PATHOLOGY

Detailed explanation-1: -The simplest virions consist of two basic components: nucleic acid (single-or double-stranded RNA or DNA) and a protein coat, the capsid, which functions as a shell to protect the viral genome from nucleases and which during infection attaches the virion to specific receptors exposed on the prospective host cell.

Detailed explanation-2: -DNA viruses are divided into three major categories: double-stranded (ds) DNA viruses (e.g., poxviruses), single-stranded (ss) DNA viruses (e.g., parvoviruses), and pararetroviruses (e.g., hepadnaviruses). Large DNA viruses (> 10 kb) have dsDNA, whereas small DNA viruses typically have circular ss or dsDNA.

Detailed explanation-3: -A capsid is the protein shell of a virus, enclosing its genetic material. It consists of several oligomeric (repeating) structural subunits made of protein called protomers. The observable 3-dimensional morphological subunits, which may or may not correspond to individual proteins, are called capsomeres.

Detailed explanation-4: -A virus is an infectious microbe consisting of a segment of nucleic acid (either DNA or RNA) surrounded by a protein coat. A virus cannot replicate alone; instead, it must infect cells and use components of the host cell to make copies of itself.