Preheat oven to 425 degrees.
In a small mixing bowl, combine yeast with warm water and let stand for 5 minutes. Then add buttermilk and stir.
In separate, medium size bowl, add flour, baking powder, salt, baking soda and sugar. Mix to combine.
Cut in shortening until the mixture is course.
Add buttermilk and yeast mixture, then stir with a fork until just combined. Be careful not to over mix.
Transfer dough onto a well-floured surface and knead 4-5 times.
Roll dough and cut with a a 2 inch pastry cutter. Place on lightly greased baking sheet. Cover and move to a warm area and let the biscuits rise for an hour.
Bake for 10 minutes or until biscuits are golden brown.