Yeah there is a lot in the bio section but let me tell you that it can be done. I had only 1 bio class in college and it was 2 and a half years ago and I managed a 21 in bio. One of the things you have to keep in mind when you study bio is that you aren't just cramming facts into your head. You'll start to recognize the way the questions are asked and it will help tremendously. Often times you may not 'know' the answer but you'll learn how to quickly narrow down.
For example, one of the Kaplan practice questions asked which hormones were derived from cholesterol. When I was taking it, I had no clue but i recognized that cholesterol was a steroid and one of the answers ended with -oid and it was right.
Another time I saw a questions that asked about animal phyla characteristics and i noticed they listed 2 phyla plus for one of the phyla they listed 2 animals that fit within it plus another that was not a phyla at all [Like 1)chordata 2)annelida 3)shark 4)bird 5)hydra]. Obviously 1, 3, and 4 are all the same answer in terms of phyla so you can know those out and annelida has to be your answer since hydra not a phylum.
It involves a lot more 'thinking' and less 'knowing' that people expect. You'll gather knowledge every time you read, don't worry.