Lecture 4: Viruses and Other Acellular Infectious Agents Flashcards
Bacterial viruses are called?
Bacteriophages
Do archaeal have few or many viruses?
Few Archaeal Viruses
True or False:
Most virions are eukarotic viruses.
True - plants, animals, protists, and fungi.
What are virions classified into families based of?
- genome structure
- life cycle
- morphology
- genetic relatedness
What are viruses classified by?
- Morphology
- helical viruses
- polyhedral viruses
- enveloped viruses
- complex viruses
What are 2 examples of a helical virus?
- Rabies
- Ebola hemorrhagic fever
What are 2 examples of a polyhedral virus?
- Adenovirus
- Poliovirus
What is the largest animal virus?
poxviruses
What do viruses attach to?
Cell Membrane
How do viruses penetrate/enter the host cell?
endocytosis or fusion
How are animal viruses released from the host cell?
By budding (enveloped viruses) or rupture.
In the influenza virus, what is hemagglutinin required for?
In viral attachment to the host cell.
What are the steps in animal virus multiplication?
- Attachment to host cell
- Penetration/Entry
- Uncoating of genome
- Biosynthesis
- Maturation/Assembly
- Release
True or False:
Nonenveloped viruses lyse the host cell to escape.
True
What is the special features of biosynthesis for ssDNA?
- Cellular enzyme transcribes viral DNA in nucleus.
- Virus Family -> parvoviridae
What is the special features of biosynthesis for dsDNA?
- Cellular enzyme transcribes viral DNA in nucleus for herpesviridae and papovaviridae.
- Viral enzyme transcries viral DNA in virion, in cytoplasm for poxviridae.
- Virus Family ->
- herpesviridae
- papovaviridae
- poxviridae
What is the special features of biosynthesis for reverse transcriptase DNA?
- Cellular enzyme transcribes viral DNA in nucleus; reverse transcriptase copies mRNA to make viral DNA.
- Virus Family -> hepadnaviridae
What is the special features of biosynthesis for + strand RNA?
- Viral RNA functions as a template for synthesis of RNA polymerase which copies – strand RNA to make mRNA in cytoplasm.
- Virus Family ->
- picornaviridae
- togaviridae
What is the special features of biosynthesis for - strand RNA?
- Viral enzyme copies viral RNA to make mRNA in cytoplasm.
- Virus Family -> rhabdoviridae
What is the special features of biosynthesis for dsRNA?
- Viral enzyme copies – strand RNA to make mRNA in cytoplasm.
- Virus Family -> reoviridae
What is the special features of biosynthesis for reverse transcriptase RNA?
- Viral enzyme copies viral RNA to make DNA in cytoplasm; DNA moves to nucleus.
- Virus Family -> retroviridae
