I don't think anyone's saying not to do research, but at the same time, I honestly don't expect someone playing a character with expertise in a certain field to know said field incredibly deeply. Yes, some research should certainly be done, but unless your character's biology work is actually going to come up often, you don't need to be an expert. Is it better if you are? Yes, absolutely. But here's an example. My mother is a biologist. She's a microbiologist, to be specific. From talking to her, you generally would not know it. She's not sitting there talking about microbiology constantly. The most she generally mentions is maybe how a machine isn't working at the lab or how she got a new shipment of milk in. She also talks about things like how her boss is a computer geek, how one of the women she works with is very nice but smells horribly, and how she once punched a co-worker/friend and made him cry. Biology jobs are also... well, jobs, and the people who work them are actually people, and getting too very preoccupied with "[x] is a [insert career]!" can lead you to lose sight of the fact that [x] is also a person.
Additionally, biology (working with that, but this applies to a lot of things) is a huge field. You can be a microbiologist, a bio-engineer, a zoologist, etc. Figure out what your character does and focus on that in any research you do. Again, my mom's a microbiologist. She knows a lot about animals because she loves them, but she wasn't able to study zoology; thus, she doesn't know zoology on that level. Even with microbiology, at this point? I'd say she's mostly familiar with the knowledge she needs for her job. Not every biologist is out there doing cutting edge experiments, either. She tests water and milk for harmful bacteria.
The point I'm trying to make here is that you can stick to what you know and what you research without investing your entire life into studying biology. I'm going to be honest here, you're probably not going to attain the same level of knowledge as a real biologist without, you know, studying biology and working as a biologist. That people suggest you should be able to is a little unfair. In the end, your character probably isn't going to spend a lot of time gabbing about the intricacies of their career. Some people might do that, but a lot don't.
If the RP is going to have focus on your character's job, it becomes a lot more important, of course. Short of that, though? As background information, the "get a general background and then study what you need" approach is generally fine. In most cases, you really shouldn't be trying to "[insert] random bits of jargon into every third sentence". If you know you don't know how to talk about it... don't. When the subject of a job comes up, focus on how tired your character was from a hard day of work, how much his or her coworker annoys him/her, how that new secretary is awfully cute, etc. If the need to discuss biology comes up, on the other hand, do make sure you know what you're talking about before you start talking.
Setting and tone factors in, too. Washu from the Tenchi Muyo franchise is a scientific genius, but if you know anything about her or the series, you know it's all played for humor. Nobody's going, "BUT THAT DOESN'T FOLLOW THE REAL LIFE RULES OF SCIENCE!" in that case.