Abstract: A bioreactor for use on a moving platform comprises a bag. According to a first aspect, the bag defines a three-dimensional geometrical shape including at least one lower collecting vertex in which at least two edges of the geometrical shape meet at an angle which is preferably not greater than 90°. The bioreactor further includes at least one port or sensor, preferably a biomass sensor, arranged in the vicinity of the collecting vertex. According to a second aspect, the bag defines a two-dimensional geometrical shape or a three-dimensional geometrical shape. The geometrical shape includes at least one edge, in which at least two faces of the geometrical shape meet at an angle which is preferably not greater than 90°. A longitudinal port/sensor element is arranged along the edge and includes several ports and/or sensors. A bioreactor motion system comprises a moving platform and a bioreactor according to the first or second aspect.