I am not currently enrolled in PT school as of yet so I apologize if my assumption may seem out of context. (correct me if im wrong)
I would assume that all 3 would be useful to some extent in PT school.
Physics: covers the bio mechanical aspect of PT and helps you to rehabilitate your client (especially if an athlete) back to their everyday activities. Certain activities (such as tennis) require understanding of acceleration to the ball, the force required to hit the ball "swing rate", and so forth. The basis of these calculations and understanding how to increase them come from the basis of physics.
General Biology (The Study of Life): In this class, you cover quite a lot (hence "general") such as plant biology, cell biology, some anatomy, the earth, and other minute aspects of scientific life. I never took much from this except the anatomy section and the cell biology. This is just a pre-req for the other classes you will take [i.e., Anatomy, Kinesiology, Nutrition, etc.]
Chemistry: This class DOES concern us at PT but it is more directed to Nutrition. Chemistry primarily teaches you the compounds (of atoms), their structures, behaviors, and how they react in isolation as well as combination with other materials/chemicals. So as you can tell, not a class you should entirely focus on but there are some good key points along the class (such as the structure of a fatty acid chain) to know.
Morale of the post: All of these classes have "aspects" and certain points that you should take away from each class but all 3 of them are such basic, general courses that you should not lose sleep over memorizing all the information in them. You will run into much deeper and specialized classes following these; these 3 classes just give you some baseline knowledge for each area will help create a foundation that you can carry with you as you go more in-depth with your higher-thousand classes.
Hope that helps and like i said, I am not currently in PT school so take this post with a grain of salt but I hope this has helped you in some way.