Introduction to Virology Flashcards
What happened on May 14, 1796?
Edward Jenner used cowpox from milkmaid Sarrah Nemes to vaccinate 8 yr old James against smallpox
1970
David Baltimore and Howard Temin discover reverse transcriptase and retroviruses
1980
Smallpox eradicated
1983
HIV defined as the cause of AIDS
Arbovirus
Older term for AR-thropod BO-rne virus
- includes bunyaviridae, togaviridae, and orbiviruses and rhabdoviruses
- many viruses transmitted by insects are not considered arboviruses
Bacteriophage
Virus parasitizing bacteria
Capsid
Protein coat of a virus
Capsomere
Individual structural proteins that collectively make up the capsid
Defective interfering particle
Virus particle having a capsid, but an incomplete nucleic acid content, or an empty particle, which interferes with replication of complete particles
Envelope
Phospholipid covering derived from host cell membranes, either nuclear or cytoplasmic (plasma membrane or endoplasmic reticulum) present on some viruses
Icosahedron
Polyhedral shape composed of 12 vertices (corners) and 20 triangular faces
- icosahedron nucleocapsids are said to be of cubic symmetry
Nucleocapsid
Structural term denoting the combined nucleic acid and capsid
- may be helical or cubic in symmetry
Orphan virus
Virus isolated in the absence of disease
- virus not associated with a disease (can be species specific)
Peplomere
Glycoprotein subunit projecting from the envelope referred to as “spikes” that function in attachment to host cells
Prions
Unconventional agents of disease resulting in spongiform encephalopathies by proteins that cause protein folding anomalies
- ex: bovine spongiform encephalopathy, scrapie, kuru
- highly regulated
- intermediate hosts allow for zoonotic transmission
Translation
Process by which base sequences in mRNA produce specific amino acid sequences in a protein
Transcription
Process of forming mRNA from nucleic acid, not necessarily DNA
Virion
Individual viral particle
Viriods
Class of infectious agents, occurring in plants that are smaller than viruses and consist of short strands of RNA without a capsid
Virus
Complex molecular particle, capable of infecting cells and causing disease by redirecting host cellular synthetic machinery towards the synthesis of new infectious particles
- composed of nucleic acid (DNA or RNA, but not both), proteins, and sometimes lipids and carbs in the form of glycoproteins
What is the main driving force of evolution?
Viruses
All viruses are _______
Endogenous
Are functional viral proteins part of the viral structure?
No, just induce change in the host
What is the rate limiting step in protein transcription?
RNA
- half life is in microseconds
All viruses that carry RNA are _______
Negative sense
- if they are positive sense, then they are coded for by that virus
DNA viruses - replication enzymes
Are all DNA dependent, DNA polymerase
- herpes, adeno, papova, and parvo are coded for by the host cell. all others are coded for by the virus
RNA viruses - replication enzymes
Are mostly RNA dependent, RNA polymerase
- retro is RNA dependent, DNA polymerase (RT)
- bunya, orthomyxo, paramyxo, rhabdo, reo, retro, and arena are all carried by virus
What DNA virus replicates in the cytoplasm?
Poxvirus
What RNA viruses replicate in the nucleus?
Paramyxo and retroviruses
What viruses are more diverse, due to lack of proofreading steps?
RNA viruses
