BIOL 2051 Chapter : Chapter 6
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 making viral proteins: capsid, genome replication proteins. Viroids and prions: viroids, rna without capsid (viruses without capsids) Virus structure capsids: capsid- protein coat surrounding nucleic acid, capsid proteins are arranged to give virion symmetry. Includes genes encoding viral proteins: capsid, envelope 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 helical or icosahedral or complex or regular, envelope. Presence or absence of host derived envelope: size of virus particles. Related viruses infect same or related hosts: host range. Baltimore virus classification based on genome structure- see figure 6. 14: group i. Uses its own or host dna polymerase for replication. Herpesvirus group - cold sores, venereal disease, chicken pox.
