Yup - it will be tougher. If he is pre-med, junior year will actually be the most difficult of all. Orgo was one of my most difficult classes. I ended up reading every chapter, doing all of the suggested problems, and making hundreds of flash cards. Many of my Friday and Saturday nights were spent with my Orgo book. I really liked genetics, but the general consensus seemed to be that it to was a tough class. No sense in your son getting all stressed out this summer. It's doable, but it will be a challenge.