EVERYDAY SCIENCE

Detailed explanation-1: -Any particular virus contains only a single kind of nucleic acid. However, this may be DNA or RNA; indeed, the RNA viruses provide the only instance in nature in which RNA is the exclusive repository of genetic information.

Detailed explanation-2: -DNA and RNA viruses Unlike cells (e.g. bacteria, plant and animal cells), viruses contain either DNA or RNA, never both; the viral nucleic acid is either single or double stranded.

Detailed explanation-3: -Viruses are bundles of nucleic acid-DNA or RNA-that are enclosed by a protein shell known as a capsid. By some measures the most abundant life form on earth, 1 viruses lurk everywhere; experts estimate that they are 10 times more numerous than bacteria.

Detailed explanation-4: -The Basics of Viruses Unlike all other biological entities, some viruses, like poliovirus, have RNA genomes and some, like herpesvirus, have DNA genomes. Further, some viruses (like influenza virus) have single-stranded genomes, while others (like smallpox) have double-stranded genomes.

Detailed explanation-5: -Single-stranded (ss)DNA viruses are extremely widespread, infect diverse hosts from all three domains of life and include important pathogens. Most ssDNA viruses possess small genomes that replicate by the rolling-circle-like mechanism initiated by a distinct virus-encoded endonuclease.