I did bio, chem, physics and maths at AS as well as General Studies as the school made us, I dropped Gen Stud and Physics and Im the proud holder of an offer for Glasgow! In my opinion definitely do chemistry and maths, and i would recommend biology, but physics isnt required so do something your good at and enjoy so you will get a good grade!
I have a friend who is doing Bio, Chem and French and got offers too!
Hope this helps a little!