I didn't bother memorizing the structure, enveloped, RNA or DNA (yes which is kind of bad) but I knew it's pretty low yield to begin with and I just knew a few of them like HIV, herpes, adeno, just the really common ones from class or whatever. I had 0 about that, but I have a few questions on EBV, CMV, parainfluenza, and more or less the really common ones so don't sweat it i'd say. I asked my other friends and I don't really recall anyone saying they had really detailed weird viruses on the test.