A. DNA viruses.
1. Contain double-stranded DNA (except for parvoviruses).
2. Are naked viruses (except for herpesviruses, poxviruses, and hepadnaviruses).
3. Have icosahedral capsids and replicate in the nucleus (except for poxviruses).
B. RNA viruses.
1. Contain single-stranded RNA (except for reoviruses, rotaviruses, coltiviruses, orthoreoviruses, and orbiviruses).
2. Are enveloped (except for caliciviruses, picornaviruses, and reoviruses).
3. Have helical capsids (except for picornaviruses, reoviruses, and togaviruses).
4. Are classified positive, negative, or ambisense, depending on the ability of virion RNA to act as messenger RNA (mRNA).
5. Replicate in the cytoplasm (except for orthomyxoviruses and retroviruses, which have both a cytoplasmic and a nuclear phase).
Source >>> BRS