Virus Structure and Function Flashcards
Define the basic properties of viruses.
Not alive
Submicroscopic, obligate intracellular parasites
Directs synthesis in host cells
List the strategies viruses employ for survival.
Housing genetic data in capsids
Genome contains all the infor to initate and complete an infectious cycle
Establish a relationship with the host lethally or benignly
Describe two means of classifying viruses.
Classical system, where viruses are grouped according to their shared physical properties
Baltimore System- based on the central dogma of DNA->RNA->Protein (aka how they produce mRNA)
Describe the seven basic virus genomes
dsDNA, gapped circular dsDNA, ssDNA, dsRNA, ss+RNA, ss-RNA, ss+RNA w/ DNA intermediate
dsDNA
Transcription of the (-) DNA strand as a template, using host RNA polymerase
Can be nuclear (more dependent) or cytoplasmic (more independent)
Gapped Circular dsDNA
Transcription of the (-) DNA strand as a template, using host RNA polymerase
Uses viral encoded reverse transcriptase to copy genome from viral mRNAs
ssDNA
Transcription of the (-) DNA strand as a template, using host RNA polymerase
Nuclear replication, involving formation of dsDNA as template
dsRNA
Uses RNA dependent RNA polymerase
ss+RNA
Uses RNA dependent RNA polymerase
Can be translated directly by cellular ribosomes
Amplification mediated by RpRp
ss-RNA
Packes RpRp with the virus
ss+RNA w/ DNA intermediates
Retroviruses, changing their ssRNA to dsDNA using reverse transcriptase. They then integrate into host genome
Capsid Types
Icosahedral and Helical
Envelope
Lipid bilayers with viral glycoproteins
Do not necessarily kill the host
Eclipse period
Time between 0-12hours after viral absorption where no infectious virus is detectable inside or outside of the cell
Latent period
The time between initiation of infection and release of new virus particles
