This animation shows how a medication called AZT, which is a reverse transcriptase inhibitor, can be used to treat HIV/AIDS.

In order to complete its life cycle, HIV uses an enzyme called reverse transcriptase to convert its viral RNA to DNA. The animation illustrates how the drug azidothymidine, or AZT (also known as zidovudine or Retrovir), blocks the function of reverse transcriptase. AZT is a small molecule that is structurally similar to the nucleotide base thymidine. Reverse transcriptase can mistakenly incorporate AZT instead of thymidine into the viral DNA, which shuts down the reverse transcription process.

Depending on students’ background, it may be helpful to pause the animation at various points to discuss different molecules and their structures.