Structure

= Structure  =



====The basic structure of a virus is a viral genome (containing the genetic material of the virus), a capsid (a protein shell for the genome made of subunits called capsomeres), and a viral envelope (covering the capsid; contains viral glycoproteins as well as material from the host cell's membrane). The four main structures of viruses are rod-shaped, polyhedral, bearing a viral envelope, and having a protein tail extending from the capsid (like in the classic phage). ====

====The Epstein-Barr virus's viral genome contains double-stranded DNA, making it a class I virus (see Classification). This genome is in the shape of a torus (linear and ring-shaped) when the virus is outside the cell. EBV belongs to the third category of viruses, having a viral envelope, although within the envelope its capsid is shaped like a polyhedral. EBV has a capsid shaped like a doughnut of 100-200 nanometers, as well as a nucleocapsid of icosahedral shape made of 162 capsomeres. As a herpesvirus, its envelope contains the host cell's nuclear membrane, not its cellular membrane. Its viral envelope is highly fragile. As its envelope is made of lipids, acids, detergents, and certain solvents can damage the envelope. If EBV's envelope is damaged, it cannot reproduce and thus is not infectious. EBV's tegument - the space between the capsid and the envelope - contains viral proteins and enzymes necessary for reproduction. ====



====//A picture from an electron microscope of the Epstien-Barr virus, as well the location of genes in its viral genome. See Replication, Reproduction, and Infection for more discussion of these genes. Source: Nature. //====