Bipolar plate and membrane electrode unit for a fuel cell arranged in a fuel cell stack, fuel cell and fuel cell stack

The invention relates to a bipolar plate (1) for a fuel cell (100), comprising a profiled anode plate (7) and a profiled cathode plate (8), each having an active region (6) and two distributor regions(2) for feeding and draining operating media to and from the active region (6), wherein the distributor regions (2) each have an anode gas main port (3) for supplying and discharging fuel, a cathodegas main port (4) for supplying and discharging oxidant, said cathode gas main port (4) being arranged such that, proceeding therefrom, cathode ducts (41) extend in a rectilinear manner at least overthe distributor region (2) of the bipolar plate (1) and have a direction of flow which corresponds to a main direction of flow in the cathode ducts (41) in the active region, and a coolant main port (5) for supplying and discharging coolant. According to the invention, provision is made for the coolant main port (5) and the anode gas main port (3) to be arranged adjacent to one another, adjacent to the cathode gas main port