Which school is this for? And which course titles? Really, it depends. I've taken online courses where the lecture is online, but the labs are in person every so often. I've also taken ALL online courses, where you either do online lab exercises, or you purchase a lab kit through a designated company and you do labs in your home (including dissections - cool stuff!).
Microbiology was completely online for me. It was BIO 150...I think? Plenty of reading, but I earned an A or B...can't remember which. I also took BIO 141 online, with the at home lab kit. Lots of work, but again, as long as you keep up with it, you can do it. I earned an A in that, however, I had taken NAS 161/162 previously, so I already had a good background in it - but now schools don't really want to accept NAS courses!
In both courses, all quizzes and exams were online, so you can imagine how easy it was to pass those... lol.
So as with any online course, you definitely need to have discipline and be able to teach yourself, because if you're going for nursing, you will definitely use what you learn!