Final answer:
Retrovirus particles contain the enzyme reverse transcriptase, which converts viral RNA into DNA, allowing the virus to integrate into the host genome and replicate.
Step-by-step explanation:
In addition to RNA, retrovirus particles also contain the enzyme reverse transcriptase. This is the enzyme that carries out the process of reverse transcription, where the viral RNA is converted into DNA. This step is crucial for the viral life cycle, particularly for retroviruses such as HIV, which carries its genetic material in RNA form rather than DNA. The reverse-transcribed DNA is then integrated into the host's genome, allowing the virus to replicate using the host's cellular machinery. The drugs developed to treat retroviral infections, such as AZT, are designed to inhibit the activity of reverse transcriptase, thereby reducing viral replication without harming the host's cells.