BIOL 2051 Lecture Notes - Lecture 6: Lytic Cycle, Intracellular Parasite, Veterinary Virology
Document Summary
Obligate intracellular parasite made of nucleic acid surrounded by a protein coat. Viral genomes contain: information for taking over host cell, information for making viral proteins. Capsid proteins are arranged to give virion symmetry: icosahedral capsids. Long tube of protein, with genome inside. Tube made up of 100"s of identical protein subunits. Tube length reflects size of viral genome: complex capsids. Many bacteriophages (viruses that infect bacteria: asymmetrical (irregular) shapes. Envelope- lipid bilayer around capsid of some viruses. Allows fusion to host cell or organelle membrane: only occurs if host cell not covered by cell wall. Envelope lipids come from host: not encoded by viral genome. Proteins embedded in envelope may be encoded by virus: coats viral capsid as virus leaves cell or organelle. Includes genes encoding viral proteins: capsid, envelope proteins if virus is enveloped, any polymerase not found in host cell. Bacteriophage life cycles: attachment to host cell receptor proteins, bacterial cell receptors normally used for bacterial purposes.
