Virus replication is a complex and highly orchestrated process that varies among different types of viruses. Broadly categorized as either DNA or RNA viruses, they employ diverse strategies to replicate within host cells. In general, the replication cycle involves attachment and entry into the host cell, genome release, replication of viral genetic material, transcription and translation of viral proteins, assembly of new viral particles, and their release to infect other cells. DNA viruses typically replicate in the host cell nucleus, where they utilize cellular machinery for transcription and translation. RNA viruses, on the other hand, may replicate in the cytoplasm, using viral enzymes to replicate their genetic material. Positive-sense RNA viruses can directly serve as messenger RNA for protein synthesis, while negative-sense RNA viruses must first synthesize a complementary RNA strand. Retroviruses, like HIV, convert their RNA genome into DNA using the enzyme reverse transcriptase.