Chapter 10 viruses
infectious agents that are too small to be seen with a light microscope and that are not cells
are a nucleic acid core, and a surrounding protein coat
surrounding lipid bilayer membrane
Complete virus particle, including the envelope, if it has one
protein subunit that each capsid is composed of
usually has bilayer membrane outside of capsid
comprises the viral genome together with the capsi
extend from viral envelope (some have some do not)
spectrum of hosts that a virus can infect
specific kinds of cells a virus can infect
+ strand (RNA)
- strand (RNA)
converted to +RNA or DNA first
Picornaviridae (RNA virus)
Togaviridae (RNA virus)
Flaviviridae (RNA virus)
Retroviridae (RNA Virus)
Paramyxoviridae (RNA Virus)
mumps, measles, viral pneumonia
Rhabdoviridae (RNA virus)
Orthomyxoviridae (RNA virus)
Influenza A, B
A cross species
Filoviridae (RNA virus)
Bunyaviridae (RNA virus)
Arenaviridae (RNA virus)
Reoviridae (RNA virus)
Adenoviridae (DNA virus)
More than 80 types
Herpesviridae (DNA Virus)
Simplex:oral and genital
Cytomegalovirus: birth defects
Lymphocryptovirus : Mono, Burkittâ€™s lymphoma
Varicellovirus:chicken pox, shingles
Poxviridae (DNA virus)
Papovaviridae (DNA Virus)
Hepadnaviridae (DNA virus)
Parvoviridae (DNA virus)
the attachment of viruses to host cells.
the entry of virions (or their genome) into host cells.
the synthesis of new nucleic acid molecules, capsid proteins, and other viral components within host cells while using the metabolic machinery of those cells.
the assembly of newly synthesized viral components into complete virions
the departure of new virions from host cells. Release generally, but not always, kills (lyses) host cells
Carries the genetic information necessary for replication of new phage particles
Tail sheath Function
Retracts so that the genome can move from the head into the host cell’s cytoplasm
Plate and Tail Fibers Function
Attach phage to specific receptor sites on the cell wall of a susceptible host bacterium
Primary cell cultures
come directly from the animal and are not subcultured. The younger the source animal, the longer the cells will survive in culture
A continuous cell line culture
consists of cells that will reproduce for an extended number of generations
reproduction “revolves around” a helper virus.
an infectious RNA particle smaller than a virus
1.resistant to inactivation by heating, will inactivate viruses.
2. Prion infection is not sensitive to radiation treatment that damages virus genomes.
3. not destroyed by enzymes that digest DNA or RNA.
4. Prions are sensitive to protein denaturing agents, such as phenol and urea.
5. Prions have direct pairing of amino acids.
viral genes that cause host cells to divide uncontrollably
normal genes that, when under the control of a virus, act as oncogenes, causing uncontrolled cell division.
DNA tumor viruses
contain viral genes whose protein products disrupt the activities of normal host cell proteins that control cell division
RNA tumor viruses
contain viral genes used for neoplastic transformation and viral replication