If you only plan to study the night before the exam, drop the course now. Biology requires repetitive study habits. You need to go over material, clear up any confusion in your notes, go over the material again, and then go back and review older material. Material in the Natural Sciences is cumulative. When you take a quiz or exam, don't assume that you'll never see that material again.
Concepts build on one another.
You need a knowledge of chemistry to understand cell biology. You need a knowledge of both chemistry AND cell biology to understand genetics. You need an understanding of chemistry, cell biology AND genetics to understand evolutionary theory. And you need all of the preceding information to understand ecology and physiology. Get help as soon as you need it.