1. Preheat oven to 425F.
1. In a large mixing bowl, combine flour, baking powder, baking soda, salt and sugar.
2. Add buttermilk, mixing well.
3. Turn dough out onto a floured board and lightly knead until coarsely blended.
4. Roll out dough to about 1/2 inch thick; cut with 2 1/2 inch biscuit cutter.
5. Place biscuits on a lightly greased baking sheet and brush tops with melted butter.
6. Bake for 8 minutes or until golden brown. Serve with lots of butter and jam.