Can I get a Master's that is different than my Undergrad degree?

So I’m about to graduate with an B.A. in Sociology, but I was wondering if I would be able to get a masters (and later phD) in Biology? I’ve taken a few bio classes and loved them and I really want to persue this career path instead.

Is it possible to get a Master’s in a major different than my Bachelor’s? or Would I have to completely re-do my bachelors?

Of course it’s possible. But you have to qualify for the program, not just have taken a few classes. Look at the requirements. Generally, grad school is advanced study, with some research focus. Doesn’t sound like you’re ready for that.

You may need to take some extra classes to meet whatever requirements a graduate program might expect. I have known liberal arts majors who spent a couple of years taking courses to apply to med school. It might be easier for someone with your background to go into an MA program that does not already include a PhD track. You could later apply to a PhD program if you want to follow that track.