BIOL 2051 : Exam 2 Notes
Document Summary
General properties of viruses (virions: obligate intracellular parasite made of nucleic acid surrounded by a protein coat, only replicate inside host. No nucleus, organelles, cytoplasm: viral genomes contain information for taking over the host cell information for making viral proteins, capsid, genome replication proteins. Viroids and prions: viroids, prions, rna without capsid (viruses without capsids) Infect plants: protein-only infectious agent, bse (mad cow), scrapie (sheep), creutzfeld-jakob, kuru (humans), chronic wasting disease (deer, elk, defective protein causes normal protein to take an abnormal shape, loses normal function. Virus structure capsids: capsid- protein coat surrounding nucleic acid, capsid proteins are arranged to give virion symmetry. Includes genes encoding viral proteins: capsid, enveloped proteins if virus is enveloped, any polymerase not found in host cell. International committee on taxonomy of viruses classification system based on: genome composition. Classified by baltimore method: capsid symmetry, envelope helical or icosahedral. Presence or absence of host derived envelope: size of virus particle.
