Was it unprofessional for my professor to yell at me?

I do think that is was unprofessional for your professor to yell at you and she should have taken you aside privately to speak with you about what's going on in your labs. I was a biology major once upon a time but ended up dropping most of my science classes at some point, I just knew that it really wasn't for me. With the first incident with handling the gel she may have responded out of disbelief or fear. Such as when a parent sees their chid doing something that they shouldn't be doing like getting ready to touch some hot. Instincts may automatically kick in and you may yell to prevent that child from reacting. But I still think that your professor was wrong and that maybe you need to speak privately with her. Sometimes when you feel targeted it makes it difficult to get on track and can be somewhat nerve wrecking.