TEAS test science portion

I have to take the TEAS test as a final step for admittance on July 11th. I purchased the Kaplan nursing school entrance exam study guide. My concern is about the science. Is this study guide sufficient? Ive never taken any physics or chemistry classes. Ive been studying pretty hard for the past few days but I just dont feel that Im absorbing as much as I should. Does anyone have any pointers? Am I wasting my time with all of this DNA stuff or should I keep focusing on that?