That's odd I was always told that you should NEVER use a comma before an and in a list ,and (see that'snot incorrect there, I'm going on to a different idea, not just listing) I would be astonished if a British teacher/proffesor told me to use it before the final item on a list. It is almost always incorrect to say ",and" because a comma is essentially a short-form way of writing "and" in most cases
P.S. please could the non-native (and native!) english speakers note: grammAr sentenCe, not grammer and sentense