This post is a response to an inquiry from Whitefox in a different forum asking for advice related to careers in sciences. Just to be open about where I am coming from: my BS is in Biochemistry from a small, private liberal arts college, my PhD is from a major (top 25, but not Harvard or Stanford) research university, and I am currently a research fellow running a project focused on the biochemistry of non-alcoholic fatty liver disease at the research foundation of a major hospital. I am also a new professor at a nearby university and teach courses in Human Physiology and Genetics. I like lists, so I'll just jump right in.
1. A BA or BS in biology will not get you very far if research is your goal. The market is saturated and the pay is poor.
2. An MS would help, but the MS degree in biology is fading and most people avoid it because financial aid is limited compared to the PhD. I would advise against it unless you have something very specific you are trying to do, and an MS is the best fit for it.
3. If you know you love research (please try it out in a lab for a summer first, at a minimum), a PhD from a reputable research university is a great career option. If the best you can get into is a mediocre state school, I would advise against it. You will always be at the bottom rung and it is hard to work out of that.
4. A major upside of a PhD at a good university is that there is no debt involved. Tuition is waved, and a stipend (25-30K is the norm) and health insurance are provided, giving you a fairly comfortable but simple life. If you don't get your own funding, you may have to teach part time to make this happen.
5. When you start, choose your advisor very carefully. This is huge. The project you work on will influence your future work enormously. The advisor you choose is probably more important than the university you choose. Also, try to get some time with your potential advisor's current students and postdocs outside of their lab and get their honest opinions about the lab. Some labs/advisors are nightmares and people stumble into a bad situation without knowing it. Also, make sure the lab has a history of steady funding. You can search this through the NIH REPORTER system.
6. Once you pick a project, you better put everything you have into it. If you are not ready to put in a lot of focussed work and be a relentless (but socially acceptable) self-promoter, you will stall. You need to ask important questions, produce good data, write as much as you can, and travel to meetings to let other people know about your ideas.
7. All of this hard work is necessary because the job market for life sciences PhDs is terrible in some ways. It is easy to get a job, but it is extremely difficult to get an academic job running your own lab, or even working as a project scientist. You have to be at the tope of your game and commit at about 8-10 years from the start of your PhD to make it happen (5-6 for PhD, 3-5 for postdoc). This entire time is going to be very stressful and give you low pay, so you better love what you are doing. Many people fade by the end and change their career plan, wishing they had done something else.
I got through all of this relatively quickly (4 years PhD and 1.5 years postdoc) and don't regret my decision, but many are not so lucky. It can be a long and grueling path. Only do it if you are passionate about the research and can maintain a high level of self-motivation without someone looking over your shoulder. I hope this helps.