Heat oven to 325. Shake flour in bag & place in 13*9*2" baking pan. Roll down top of bag. Add tomato sauce, water, bouillon, salt & pepper; squeeze bag gently to blend. Trim fat from roast; place in bag. Place in vegetables. Turn bag gently to coat ingredients with sauce. Close bag with twist tie; make 6 slits in top of bag. Bake 1 3/4 to 2 1/4 hours. To serve, spoon gravy from bag over roast & vegetables.