Grease and flour bottom of 9 or 10-inch tube pan.
Melt chocolate morsels in water over low heat, stirring until smooth and blended.
Cool.
Combine flour with soda, salt and baking powder.
Cream butter in large mixing bowl.
Gradually add 1 cup sugar; cream at high speed of mixer until light and fluffy.
Add egg yolks; beat well.
Combine bananas, sour cream and vanilla extract.
At low speed add alternately with dry ingredients to creamed mixture; begin and end with dry ingredients.
Blend well after each addition.
Stir in cherries.
Beat egg whites until soft mounds form.
Gradually add 1/2 cup sugar, beating until stiff.
Fold into batter.
Place 1/3 of batter in pan; drizzle 1/2 of chocolate mixture over batter.
Repeat with remaining batter and chocolate, ending with batter.
Bake at 350° for 50 to 60 minutes until cake springs back when touched lightly.
Do not invert.
Cool.
If desired, glaze top of cake, allowing to drip down sides or, cut in wedges and serve with whipped cream.