I agree with what was said but also, are you keeping track of what exactly you ARE missing? It could be that you're not as familiar as you think with certain topics; genetics, evolution, etc. Take some time and look at the type of questions you miss in bio and focus more on that.
For me, I've been missing questions on genetics, evolution and some organic reactions involving carboxylic acids. So today will be devoted to these topics; spending time reviewing the material and making sure I can answer questions thrown at me from any angle. The rest of the week will be back to tests.
It all comes down to what you're missing and where.