This preview shows pages 1–2. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.View Full Document
Unformatted text preview: Separated as fuction of their hosets At present , 1500 virus species described Animal viruses: Plaque formation Cytopathic effects the shape of the cell changed Bacteriophages-In broth cultures of young bacterial cells-In agar cultures on lawn of bacterial cells plague formation Plant viruses Plant tissue cultures Whole plants Structure of viruses Nucleocapsid core: either DNA or RNA Protein coat called capsid Four general morphological types -Icosahedron-Helical-Most complex ; large bacteriophage T2, T4, T6-Virus Replication-Virulent phage: 1. attachment ( adsorption) 2. penetration ( injection) 3. synthesis of nucleic acid and protein 4. assembly and packaging 5. release ( lysis) Burst size: number of virions released Virulent viruses Temperate viruses: state called lysogenry Virus Ecology Microorganism viruses persist...
View Full Document