BIOL 2051 Chapter : Chap 6
Document Summary
Virus structure capsids: capsid- protein coat surrounding nucleic acid, capsid proteins are arranged to give virion symmetry. Icosahedral capsids (ex: poliovirus, herpes virus: roughly spherical, 20 equilateral triangles or faces, filamentous/ helical capsids [ex: m13, ebola] Virus structure genome: dna or rna [prokaryotes and eukaryotes are always dna; viruses can be either] Includes genes encoding viral proteins capsid: envelope proteins if virus is enveloped, any polymerase (for replication) not found in host cell. International committee on taxonomy of viruses classification system based on: genome composition. Whole or segmented; whole nucleic acids or segmented nucleic acids. Classified by baltimore method: capsid symmetry, envelope. Presence or absence of host derived envelope: size of virus particle. Related viruses are similar in size; pox viruses are large and asymmetrical. Related viruses infect same or related hosts. Viruses are usually very specific; influenza virus cannot infect e. coli but can infect humans,bird: host range. Baltimore virus classification based on genome structure: group i.
