What determines the shape and function of a protein?

The function is determined by shape. The protein is determined by its primary structure which is the sequence of amino acids.
Amino acid sequence is determined by nucleotides in the gene (DNA)

Aphysical change is one that you can put in and remove like a ham sandwich. the stuff you put in there can be changem its not permanet. a chemical change is on that can't be change thats permanet. like when you make a cake and bake it. you can't get those ingredients back.