diversity and biology of viruses Flashcards
What is the definition of a virus
Nucleoprotein complex which infects cells and uses the cells metabolic processes to replicate
What does it mean by viruses being metabolically inert
No metabolic activity outside host cell, must enter host cell to replicate
What is the typical size of a virus
10-400nm
What are structural components of viruses
Nucleocapsid
Lipid Envelope (+/-)
What is the genetic content in a virus
Nucleic acid
DNA or RNA
ss or ds
Linear, circular
Segmented
What are the functions of capsids
Protects NA (Nucleic acid)
Aids in transfer to/between hosts
What is the structure of a viral capsid
Protein coat
Capsomere arrangement (polyhedral, helical, complex)
What are capsomeres
Capsid subunits and protect Nucleic acid from degradation
What does the viral envelope surround
Surrounds capsid
What are sources of viral envelopes
Host plasma membrane
Nuclear membrane
Endoplasmic reticulum
(All cell derived)
What are the components of the viral envelope
Phospholipid
Proteins
Glycoproteins spikes
What are viruses which contain viral envelopes
Influenza
Rabies
Herpes
HIV
What are the properties of adenovirus
Leaner DS (double stand) DNA
Nonenveloped
Icosahedral
What are properties of herpesviridae
Icosahedral capsid
Enveloped
What are the properties of influenza virus
Helical nucleocapsid
Enveloped
What are properties of Ebola virus
Helical nucleocapsid
Enveloped
What are properties of poxvirus
Linear DS DNA
Enveloped
Complex (structure)
What is virus classification based on
Nucleic acid: DNA RNA
Envelope: YES NO
Symmetry: (Y)polyhedral (Y)helical
Icosahedral. Cylindrical
What suffix is used for viruses with similar structural, genomic and replication properties
Viridae e.g herpesviridae
What is the suffix of families subdivided into genera
Virus e.g herpes simplex virus
What are virus classification subtypes based on
Nucleotide sequence and antigenic reactivities e.g herpes simplex virus type 1, herpes simplex virus type 2
What does Baltimore classification describe
The relationship between viral genome and mRNA
What must viruses direct the synthesis of to produce proteins
Viruses must direct synthesis of mRNA to produce proteins
What types of tissue culture are viruses grown in
Human fibroblasts
Mouse 3T3 fibroblasts
Human HeLa epithelial cells
What can be used to quantify a virus
Plaque assay
How to calculate the virus quantification using plaque assay
Plaque count x 1/dilution = plaque forming units (PFU) per unit volume of inoculate
What method can be used for virus quantification without plaques
Cytopathic effect - cpe
What is the eclipse period
Time between virus infecting the cell, preparing for replication, production of genomes and proteins to assemble into a virus
