Flashcards
Lectures 23+24 (viruses)
Cards in this deck (30)
- 1What genetic material does poliovirus have?(+) strand RNA
- 2What is the RNA in (+) strand RNA viruses involved in?Acts as mRNA and encodes the viral genome
- 3What is the RNA in (-) strand RNA viruses involved in?Encodes the genome but can't directly act as the mRNA
- 4What kind of virus includes rabies?Rhabdoviruses
- 5Are rhabdoviruses enveloped?Yes
- 6What viral enzyme is essential for RNA transcription in rhabdoviruses?RNA replicase
- 7What are the 2 classes of RNA transcribed in rhabdoviruses?(+) strand RNA, required for transcription of (-) strand genome using viral RNA polymerase
mRNAs for translation of proteins - 8What are the characteristics of the influenza genome?Segmented ssRNA genome
- 9How many molecules of RNA does influenza A have?8
- 10What viral enzymes does influenza have?RNA replicase, RNA endonuclease
- 11What does RNA nuclease do?Cuts a primer from the hosts capped mRNA precursors
- 12Where does influenza viral nucleic acid replicate?Nucleus
- 13Where are influenza mRNAs translated?Cytoplasm
- 14What is antigenic drift?Arises from mutations in the genes for surface proteins
- 15What is antigenic shift?When portions of the RNA genome from two genetically distinct strains are reassorted, leads to a significantly different combination of surface proteins. Origin of pandemics and epidemics
- 16Where in eukaryotic cells do DNA viruses replicate?All replicate in the nucleus except for pox virus
- 17What are some characteristics of polyomaviruses?Some induce tumours, no viral encoded enzymes, genome is one dsDNA circle
- 18How is SV40 replication initiated?- Single RNA primary transcript is made by the cellular RNA polymerase
- This is processed into 2 capped mRNAs
- Introns removed - 19How is SV40 genome synthesis carried out?- T antigen binds to the origin of replication to initiate genome syntheisis
- The DNA is replicated in a bidirectional fashion using host DNA polymerase - 20What is the difference between permissive and non-permissive cells?Permissive allow normal viral replication and lysis, non-permissive allow DNA integration (such cells can undergo transformation into tumour cells
- 21What is the difference between retroviruses and hepadnaviruses?Both use a reverse transcriptase, retrovirus have RNA genome and hepadnavirus a DNA genome
- 22How are retrovirus genomes replicated?The RNA genome is replicated through a DNA intermediate, which requires a reverse transcriptase and a primer (which is a tRNA packaged into the virus from a previous host)
- 23What does the retroviral genome consist of?2 identical ssRNA strands, gag region encodes structural proteins, env region encodes envelope proteins that sit in the membrane, pol encodes the reverse transcriptase and an integrase
- 24How is retroviral gene expression initiatated?Activation of promoters in LTR
- 25What are the characteristics of hepadnavirus genomes?DNA genome, very small, overlapping genes, only part of the genome is dsDNA
- 26How does hepadnavirus replicate?Involves transcription by a host RNA polymerase in the nucleus. A single genome length mRNA is made as an intermediate. The reverse transcriptase then copies this into DNA.
- 27How is the DNA polymerase versatile?Has both DNA polymerase and reverse transcriptase activity. Also acts as a protein primer for one of the DNA strands
- 28Where do pox viruses replicate?Cytoplasm
- 29What are the characteristics of the pox virus genome?Linear dsDNA, two strands of the double helix are cross linked at their termini through phosphodiester bonds
- 30How is uncoating of pox virus carried out?Requires a viral protein that is synthesised in the cytoplasm after infection, which is transcribed by a viral encoded RNA polymerase
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- BSci Genetics Flashcards on Lectures 23+24 (viruses), created by Kayla Price on 01/06/2018.
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- Kayla Price
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