What type of nucleic acid can viruses contain?

Viruses are unique entities that can contain either DNA or RNA as their nucleic acid, but they never have both simultaneously. This characteristic is essential for their classification and understanding of their biology.

For instance, DNA viruses possess genetic information in the form of deoxyribonucleic acid, while RNA viruses use ribonucleic acid. This distinction influences not only the virus's replication mechanisms but also the types of diseases they may cause and the strategies used for treatment and vaccine development.

The presence of proteins in viruses, while critical for their structure and function (as viruses are composed of a protein coat that surrounds their nucleic acid), does not relate to the type of nucleic acid they contain. Therefore, stating that viruses contain only proteins would be inaccurate and misleading.

Overall, understanding that viruses can have either DNA or RNA helps to appreciate their diversity and the various approaches needed for viral detection and treatment.