NEET BIOLOGY

Detailed explanation-1: -Many viruses have either DNA or RNA as the genetic element and the nucleic acid with single or double strands. The whole infectious virus, called as virion has nucleic acid and an outer shell of proteins. The simplest virus includes DNA or RNA for encoding four proteins and the most complex encodes 100-200 proteins.

Detailed explanation-2: -Virus classification is based mainly on characteristics of the viral particles, including the capsid shape, the type of nucleic acid (DNA or RNA, double stranded (ds) or single stranded (ss)) within the capsid, the proces s of replication, their host organisms, or the type of disease they cause.

Detailed explanation-3: -Viruses are classified on the basis of morphology, chemical composition, and mode of replication.

Detailed explanation-4: -Viruses can also be classified by the design of their capsids (Table 2 and Figure 2). Capsids are classified as naked icosahedral, enveloped icosahedral, enveloped helical, naked helical, and complex.