Unit 6

• small enough to pass through fine-pored filter
• important b/c viruses are only active inside host cell
• ( OIP ) obligate intracellular parasite

• obligate intracellular parasite
• can not replicate unless inside a host and virus benefits from host's harm

• acellular
• unable to self-replicate
• contains no cytoplasm and call membrane

• protein coat
• -helical - hollow cylinder
• -polyhedral - icosohedral (20 triangular sides) --> capsomeres
• -complex - bacteriophage

the genome (nucleic acid) and the protein coat (capsid) of a virus

• contains lipid bilayer surrounding the virus capsid
• - component: from host membrane, lipids, and glycoproteins
• -properties: environmentally liable

• capsid proteins are exposed to the external environment
• capsid are responsible for attachment of the virus to the to-be infected cell

• 1. absorption - virus binds to host
• 2. penetrate - virus injects its genome into host
• 3. uncoating of envelop and capsid
• 4. synthesis of viral specific enzymes (early protein)
• 5. replication of viral genome using the host's cellular machinery
• 6. synthesis of structural protein (late protein)
• 7. assembly (maturation) -viral compnents assemble and viruses fully develop
• 8. release of intact virions - lysis and budding

a complete virus particle with its DNA/RNA core and protein as it exists outside the cll

gene that is mutated or expressed at high level and thus helps turn a normal cell into a tumor cell (proto-oncogen)

causes cancer

• cytopathic effect
• -degenerative changes in host cell due to infection

persistance of viral genome without viral replication

• detecting viruses in culture
• RBC will stick to infected cell surface

• detecting viruses in cultures
• protein binds to RBS and causes to agglutinate

• viral serology
• diagnosis of viral disease rely on a fourfold
• greater increase in antibody titer
• acute and convalescent --> compare titer

• manner in which the disease develop
• -source, transmission, penetrate, and what does it do the the host