coat) 4. protein gets back into nucleus and virus is assembled 5. virus can be released from the cell and a. lyse the cell when they re released or b. don t lyse the cell RNA virus replication 1. u need to make a mirror image of RNA 2. use RNA polymerase (catalyzes RNA that is complimentary to viral RNA) which the virus carries. RNA Virus Example Retrovirus/Oncovirus {because it can cause cancer} (ex. HIV) 1. Carries reverse transcriptase ( RNA dependent DNA polymerase) makes double stranded DNA from RNA 2. Inserts RNA into T4 helper cell and that inserts the ds-DNA (made via RT) into nucleus of cell this DNA is now inside the host s csomes and that inserted DNA = the provirus (contains all info needed to make more retrovirii). 3. Because reverse transcriptase makes 4 errors/10,000 bases copied - 3000 different variants of HIV can exist in an infected person. This is why antibodies don t work the virus mutates due to transcription errors and the antibody is useless. 4. Constant drop in T4 helper cell which makes it a leukemic leukemia. MHC Class I Peptide presented on surface of cell destruction marker Cell must now be destroyed for two reasons:cell dies. On all nucleated cells. 1. u don t want dna to mix with random proteins 2. the whole cell must be destroyed to stop viral replication MHC Class II cell isn t destroyed T4 Helper Cells cytotoxic T cells B cells Activate B cells to create antibodies The FLU the flu itself doesn t kill people. it predisposes u to bacterial pneumonia which is what kills you. It hits the upper and lower respiratory tract and when it multiplies it lyses the cells 8 th cause of death in the US
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Vaccine killed cell/virus body makes small response attenuated/live virus body makes large response (more like a real infxn) Hep B vaccine a subunit vaccine. Add a segment of biral DNA to yeast plasmid and the yeast expresses only the viral protein coat (surface antigen HepA vaccine immunoglobulin.
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WATCHAGOTTAKNOW_micro_E2 - Viruses before theyre in a host...

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