There are four historic views to the breaking of the bread and sharing of the cup.
The Roman Catholic position is that the transubstantiation or "substance across." It holds that in the Mass the bread and the wine become the body and blood of Jesus.
Lutherans believe in consubstantiation. This view holds that the body and blood of Jesus are present with the elements of the Lord's Supper.
Others hold to the view that grace is present with the elements, or that the partaker receives grace thereby which is not available otherwise.
Baptists believe that the Lord's Supper is symbolic. The bread and fruit of the vine are but symbols of the broken body and spilled blood of Jesus.